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  1. #1
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    Default Thermal expansion tank and pressure

    At an inspection two weeks ago the water pressure was consistently 65 psi from two different bibs over 15-20 minutes, an hour or so apart. A 2003 gas WH was properly installed, as was a newer (2 years) pressure relief valve at the main supply. The buyers moved in yesterday and found the pilot had gone out, so no hot water. They called for advice and I went over as a courtesy. In the meantime the new homeowner also called a plumber under the home warranty who arrived while I was there.

    The plumber installed a new thermocouple and voila - hot water. Then, on his own volition, checked cold supply pressure. His meter read 90 psi and rising to about 110. He did that test while he had the WH temp. Control turned to max. and recommended a thermal expansion tank be installed to the tune of $385 because of the rising psi while the water heated. He used his gauge to show the water pressure rising, alarming the owner, which leveled off at 110 psi. I am familiar with the property and previous owners. To my knowledge there has never been any issue with the installed TPR valve opening or any other abnormality in the plumbing system. So, was this an attempt at an 'up-sell' on the plumbers part (he was only making $60 on the warranty call out) . Or is there a real need for the expansion tank based on the aforementioned. They are not required in this jurisdiction. Clearly the WH is aging out. The plumber said he could install a new 50 gal and the expansion tank at today's price of $1750.

    Afterwards, the new homeowner went to HD and purchased their own pressure gauge, which gave a reading of slightly more than 60 psi two hours after the plumber left.

    Any thoughts would be most welcome.

    Inspection Referral SOC

  2. #2
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    At an inspection two weeks ago the water pressure was consistently 65 psi from two different bibs over 15-20 minutes, an hour or so apart. A 2003 gas WH was properly installed,
    Wh was not properly installed. This is a closed system. A closed system is required to have a expansion tan or pressure relief at the WH.
    Quote Originally Posted by Ian Page View Post
    as was a newer (2 years) pressure relief valve at the main supply.
    The Pressure relief valve was not working and should be located at WH.

    Quote Originally Posted by Ian Page View Post
    The buyers moved in yesterday and found the pilot had gone out, so no hot water. They called for advice and I went over as a courtesy. In the meantime the new homeowner also called a plumber under the home warranty who arrived while I was there.
    Quote Originally Posted by Ian Page View Post
    The plumber installed a new thermocouple and voila - hot water. Then, on his own volition, checked cold supply pressure. His meter read 90 psi and rising to about 110. He did that test while he had the WH temp. Control turned to max. and recommended a thermal expansion tank be installed to the tune of $385 because of the rising psi while the water heated. He used his gauge to show the water pressure rising, alarming the owner, which leveled off at 110 psi.
    The plumber was doing exactly as he should.
    Quote Originally Posted by Ian Page View Post
    I am familiar with the property and previous owners. To my knowledge there has never been any issue with the installed TPR valve opening or any other abnormality in the plumbing system. So, was this an attempt at an 'up-sell' on the plumbers part (he was only making $60 on the warranty call out) . Or is there a real need for the expansion tank based on the aforementioned. They are not required in this jurisdiction.
    Not an improper up sell, an expansion tank was needed, the plumber was correct.

    Quote Originally Posted by Ian Page View Post
    Clearly the WH is aging out. The plumber said he could install a new 50 gal and the expansion tank at today's price of $1750.
    Quote Originally Posted by Ian Page View Post
    Afterwards, the new homeowner went to HD and purchased their own pressure gauge, which gave a reading of slightly more than 60 psi two hours after the plumber left.
    .
    After the expansion tank was installed, there will be no (very little) pressure rise due to thermal expansion.

    Sorry, you should have reported no expansion tank was installed

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  3. #3
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    At an inspection two weeks ago the water pressure was consistently 65 psi from two different bibs over 15-20 minutes, an hour or so apart. A 2003 gas WH was properly installed, as was a newer (2 years) pressure relief valve at the main supply. The buyers moved in yesterday and found the pilot had gone out, so no hot water. They called for advice and I went over as a courtesy. In the meantime the new homeowner also called a plumber under the home warranty who arrived while I was there.

    The plumber installed a new thermocouple and voila - hot water. Then, on his own volition, checked cold supply pressure. His meter read 90 psi and rising to about 110. He did that test while he had the WH temp. Control turned to max. and recommended a thermal expansion tank be installed to the tune of $385 because of the rising psi while the water heated. He used his gauge to show the water pressure rising, alarming the owner, which leveled off at 110 psi. I am familiar with the property and previous owners. To my knowledge there has never been any issue with the installed TPR valve opening or any other abnormality in the plumbing system. So, was this an attempt at an 'up-sell' on the plumbers part (he was only making $60 on the warranty call out) . Or is there a real need for the expansion tank based on the aforementioned. They are not required in this jurisdiction. Clearly the WH is aging out. The plumber said he could install a new 50 gal and the expansion tank at today's price of $1750.

    Afterwards, the new homeowner went to HD and purchased their own pressure gauge, which gave a reading of slightly more than 60 psi two hours after the plumber left.

    Any thoughts would be most welcome.
    When you say "Pressure Relief Valve", are you by chance referring to a PRV(pressure reducing valve)? If it is a PRV, it is a closed system as Rick noted and you should have noted that it did not have an expansion tank or valve. It does not matter if the AHJ does not require them, the water heater manufacturer requires it.

    Last edited by Scott Patterson; 05-21-2014 at 06:07 AM.
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  4. #4
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    Default Re: Thermal expansion tank and pressure

    Yeah, crank that sucker up to Max and the thermal expansion of the water will go up (I've not measured the pressure at Max as I've never turned a water heater to Max).

    The plumber was doing a dog and pony show to sell the thermal expansion tank at an outrageous price - didn't work except for convincing the owner to install a thermal expansion tank themselves.

    Every water heater should have a means to relieve thermal expansion (thermal expansion tank is best option) on it, every water heater on a closed system (with a pressure reducing valve) shall have a means to relieve thermal expansion.

    It's the difference between "should" and "shall" - but the need for one is there.

    Jerry Peck, Construction / Litigation Consultant
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  5. #5
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jerry Peck View Post
    Yeah, crank that sucker up to Max and the thermal expansion of the water will go up (I've not measured the pressure at Max as I've never turned a water heater to Max).

    The plumber was doing a dog and pony show to sell the thermal expansion tank at an outrageous price - didn't work except for convincing the owner to install a thermal expansion tank themselves.

    Every water heater should have a means to relieve thermal expansion (thermal expansion tank is best option) on it, every water heater on a closed system (with a pressure reducing valve) shall have a means to relieve thermal expansion.

    It's the difference between "should" and "shall" - but the need for one is there.
    You say dog and pony show, the plumber (and myself) say it is a valid method that demonstrates just what is happening. Then the plumber explained what was needed to correct it. As for the price being an outrageous price, some people think the same about home inspectors. Furthermore, the price had nothing to do if an expansion tank was needed or not.

    Another point
    ALL WHs should be a closed system (shutoff valve on the cold water line at the WH).
    Since all WHs should be a closed system then naturally, it stands to reason that all WHs should have expansion tanks (or equivalent), regardless if the whole system is open or closed.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  6. #6
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Rick - I would suggest that you do some research on the amount of pressure increase due to thermal expansion in a water heater. The amount of pressure increase does not warrant an expansion tank.
    Maybe I wasn't as clear as I would of liked to be.
    I did not say (nor do I think) the need for an expansion tank is determined by how much the pressure increase is.
    The need for an ET is because there is thermal expansion.
    When the plumber measured the pressure rising, he demonstrated what the effect of thermal expansion does without an ET installed.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  7. #7
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    Default Re: Thermal expansion tank and pressure

    Jim
    It was arrogant of me when I told you of my background in burglar and fire alarms. Even though it was fact. But it was also fair of me to inform you that I am educated in that area.
    Similarly, (and without any arrogance intended) I am educated in this area as well.


    Quote Originally Posted by Jim Abram View Post
    Rick - The reason that an expansion tank would be installed is to relieve pressure.
    Actually to prevent pressure from building, but yes, I agree


    Quote Originally Posted by Jim Abram View Post
    Without going into basic science , if a fluid or gas expands in a closed container it creates additional pressure. The expansion tank creates an outlet for the expansion and eliminates pressure increases.
    Yes


    Quote Originally Posted by Jim Abram View Post
    If you block both the inlet and outlet of a hot water tank and turn it up to max you may see 110 psi but this is not normal operating conditions.In normal operating conditions the expansion and pressure increase is minimal and is generally not an issue.
    Jim, unless I misunderstand what you are saying, that is incorrect.
    Water heated in a closed system will always result in a pressure increase, every time, no exceptions, ever.
    The higher the temperature increase, the higher the pressure increase.

    Quote Originally Posted by Jim Abram View Post
    Seeing an expansion tank on a water heater ,I have found to be a very rare circumstance ;probably in the vicinity of 1 per 5000 tanks observed.
    Not to be offensives, by your words you seem to have only a limited experience with expansion tanks in your area. Not so with me, I see them often. And the houses that don't have one, eventually (soon) have busted washer supply hoses/ fill valves, busted dishwasher hoses /fill valve, busted refrigerator hose / fill valve, and sometimes a leaking WH.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  8. #8
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    You say dog and pony show, ...
    I called it a dog and pony show because it shouldn't be needed and is for show and tell.

    the plumber (and myself) say it is a valid method that demonstrates just what is happening.
    It's a method, not sure that I would call it a valid method.

    Another point
    ALL WHs should be a closed system (shutoff valve on the cold water line at the WH).
    Since all WHs should be a closed system then naturally, it stands to reason that all WHs should have expansion tanks (or equivalent), regardless if the whole system is open or closed.
    A WH should not be a closed system - anyone who closes the cold water supply valve with the water heater 'on' deserves the lesson they are about to learn.

    Jerry Peck, Construction / Litigation Consultant
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  9. #9
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    @ Rick -"The higher the temperature increase, the higher the pressure increase. "

    Yes .

    What
    is the pressure increase in a closed tank when the temperature is raised from 50 degrees/ F to 130 degrees /F


    I cannot say. It will largely depend on the size of the tank (volume of water heated), and the water lines ( length and material, (PEX will allow for more expansion than say galv or copper))

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  10. #10
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jerry Peck View Post
    I called it a dog and pony show because it shouldn't be needed and is for show and tell.
    On this forum you use words and sometimes diagrams to help illustrate your opinions.
    But you think it's a dog and pony show to use a pressure gauge to show a pressure increase.
    And yes, it is needed, so that the HO understands what the plumber is describing and sees it himself.


    Quote Originally Posted by Jerry Peck View Post
    It's a method, not sure that I would call it a valid method.
    How better would you show a HO the water pressure than with a water pressure gauge?



    Quote Originally Posted by Jerry Peck View Post
    A WH should not be a closed system - anyone who closes the cold water supply valve with the water heater 'on' deserves the lesson they are about to learn.
    Yes, a water SHOULD not be on a closed system, sometimes (often, many times) they are.
    They NEED to be taught a lesson, really?

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  11. #11
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Rick - It has nothing to do with any of those factors. This is a closed tank.
    OK, all faucets are off, the cold water valve is off at the water heater and there is not an expansion tank (or similar)
    I still do not know what the pressure rise would be.
    But, when the pressure reaches 150 PSI, hopefully the TPR valve will open.
    I'm not sure if that is what you are looking for.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  12. #12
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    Default Re: Thermal expansion tank and pressure

    Have to agree on the Dog and Pony Show. The plumbers demonstration (science experiment) was a selling tool for the system upgrade. In sales you use different techniques to close the sale. So you demonstrating a reason for urgency. Was the system in danger of an immediate disaster, don't think so. The TPR valve would have released the pressure. The rub is that many jurisdictions now require the installation of the expansion tank even if there is no need of one. Just a blanket requirement with a new HWH installation. So you will end up with one sooner or later if required, someone will force the installation.

    The question of the price quoted may be only relative to the local going rate for work.

    More than one factor goes into the need for the expansion tank for it to be the safety necessity. Does it hurt to have Exp Tank, no. Is it hard to install, no. Is it expensive, shouldn't be. They run $40 to $50. Other materials are less than $10. Also, plumber's never overcharge.


  13. #13
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    But you think it's a dog and pony show to use a pressure gauge to show a pressure increase.
    Rick,

    It wasn't using the gauge to show a pressure increase that I was referring to as the dog and pony show ... I thought I was clear (but obviously was not) that it was cranking the WH thermostat to Max that I was referring to.

    Cranking the thermostat to Max is like "putting the pedal to the medal" when showing or explaining "how fast does it go".


    How better would you show a HO the water pressure than with a water pressure gauge?
    I've always given them the benefit of doubt and just explained it to them ... not surprisingly (to me), they always seem to get it.

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jerry Peck View Post
    Rick,

    It wasn't using the gauge to show a pressure increase that I was referring to as the dog and pony show ... I thought I was clear (but obviously was not) that it was cranking the WH thermostat to Max that I was referring to.

    Cranking the thermostat to Max is like "putting the pedal to the medal" when showing or explaining "how fast does it go".
    OK lets go with the thermostat set to max (HOT)
    Does the manufacturer not allow the thermostat to be set at max?
    If so, I'm curious as to why it can be set to max.
    How about checking a light dimmer switch, should that also be set on low so that it does not overheat.


    Quote Originally Posted by Jerry Peck View Post
    I've always given them the benefit of doubt and just explained it to them ... not surprisingly (to me), they always seem to get it.
    Perhaps the plumber thought the HO would not believe him without some evidence the HO could see. I hardly, if ever (actually never) believe what the plumber (ceptin Ron) tells me.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  15. #15
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    OK let's go with the thermostat set to max (HOT)
    Does the manufacturer not allow the thermostat to be set at max?
    If so, I'm curious as to why it can be set to max.
    How about checking a light dimmer switch, should that also be set on low so that it does not overheat.
    So I can put the pedal to the metal in my car let 'er rip ... 'cause there is a pedal and there is metal and the manufacturer made it that way?

    Perhaps the plumber thought the HO would not believe him without some evidence the HO could see. I hardly, if ever (actually never) believe what the plumber (ceptin Ron) tells me.
    Okay ... got me there because I'm sorta like that too. And I'm not even from Missouri.

    Jerry Peck, Construction / Litigation Consultant
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  16. #16
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    Default Re: Thermal expansion tank and pressure

    Thank you guys, please keep up the dialogue.
    Jerry...at last, I agree with your assessment 100% and actually used the same 'dog and pony show' to the homeowner, though they were not familiar with the term. After the thermocouple install the plumber went to his truck for a few moments and I told the homeowner to expect him to find some 'deficiency'. Though the plumber was efficient and did his job, I just knew that a minimal service fee, including parts, wasn't going to cut it.
    So how / why would his pressure gauge show over 90 psi, when both the earlier and after reads were 60-65? Defective gauge specifically for duping customers ???

    Interestingly, he made absolutely no mention or suggestion of adjusting the pressure regulator down to compensate for his high read. I was half expecting him to say the pressure regulator / reducing valve was shot but it was relatively new and looks in good shape. His only explanation for the changing pressure was because, in his opinion, long runs from the WH to the kitchen!!! In fact in this install the kitchen is probably within 30' of supply line.

    Rick
    Seems to me that if the need for expansion tanks is as great as you experience the manufacturers would be incorporating it into the design, rather than an add-on by a different company. I rarely see ETs, maybe one in 500. 80% of my inspections are on newer properties, mostly since the late 1980s. They are typically not even installed in brand new homes, when installation, if deemed necessary, would be easiest.


  17. #17
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jerry Peck View Post
    So I can put the pedal to the metal in my car let 'er rip ... 'cause there is a pedal and there is metal and the manufacturer made it that way?
    You have a Jag, jump on the interstate and let er rip.
    The car can take it.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  18. #18
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    Default Re: Thermal expansion tank and pressure

    To my knowledge not all manufactures require an expansion tank in my area, either electric or gas, and I don't think the building code up here requires it because I don't see them installed in new homes. Once again blanket statements don't always jive with what is or not required by geographic location.


  19. #19
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Raymond Wand View Post
    To my knowledge not all manufactures require an expansion tank in my area, either electric or gas, and I don't think the building code up here requires it because I don't see them installed in new homes. Once again blanket statements don't always jive with what is or not required by geographic location.
    I do not know what your codes are. As for manufacturers not requiring an expansion tank (or equal) on a closed system, that, you will need to show me.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  20. #20
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Jerry - Do you have any documentation that there is a need for these components.
    Quote Originally Posted by Jerry Peck View Post
    Every water heater should have a means to relieve thermal expansion (thermal expansion tank is best option) on it, every water heater on a closed system (with a pressure reducing valve) shall have a means to relieve thermal expansion.

    It's the difference between "should" and "shall" - but the need for one is there.
    The wording started out as this (2000 IRC):
    - P2903.4 Thermal expansion. - - In addition to the required pressure relief valve, an approved device for thermal expansion control shall be installed on any water supply system utilizing storage water heating equipment whenever the building supply pressure is greater than the required relief valve pressure setting or when any device, such as a pressure reducing valve, backflow preventer or check valve, is installed that prevents pressure relief through the building supply. The thermal expansion control device shall be sized in accordance with the manufacturer’s installation instructions.

    And, over the various code editions is now at this (2012 IRC):
    - P2903.4 Thermal expansion control.
    - - A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
    - - P2903.4.1 Pressure-reducing valve.
    - - - For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
    - - P2903.4.2 Backflow prevention device or check valve.
    Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.

    Jerry Peck, Construction / Litigation Consultant
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  21. #21
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    Default Re: Thermal expansion tank and pressure

    Here is one

    4. If the combination temperature and pressure relief valve on the appliance discharges periodically, this may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct this situation. Do not plug the combination temperature and pressure relief valve outlet for any reason.
    http://www.bradfordwhite.com/sites/d...-44422-00L.pdf

    Well it doesn't specifically state one is required unless the TPR is discharging periodically on a closed system.

    I am up at the cottage and I am sure my electric hot water tank (at home) instruction manual does not state a expansion tank is required, will have to check the manual when I get home.

    Just don't see many in the field even with water meter, but don't see many homes with pressure reducing valves or one way valves with them installed, but do see expansion tanks on hot water heating systems.


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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    So how / why would his pressure gauge show over 90 psi, when both the earlier and after reads were 60-65? Defective gauge specifically for duping customers ???
    The 60 PSI is the supply pressure
    The 90+ PSI is supply pressure + the effect of thermal expansion


    Quote Originally Posted by Ian Page View Post
    Interestingly, he made absolutely no mention or suggestion of adjusting the pressure regulator down to compensate for his high read.
    No need to adjust the pressure regulator.
    The supply pressure was good (= or < 80 PSI)
    Also adjusting the pressure would have no effect or thermal expansion.

    Quote Originally Posted by Ian Page View Post
    I was half expecting him to say the pressure regulator / reducing valve was shot but it was relatively new and looks in good shape.
    At 60 PSI there is no reason to expect the pressure regulator to be defective.

    Quote Originally Posted by Ian Page View Post
    Rick
    Seems to me that if the need for expansion tanks is as great as you experience the manufacturers would be incorporating it into the design, rather than an add-on by a different company. I rarely see ETs, maybe one in 500. 80% of my inspections are on newer properties, mostly since the late 1980s. They are typically not even installed in brand new homes, when installation, if deemed necessary, would be easiest.
    Expansion tanks (or equal) are only required on a closed system.
    To be a closed system there will be installed a pressure regulator and/or a backflow preventer.
    Water suppliers are working to install backflow preventers but it is very costly, and residential customers are low on the list.
    BTW
    Instead of an expansion tank, there may be a pressure relief valve.
    My water supplier will even give you one that attaches to the washer hose and drain.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  23. #23
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    Default Re: Thermal expansion tank and pressure

    For those who are not believers in thermal expansion, have you seen the Watts video "Explosion! Danger Lurks!"?

    http://constructionlitigationconsult...nger_Lurks.wmv

    Last edited by Jerry Peck; 05-21-2014 at 05:58 PM. Reason: correcting title
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Raymond Wand View Post
    Here is one



    http://www.bradfordwhite.com/sites/d...-44422-00L.pdf

    Well it doesn't specifically state one is required unless the TPR is discharging periodically on a closed system.

    I am up at the cottage and I am sure my electric hot water tank (at home) instruction manual does not state a expansion tank is required, will have to check the manual when I get home.

    Just don't see many in the field even with water meter, but don't see many homes with pressure reducing valves or one way valves with them installed, but do see expansion tanks on hot water heating systems.
    Pretty much looks like this manufacturer wants you to install an expansion tank if it is a closed system.
    Bold added

    If this water heater is installed in a
    closed water supply system, such as the
    one having a back-flow preventer in the
    cold water supply, provisions shall
    be made to control thermal expansion. DO NOT operate this water heater in
    a closed system without provisions for controlling thermal expansion.

    - - - Updated - - -

    Quote Originally Posted by Jerry Peck View Post
    For those who are not believers in thermal expansion, have you seen the Watts video "Explosion! Danger Lurks!"?

    http://constructionlitigationconsult...nger_Lurks.wmv
    Good link Jerry

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  25. #25
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Seems like there is a limited amount of conditions that require a thermal expansion control.This is not the "every water should have"by any means that you claimed.

    What is Jerry going to post next ? Reefer madness?
    Jim,

    As is typical of you, you insist on continuing to make sure that we know that you either: a) do not know how to read/understand what you read; b) don't really care what is said and post whatever you want to post.

    I doubt you could continually do b) without err for so long, thus it must be a).

    Quote Originally Posted by Jerry Peck View Post
    Every water heater should have a means to relieve thermal expansion (thermal expansion tank is best option) on it, every water heater on a closed system (with a pressure reducing valve) shall have a means to relieve thermal expansion.

    It's the difference between "should" and "shall" - but the need for one is there.
    Jim, what part of the above do you NOT understand? I am offering to help you in your reading comprehension.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    You have a Jag, jump on the interstate and let er rip.
    The car can take it.
    But can the interstate and traffic take it? Just like it is not 'just' the water heater to be concerned about when cranked up to Max - it is the piping system, the fixtures, and the occupants.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Take a look at the link below. Pressure can build up dramatically. I have parts of a water heater in my garage that built up enough pressure to make the concave bottom convex. I removed that from a house I inspected (after the owner had a new one installed). Since that time I have seen two others do the same thing. I believe water heaters are tested to 300 psi, so the pressure would have had to exceed that. Yes, the TPV should have relieved, but some clog up with minerals.

    Once you know what it looks like you can spot this with a gas water heater from half way across the room. The vent tube at the center of the tank will be below the top of the housing and the inlet and outlet pipes will be tilted inward.

    http://www.inspectigator.com/files/E...eem_-_1209.pdf


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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jerry Peck View Post
    it is not 'just' the water heater to be concerned about when cranked up to Max - it is the piping system, the fixtures, and the occupants.
    Are you suggesting the water pipes and fixtures can not withstand the "HOT" water?
    As for occupants, I don't understand what you are getting at.
    A properly working water heater does not heat the water to a temperature that would damage water pipes or fixtures. But of course, you know this, don't you?

    Getting back to the original concern.
    The plumber set the temperature to max "HOT".
    No mater how you want to spin it, there is nothing wrong with that.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    Are you suggesting the water pipes and fixtures can not withstand the "HOT" water?
    I am suggesting paying close attention to the link you 'Liked'.

    Quote Originally Posted by Mark Reinmiller View Post
    - - - Updated - - -

    Quote Originally Posted by Jim Abram View Post
    Jerry - 'Every water heater should have a means to relieve thermal expansion,( thermal expansion tank is the best option), on it . Is not a correct statement. That I understand and that is what you do not seem to comprehend.
    Jim,

    Go back and read ALL of that post, then post ALL of it in your quote.

    Then read the information in this link Mark posted:
    Quote Originally Posted by Mark Reinmiller View Post


    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Here is a simple and accurate explanation of thermal expansion..

    http://www.google.com/url?sa=t&rct=j...,d.b2U&cad=rja

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

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    Default Re: Thermal expansion tank and pressure


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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    At an inspection two weeks ago the water pressure was consistently 65 psi from two different bibs over 15-20 minutes, an hour or so apart. A 2003 gas WH was properly installed, as was a newer (2 years) pressure relief valve at the main supply. The buyers moved in yesterday and found the pilot had gone out, so no hot water. They called for advice and I went over as a courtesy. In the meantime the new homeowner also called a plumber under the home warranty who arrived while I was there.

    The plumber installed a new thermocouple and voila - hot water. Then, on his own volition, checked cold supply pressure. His meter read 90 psi and rising to about 110. He did that test while he had the WH temp. Control turned to max. and recommended a thermal expansion tank be installed to the tune of $385 because of the rising psi while the water heated. He used his gauge to show the water pressure rising, alarming the owner, which leveled off at 110 psi. I am familiar with the property and previous owners. To my knowledge there has never been any issue with the installed TPR valve opening or any other abnormality in the plumbing system. So, was this an attempt at an 'up-sell' on the plumbers part (he was only making $60 on the warranty call out) . Or is there a real need for the expansion tank based on the aforementioned. They are not required in this jurisdiction. Clearly the WH is aging out. The plumber said he could install a new 50 gal and the expansion tank at today's price of $1750.

    Afterwards, the new homeowner went to HD and purchased their own pressure gauge, which gave a reading of slightly more than 60 psi two hours after the plumber left.

    Any thoughts would be most welcome.
    The plumber was right on track and protecting the clients, even though everyone else missed it. (sorry Ian) If the pressure is over 80 psi, it is wrong and needs repair. In this case, the correct repair is to install a pressure relief device. Not everyone, including some inspectors understand the thermal expansion phenomenon so the "dog and pony show" is a good device to demonstrate the high pressure in an otherwise correctly functioning system. I would rather call it a "show and tell" and something I would do. We are supposed to be the experts and shame on use for not learning and going beyond the basics in HI 101, although this is pretty basic in my opinion.
    Just because the TPR valve does not trip does not mean the system pressures are acceptable, only that it is below the settings of the valve. There is a great deal of room between the maximum allowed 80 psi and the 150 psi when the TPR trips.
    This over pressure IS harmful to systems.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Luttrall View Post
    The plumber was right on track and protecting the clients, even though everyone else missed it. (sorry Ian) If the pressure is over 80 psi, it is wrong and needs repair. In this case, the correct repair is to install a pressure relief device. Not everyone, including some inspectors understand the thermal expansion phenomenon so the "dog and pony show" is a good device to demonstrate the high pressure in an otherwise correctly functioning system. I would rather call it a "show and tell" and something I would do. We are supposed to be the experts and shame on use for not learning and going beyond the basics in HI 101, although this is pretty basic in my opinion.
    Just because the TPR valve does not trip does not mean the system pressures are acceptable, only that it is below the settings of the valve. There is a great deal of room between the maximum allowed 80 psi and the 150 psi when the TPR trips.
    This over pressure IS harmful to systems.
    Jim, you have my original post there so you must have read it.

    The original pressure taken was 65psi. Nothing changed, the house was unoccupied, the WH was set to medium heat. At some point the thermocouple goes awry, WH fails to heat water and at two weeks after the first read a plumber is called for repairs. He takes his reading with his gauge from the same bib and gets a reading rising from 90 psi. leveling to 110 psi. The only difference now is that the WH is cranked to Max. Hot. Two hours later, now with the WH set to medium again the pressure at the same bib reads just under 65 psi and steady.

    What am I missing here, where is the dangerous condition that warrants thermal pressure adjustment? At no time did the TPR valve disharge though being 10 years old, I assume original to the WH, it could be faulty.

    Expansion tank installation in this area is a rarity, to say the least. Never seen one installed in new construction in the same water district and same zip code, so what makes this particular home unique? It's a regular tract home in the middle of an established residential estate.

    Should we, as Inspectors, recommend thermal tank installation as a matter of course, irrespective of pressure gauge reading?

    Last edited by Ian Page; 05-22-2014 at 12:37 AM.

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    Default Re: Thermal expansion tank and pressure

    Ian
    This is a list of inspectors that said there needed to be an expansion tank installed on that WH
    Myself, post #1; Scott #2; Jerry #3; and Jim #41

    There was some discussion about other points. but not one person said an expansion tank was not needed on that water heater

    You didn't know, sometimes that happens.
    Accept it, learn from it, and be a better inspector because of it.

    People that are unwilling to learn from their mistakes are sure to repeat the mistake again.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Should we, as Inspectors, recommend thermal tank installation as a matter of course, irrespective of pressure gauge reading?
    Do you recommend the installation of GFCI protection or GFCI receptacles at wet locations which do not have GFCI protected receptacle outlets?

    If so, why?

    If not ... why not?

    The expansion tank is in that same category, so if you recommend installing GFCIs then the answer to your question is: Yes, inspectors recommend installing thermal expansion tanks as a matter of course.

    If an inspector does not recommend installing GFCI protection at wet areas when GFCI protection is not present ... well, why change anything now, no reason to start recommending modern safety practices to protect the client.

    You did ask.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Sorry Jerry - Your logic is faulty. GFCI protection is a widely accepted safety upgrade and is now required by Code. Thermal expansion tanks are neither.
    There is no need for an expansion tank in the majority of water heater installations.
    Using your logic, we should install safety nets above all houses to prevent airplane impact damage.
    Sorry Jim - your grasp of requirements is completely lacking.

    You said "GFCI protection is a widely accepted safety upgrade and is now required by Code."

    GFCI protection is a widely accepted safety upgrade - that part you got right, and it became a widely accepted safety upgrade because people recognized its benefits and recommended the upgrade.

    GFCI protection safety upgrade is not now required by code - you completely missed that one, another of your Jim's Code things you have in your mind which you think should be done?

    Thermal expansion tanks are also widely recognized as an accepted safety upgrade - just because *you* do not recognize it for what it is, and a few others do not recognize it either, does not mean that is it not widely recognized - it is.

    Thermal expansion tanks are also required by code - you completely missed that one too, another of your Jim's Code things you have in your mind which you think is not required?

    GFCI upgrades is NOT required by code.

    Like GFCI protection requirements - which is required at specific locations/conditions - thermal expansion tanks requirements apply at specific conditions ... not sure how you can miss them being similar ... oh, wait, I am sure how *you* can miss them because if they do not fall within Jim's Code they are not needed even if code required, and if they are in Jim's Code they are needed even if not code required - by Jim's Code that makes them quite similar ... Jim's Code.

    Looking forward to the end of next week, aren't you?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Mark Reinmiller View Post
    Mark,

    Great photos.

    Shows what can happen.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Sorry Jerry - Your logic is faulty. GFCI protection is a widely accepted safety upgrade and is now required by Code. Thermal expansion tanks are neither.
    There is no need for an expansion tank in the majority of water heater installations.
    Using your logic, we should install safety nets above all houses to prevent airplane impact damage.
    One of the problems when using comparisons is that not everyone will agree the comparison is valid or appropriate. For that reason I generally avoid using comparisons (though sometimes I do.
    Another problem is that after a comparison is used, others may use a comparison even less appropriate than the first. Now several people are questioning the validity of the other comparisons.

    Of course this does not just apply to Jim.
    As I said, sometimes, even I use them.
    And when I do, almost every time, someone guestions the comparison I used.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Luttrall View Post
    Here is a simple and accurate explanation of thermal expansion..

    http://www.google.com/url?sa=t&rct=j...,d.b2U&cad=rja
    Jim,

    One thing shown in that linked information that I did not think of when reading the Rheem information of thinking of the pressure being high enough to bulge out the bottoms of the water heater was the collapsing of flue the through the water heater - wonder if some of the sooting we see on gas WH that is thought of as backdrafting may be due to a partially collapsed flue?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Jerry -Your reading comprehension and understanding of codes really requires improvement.

    If you do not understand that GFCI is required by Code and dispute that fact ,you are far worse than I ever anticipated or did they change the Code last night?
    FYI - The NEC is not retro active and does not require bringing old components up to current standards.
    Jim,

    Your lack of reading comprehension should back up ...

    "If you do not understand that GFCI is required by Code" the code does not require GFCI protection (your statement) ... the code only requires GFCI protection in specific locations and conditions (my statement).

    Anther example of it:
    "FYI - The NEC is not retro active and does not require bringing old "

    You stated "GFCI protection is a widely accepted safety upgrade and is now required by Code." (your statement) and that is incorrect as upgrades are not required by code.

    In regard to your statement "FYI - The NEC is not retro active ... " you are only partially correct.

    The code IS retroactive to the extent that when a receptacle outlet in a location which NOW requires GFCI protection is REPLACED ... the replacement receptacle is REQUIRED to NOW have GFCI protection - that is "retroactive".

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    I have come across the need for expansion tanks on new construction homes twice this week. In both situations a PRV was installed (water pressure in our area without a PRV is around 130psi). In both cases the AHJ had just issued the CO on the new homes but neither had an expansion tank or valve. In both cases they had States brand tanks with their instruction/install manual sitting on the tanks. In both manuals on page 14 is a paragraph that states an expansion tank or device is required if the tank is installed in a closed system. The PRV makes it a closed system....

    Pretty simple if you ask me..

    So anyone know why Jim Abrams home inspection licensed was suspended? I recall seeing something about this not long ago..

    - - - Updated - - -

    I have come across the need for expansion tanks on new construction homes twice this week. In both situations a PRV was installed (water pressure in our area without a PRV is around 130psi). In both cases the AHJ had just issued the CO on the new homes but neither had an expansion tank or valve. In both cases they had States brand tanks with their instruction/install manual sitting on the tanks. In both manuals on page 14 is a paragraph that states an expansion tank or device is required if the tank is installed in a closed system. The PRV makes it a closed system....

    Pretty simple if you ask me..

    So anyone know why Jim Abrams home inspection licensed was suspended? I recall seeing something about this not long ago..

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    Ian
    This is a list of inspectors that said there needed to be an expansion tank installed on that WH
    Myself, post #1; Scott #2; Jerry #3; and Jim #41

    There was some discussion about other points. but not one person said an expansion tank was not needed on that water heater

    You didn't know, sometimes that happens.
    Accept it, learn from it, and be a better inspector because of it.

    People that are unwilling to learn from their mistakes are sure to repeat the mistake again.

    Rick
    I'm really not questioning the need for expansion tanks, the logic and data is pretty clear. And I thank all those who have provided links to very informative information. I'm troubled, however, by the differences in the related pressure readings and the plumber using something of an alarmist explanation and 'prop' to emphasize that need. Expansion tanks are not consistently installed here, neither in new construction or when installing a new tank so one does have to wonder if their benefit has real, true life application or is there an element of scare-mom gearing within the plumbing industry.

    I'd really be interested on any data, news reports etc. which clearly define that accidents, damage to property would not have occurred with expansion tanks installed.

    It's certainly not that I'm unwilling to learn (we could all do with that on a consistent basis) but at the same time like to have justifiable fact, not just urban legend, before I pass the information on to customers. All the links I have read supporting the use of ETs come from the manufacturers themselves, which makes me somewhat suspicious.

    I don't really think that four inspectors out of the many that read these posts is a particularly good assessment or recommendation.


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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Raymond Wand View Post
    To my knowledge not all manufactures require an expansion tank in my area, either electric or gas, and I don't think the building code up here requires it because I don't see them installed in new homes. Once again blanket statements don't always jive with what is or not required by geographic location.
    Expansion tanks are common here in new construction. Same water heaters, same country.
    Also there is a check valve on the supply line, and I suspect that requirement creates the need. Closed system, thermal expansion = expansion tank, or ocassionaly, an expansion valve with a discharge tube to a drain.

    What bugs me is the expansion tank hanging on PEX and plastic clamps, or sticking out sideways on soldered copper pipe, or similar. There is no requirement to support the tank?

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Jim, you have my original post there so you must have read it.

    The original pressure taken was 65psi. Nothing changed, the house was unoccupied, the WH was set to medium heat. At some point the thermocouple goes awry, WH fails to heat water and at two weeks after the first read a plumber is called for repairs. He takes his reading with his gauge from the same bib and gets a reading rising from 90 psi. leveling to 110 psi. The only difference now is that the WH is cranked to Max. Hot. Two hours later, now with the WH set to medium again the pressure at the same bib reads just under 65 psi and steady.

    What am I missing here, where is the dangerous condition that warrants thermal pressure adjustment? At no time did the TPR valve disharge though being 10 years old, I assume original to the WH, it could be faulty.

    Expansion tank installation in this area is a rarity, to say the least. Never seen one installed in new construction in the same water district and same zip code, so what makes this particular home unique? It's a regular tract home in the middle of an established residential estate.

    Should we, as Inspectors, recommend thermal tank installation as a matter of course, irrespective of pressure gauge reading?
    The issue is the thermal expansion which will happen EVERY TIME the water heater goes through recovery (i.e. totally cold water tank being heated to hot water).

    I suspect there is a pressure issue in your example regardless of the setting of the heater to MAX or lower temperatures. Yes, you will see higher pressures with higher temperatures but excessive pressure (over 80psi) will still happen even at a lower setting.

    The danger is NOT explosion (the TPR covers that) but the excessive pressure variations that can over time destroy a water heater and the water supply system of the house.
    Shortened water heater life is the most readily observable issue. Also, CO issues can result from collapsed flues on gas fired heaters.

    Once a valve of any kind (not just the TPR) in the closed side of the system is opened once the heater has satisfied the demand, the excess pressure is relieved and the system will once again resume the normal supply pressure.
    The pressure NEVER again climbs until cold water again fills the tank and is heated.
    So you may never notice a leaking TPR valve or other signs of over pressure since the pressure only exists until a valve in the closed system is opened.
    The TPR valve opens around 150 psi but is 120 or 140 psi acceptable in a system that is by code limited to 80psi? Not in my world.


    If a PRV (Pressure Reducing Valve), check valve, or other valve which limits the ability of the system to back flow excess water to the city main is installed, there is a need to have a thermal expansion device to protect the heater and the rest of the water supply system.

    ALL systems with storage type heater MUST have some sort of thermal expansion method. Most systems use the "open" system method to allow water to flow back to the city main. If the valving of the particular system prevents this method by creating a "closed" system, then another method of thermal expansion is needed, usually by installing a thermal expansion tank.

    The problem as I see it for inspectors is determining which systems have a PRV or other that necessitates a thermal expansion device. In areas with basements and exposed entrance pipes, a visual check should reveal this, but if the pipes are underground as they are here, it is a bit trickier.

    All new construction here is beginning to have these along with the PRV since the street pressures regularly exceed the 80 psi maximum.

    So do we as a matter of course recommend an expansion tank?
    For me, not unless I suspect there is a PRV installed.
    I have more than once checked pressures on neighboring houses to confirm higher street pressures than at the house I am inspecting, confirming a PRV even though I cannot see it.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Rick
    I'm really not questioning the need for expansion tanks, the logic and data is pretty clear. And I thank all those who have provided links to very informative information. I'm troubled, however, by the differences in the related pressure readings and the plumber using something of an alarmist explanation and 'prop' to emphasize that need. Expansion tanks are not consistently installed here, neither in new construction or when installing a new tank so one does have to wonder if their benefit has real, true life application or is there an element of scare-mom gearing within the plumbing industry.

    I'd really be interested on any data, news reports etc. which clearly define that accidents, damage to property would not have occurred with expansion tanks installed.

    It's certainly not that I'm unwilling to learn (we could all do with that on a consistent basis) but at the same time like to have justifiable fact, not just urban legend, before I pass the information on to customers. All the links I have read supporting the use of ETs come from the manufacturers themselves, which makes me somewhat suspicious.

    I don't really think that four inspectors out of the many that read these posts is a particularly good assessment or recommendation.
    The IRC requires thermal expansion device be provided. Is that a biased publication?

    You are not going to see any news reports because this is not a sudden impact story like a bomb going off. If thermal expansion issues cause the flue to collapse and become obstructed and thereby create a CO poisoning death, the news story is going to be a malfunctioning water heater that will be blamed on the installer and or manufacturer of the heater. An indepth study by the local TV news is not very likely, especially since half the inspectors and plumbers don't seem to grasp the issue. Discussing the nuances of PRV, TPR, check valves and thermal expansion tanks would have everyone flipping channels in pretty short order.

    I realize that the manufacturers of water heaters and valves have a vested interest in selling a $30 expansion tank with every heater but just because they can make a profit on a part does not mean they are wrong.

    Using the pressure gauge to sell an expansion tank just seems like a good educational tool. He could have just told them they needed a tank and walked away then "I told you so" when he is called out to replace a failed heater. He was actually saving the client money in the long run.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by John Kogel View Post
    What bugs me is the expansion tank hanging on PEX and plastic clamps, or sticking out sideways on soldered copper pipe, or similar. There is no requirement to support the tank?
    The requirements that I've seen are the installation instructions which have all shown the tanks hanging vertically from a tee in copper pipe, mounted vertically above a tee into the cold water inlet above the vertical body of the tee (not the side of the tee), and most make mention that the tanks need to be adequately supported for the weight of the tank and the water in the tank (in various and different wording).

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Thanks, Jerry. Good to know there is documentation.

    I call for a brace and a strap when I see them swinging on PEX pipe or sticking out horizontally.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

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    Default Re: Thermal expansion tank and pressure

    I know things vary regionally. I thought that most water companies were now installing backflow preventers. They are common in my area. Most houses here have the meters, PRV, BFP, installed inside the house so they are visible.

    Regarding PRVs, there are two types. One type allows backflow and one type does not. I have not tried to figure out how to tell the difference just by looking at them.

    On houses with wells I never see expansion tanks.


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    Default Re: Thermal expansion tank and pressure

    Jim,

    Your inability to comprehend even the simple things in codes never ceases to amaze me (I.e, you are in a downward flat spin) ... never mind - just remembered that I was feeding the Troll and that only encourages the Troll to continue ...

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    I would suggest to you all to attach a pressure gauge to your water lines, and observe first hand how much pressure is developed by thermal expansion.
    After doing so, maybe we can discuss this issue intelligently.
    Jim, the OPs question was really about is an expansion tank needed, not so much about the pressure.
    But lets go with the pressure.
    OP stated 65 psi on supply. After running the WH (remember the WH had been off) the pressure went to 110psi. Does not sound out of line.
    Tell you what, instead of all of us doing what you want.
    You do it.
    Start with cold water in the WH, connect the guage to drain bib on WH, CLOSE the cold water valve at the WH, be certian all faucets are off, fire up the WH on high, take a LONG nap, then report back and let us know.
    PS To get a really really accurate reading on the pressure gauge, plug the TPR valve.
    Oh yeah, there really is no need to let us know what happened, we'll just watch the news.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  52. #52
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Sorry Rick - You will not see it on the news .I have been through this process numerous times.
    In normal operating conditions the pressure rise is not excessive.
    The pressure and expansion tank are directly related. The expansion tank is designed to reduce pressure.

    Of course Jim, that is what an expansion tank is supposed to do, allow a place for the expansion of heated water, which will keep the pressure from rising to a dangerous level. But the OP DID NOT HAVE AN EXPANSION TANK. That is what his question was, should there have been an expansion tank. Because there not not an expansion tank, AND it was a closed system, an expansion tank was needed. If it was not a closed system an expansion tank would not have been needed.

    Closed system = PVR, BPA, or check valve is installed.
    Open system= PVR, BPA, and check valve is not installed
    .
    Closed system= Backpressure
    Open system= No backpressure

    Closed system= REQUIRED TO HAVE an expansion tank (or other)
    Open system= NOT REQUIRED to have an expansion tank. *
    * In my area, all new WHs (includes replacement) are required to have an expansion tank even on open systems.

    Closed system:
    With expansion tank= Good
    Without expansion tank = Bad

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  53. #53
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    I went through this a number of years ago with a plumbing inspector and ran pressure tests . The pressure increases due to thermal expansion were minimal.
    Please provide details on your testing, what was closed, what was not closed, starting water temperature, fully hot water temperature, starting pressure, fully hot pressure, thermal expansion tank, not thermal expansion tank ... you know, like a good old fashioned scientific experiment with data logging of temperature and pressure every 5 minutes, etc.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  54. #54
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    Jim, the OPs question was really about is an expansion tank needed, not so much about the pressure.
    But lets go with the pressure.
    OP stated 65 psi on supply. After running the WH (remember the WH had been off) the pressure went to 110psi. Does not sound out of line.
    Tell you what, instead of all of us doing what you want.
    You do it.
    Start with cold water in the WH, connect the guage to drain bib on WH, CLOSE the cold water valve at the WH, be certian all faucets are off, fire up the WH on high, take a LONG nap, then report back and let us know.
    PS To get a really really accurate reading on the pressure gauge, plug the TPR valve.
    Oh yeah, there really is no need to let us know what happened, we'll just watch the news.
    Rick and others seem to missing something.

    Altogether there were three plus reads of the pressure all from the same bib. The first at 65, the second by the plumber at 90-110 and the third by the homeowner (while on the telephone with me) was a shade over 60 psi. Three different gauges used. The plumber said his read indicated the need for an expansion tank could be an accurate assessment IF his gauge was true and offered to install one for $385. Just for arguments sake lets assume his gauge was faulty and off by 30lbs (I have one on my desk right in front of me with a non-pressurized base read at 32 - not 0). This would mean that all three pressure readings would be in the 60 -75 psi range and certainly not excessive. (Everyone is assuming the plumber is honest, his gauge is accurate and using his 'read' to justify the need for an expansion tank).

    Other than an expansion tank being an additional safety device, is the need still indicated under those circumstances? I understand the position of the proponents - install one whether you need it or not and I see the value of that, just not in it's entirety.

    Furthermore, ETs need to be both charged appropriately for incoming pressure and sized accordingly. I understand typical charging methods are by way of a basic schrader bike wheel type valve on the tank and a hand held bike pump - simple enough. However, once installed, maintenance and pressurization is left to the homeowner. If internal pressure depreciates over time, doesn't that mean the tank is less effective or even non-functional?

    Wouldn't you get a better read of the WH thermal expansion by using the WH drain spigot, rather that a cold water supply spigot - as in this case?


  55. #55
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Rick and others seem to missing something.
    I don't know what you think I'm missing.

    Quote Originally Posted by Ian Page View Post
    Altogether there were three plus reads of the pressure all from the same bib. The first at 65, the second by the plumber at 90-110 and the third by the homeowner (while on the telephone with me) was a shade over 60 psi. Three different gauges used. The plumber said his read indicated the need for an expansion tank could be an accurate assessment IF his gauge was true and offered to install one for $385. Just for arguments sake lets assume his gauge was faulty and off by 30lbs (I have one on my desk right in front of me with a non-pressurized base read at 32 - not 0). This would mean that all three pressure readings would be in the 60 -75 psi range and certainly not excessive. (Everyone is assuming the plumber is honest, his gauge is accurate and using his 'read' to justify the need for an expansion tank).
    No. In your OP, you stated it had a valve in the water line.This tells me it is a closed system A closed system needs (is required) an expansion tank. Using the pressure gauge was just to show the HO.

    Quote Originally Posted by Ian Page View Post
    Other than an expansion tank being an additional safety device, is the need still indicated under those circumstances? I understand the position of the proponents - install one whether you need it or not and I see the value of that, just not in it's entirety.

    Furthermore, ETs need to be both charged appropriately for incoming pressure and sized accordingly. I understand typical charging methods are by way of a basic schrader bike wheel type valve on the tank and a hand held bike pump - simple enough. However, once installed, maintenance and pressurization is left to the homeowner. If internal pressure depreciates over time, doesn't that mean the tank is less effective or even non-functional?
    If the tank leaks down that means the diaphragm is ruptured (replace the expansion tank) and not very likely, or more likely, the schrader valve is leaking (replace schrader valve and re-pressurize with air).


    Quote Originally Posted by Ian Page View Post
    Wouldn't you get a better read of the WH thermal expansion by using the WH drain spigot, rather that a cold water supply spigot - as in this case?
    No, it would be the same at any/ every point in the water system.

    When it is a closed system (PVR, Backflow preventer, or check valve is installed), it needs (is required) an expansion tank (or other).
    If it is an open system, it is not required to have an expansion tank (unless by code, such as in my area).

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  56. #56
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Jim Abram View Post
    Rick - Massachusetts and other areas where I work have not adopted the plumbing section of the IRC .That is why they are not required here and are rarely installed.
    Can you explain this?
    bold added

    248 CMR 10.00: Uniform State Plumbing Code - (continued)
    Where water meters or metering devices with check valves are installed, which can create a potential hazard or nuisance due to thermal expansion, a thermal expansion tank shall be installed as close as possible to the water meter or metering devices.
    The thermal expansion tank

    or this

    (e) Cold Water Supply.
    2. .... A thermal expansion tank may be required or necessary on any cold water supply system where installation of Backflow Prevention Devices or pressure reducing valves would create a closed system and constitute an operating hazard or nuisance.


    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  57. #57
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Rick Cantrell View Post
    Can you explain this?
    bold added

    248 CMR 10.00: Uniform State Plumbing Code - (continued)
    Where water meters or metering devices with check valves are installed, which can create a potential hazard or nuisance due to thermal expansion, a thermal expansion tank shall be installed as close as possible to the water meter or metering devices.
    The thermal expansion tank

    or this

    (e) Cold Water Supply.
    2. .... A thermal expansion tank may be required or necessary on any cold water supply system where installation of Backflow Prevention Devices or pressure reducing valves would create a closed system and constitute an operating hazard or nuisance.
    Quote Originally Posted by Jim Abram View Post
    Expansion tanks are viewed as optional .
    Yeah, now I see

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  58. #58
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    Wink Re: Thermal expansion tank and pressure

    I spoke with the new homeowner earlier today and discussed the expansion tank issue. They reminded me that during the service call under the Home Warranty, the plumber said that failing to install an expansion tank after his recommendation would, in all likelihood, void any future plumbing related claims under the warranty. Not really buying into that but insurance companies are impossible to argue with.

    I told them to find another plumber, install a tank - and be a trendsetter in their neighborhood, just in case.

    Rick what you were missing is, IMO, the plumber's suspiciously high pressure reading in order to garner work. Say it ain't so....nah, wouldn't do that he's one of the honest good guy types. How would he convince the homeowner without his high pressure reading.

    Conversation would go something like this, "Okay, so the work is done, the water heater's functioning as it should, everything looks great - pressure's fine, though it does increase as the water gets hotter, which is perfectly normal, I think. Might also be because you have a kitchen. Have you thought about installing a thermal expansion tank? They're really cool. No one else in the neighborhood has one, you could be the first. You might get a few more months of service out of your aging Water Heater, which i can also replace, or you might not. Oh, and I can install it today - got one on my truck right here, nice shiney blue to match your eyes...."


  59. #59
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    I spoke with the new homeowner earlier today and discussed the expansion tank issue. They reminded me that during the service call under the Home Warranty, the plumber said that failing to install an expansion tank after his recommendation would, in all likelihood, void any future plumbing related claims under the warranty. Not really buying into that but insurance companies are impossible to argue with.

    I told them to find another plumber, install a tank - and be a trendsetter in their neighborhood, just in case.

    Rick what you were missing is, IMO, the plumber's suspiciously high pressure reading in order to garner work. Say it ain't so....nah, wouldn't do that he's one of the honest good guy types. How would he convince the homeowner without his high pressure reading.

    Conversation would go something like this, "Okay, so the work is done, the water heater's functioning as it should, everything looks great - pressure's fine, though it does increase as the water gets hotter, which is perfectly normal, I think. Might also be because you have a kitchen. Have you thought about installing a thermal expansion tank? They're really cool. No one else in the neighborhood has one, you could be the first. You might get a few more months of service out of your aging Water Heater, which i can also replace, or you might not. Oh, and I can install it today - got one on my truck right here, nice shiney blue to match your eyes...."
    I haven't read all of the posts but I get the impression that some believe the pressure is related to the temperature only. The plumbers demonstration was correct in showing that the water pressure increased as the temperature of the water increased. The pressure will drop to the supply pressure as soon as any one of the fixtures uses water and relieves the excess pressure. The water can be at any temperature below boiling (which is determined by the pressure) and will be at the supply pressure. The main reason for a thermal expansion relief device is to relieve the pressure developed during the increase caused by heating cold water without being used by a fixture, which happens mostly when turning the temperature back up after vacation etc.

    If this has been stated in previous posts forgive me; just trying to help if I can.

    The beatings will continue until morale has improved. mgt.

  60. #60
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Vern Heiler View Post
    I haven't read all of the posts but I get the impression that some believe the pressure is related to the temperature only. The plumbers demonstration was correct in showing that the water pressure increased as the temperature of the water increased. The pressure will drop to the supply pressure as soon as any one of the fixtures uses water and relieves the excess pressure. The water can be at any temperature below boiling (which is determined by the pressure) and will be at the supply pressure. The main reason for a thermal expansion relief device is to relieve the pressure developed during the increase caused by heating cold water without being used by a fixture, which happens mostly when turning the temperature back up after vacation etc.

    If this has been stated in previous posts forgive me; just trying to help if I can.

    Thank you Vern...and that's exactly what the plumber should have told the homeowners, instead of leaving them with the impression that the WH was about to blow at any second.


  61. #61
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    Default Re: Thermal expansion tank and pressure

    I think everyone is missing the point that the water heater manufacturers are the ones requiring the expansion devices if the tank is on a closed system!!! The codes might require it as well, but in my book the manufacturers requirements get priority.....

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  62. #62
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Scott Patterson View Post
    I think everyone is missing the point that the water heater manufacturers are the ones requiring the expansion devices if the tank is on a closed system!!! The codes might require it as well, but in my book the manufacturers requirements get priority.....
    Scott
    I'm sure some do, perhaps many, but checking specifications on several water heaters on line, gas and electric, none specified the installation of an expansion tank was a requirement. I looked at B&W, Rheem?and Whirlpool. Maybe in the installation literature.


  63. #63
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Scott
    I'm sure some do, perhaps many, but checking specifications on several water heaters on line, gas and electric, none specified the installation of an expansion tank was a requirement. I looked at B&W, Rheem?and Whirlpool. Maybe in the installation literature.
    Yes, it is in every single install manual or guideline I have seen that comes with the tank.. In the most resent States manual I'm pretty sure it is on page 14...

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  64. #64
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Scott Patterson View Post
    The codes might require it as well, but in my book the manufacturers requirements get priority.....
    The codes require the installation to meet code AND manufacturer's installation instructions - and the most restrictive of each takes precedence over the less restrictive.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  65. #65
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    Default Re: Thermal expansion tank and pressure

    Quote Originally Posted by Ian Page View Post
    Scott
    I'm sure some do, perhaps many, but checking specifications on several water heaters on line, gas and electric, none specified the installation of an expansion tank was a requirement. I looked at B&W, Rheem?and Whirlpool. Maybe in the installation literature.
    You keep wanting to find a way out.
    You say it's in the manual, show me.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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