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  1. #1
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    Default water heater temp

    Do you ever recommend turning the water heater thermostat up?

    I got a temperature reading of 105 today. I know it's on the low side but my main concern is that this water heater is also charged with the task of supplying hot water to the AquaTherm furnace for heat exchange. It's a 38 gallon gas water heater.

    Would you suggest that they bump the water heater therm setting up?

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  2. #2
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    Default Re: water heater temp

    It's certainly worth mentioning that it's lower than typical. Maybe a mention that 120-125 is the standard setting.


  3. #3
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    Default Re: water heater temp

    What about the installation of the plumbing regarding the teamwork between the water heater and furnace coil? Is there any special requirements there? Perhaps a mixing valve for the hot water supply to the house fixtures?

    That way, the water heater gets turned up higher to be able to get the furnace coil hoter, then the mixing valve takes the edge off the hot water to prevent persons from being burned at the fixtures.

    I didn't dream this up. Someone mentioned it to me. I'm wondering if there is truth to the idea. I"m wondering if the system I sw today is installed right.

    I'm thinking, 105 degree water to the furnace coil is not going to satisfy the heating demand in the dead of winter around here.


  4. #4
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    Default Re: water heater temp

    Quote Originally Posted by John Dirks Jr View Post
    I got a temperature reading of 105 today.

    Technically speaking, that house does not have "hot water", which is a requirement.

    From the 2006 IRC.
    - HOT WATER. Water at a temperature greater than or equal to 110°F (43°C).


    Jerry Peck, Construction / Litigation Consultant
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  5. #5
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    Default Re: water heater temp

    Quote Originally Posted by Jerry Peck View Post
    Technically speaking, that house does not have "hot water", which is a requirement.

    From the 2006 IRC.

    - HOT WATER. Water at a temperature greater than or equal to 110°F (43°C).
    Another note having the water temperature set that low is asking the tank to be a breading ground for legionaries disease.
    Here is from the Illinois code book:

    Section 890.120 Definitions

    "Hot Water": Water at a temperature of not less than 120°F.

    "Tempered Water": Water ranging in temperature from 85°F to, but not including, 120°F.


  6. #6
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    Default Re: water heater temp

    I read some stuff recently (can't remember where) about the disease thing as it pertains to water heater temps. There's a fine line between what is considered safe temperature to prevent burns and safe to prevent bacteria growth. Look for more definition and controversy on this in the next few years.

    On a related note, a couple times in the last few months I've encountered the tub/showers and stall showers in new houses having very lukewarm water at the full 'hot' setting. From piecing together several scraps of info it seems the builders/plumbers are purposely setting the temp ridiculously low (around 90 degrees). Then, when the buyers complain, they have to sign a disclaimer that says they asked for the water to be turned up (mixing valves adjusted) so the builder has no liability for leaving it too high.

    It seems ridiculous but given the state of our legal system, nothing would surprise me.


  7. #7
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    Default Re: water heater temp

    Quote Originally Posted by Matt Fellman View Post
    I read some stuff recently (can't remember where) about the disease thing as it pertains to water heater temps. There's a fine line between what is considered safe temperature to prevent burns and safe to prevent bacteria growth. Look for more definition and controversy on this in the next few years.

    On a related note, a couple times in the last few months I've encountered the tub/showers and stall showers in new houses having very lukewarm water at the full 'hot' setting. From piecing together several scraps of info it seems the builders/plumbers are purposely setting the temp ridiculously low (around 90 degrees). Then, when the buyers complain, they have to sign a disclaimer that says they asked for the water to be turned up (mixing valves adjusted) so the builder has no liability for leaving it too high.

    It seems ridiculous but given the state of our legal system, nothing would surprise me.
    Setting the shower/tub temperature that low would also violate plumbing codes.
    Here is the part in the Illinois Plumbing code which points out the max setting let me find the mininum part addressed in the code Underlining added by me which points out the max setting let me find the mininum part addressed in the code:

    Section 890.690 Shower Receptors and Compartments

    b) Water Temperature Safety. All shower compartments and shower-bath combinations shall be provided with an automatic safety water mixing device to prevent sudden unanticipated changes in water temperature or excessive water temperatures. The automatic safety water mixing device shall comply with ANSI/ASSE 1016-1996, in accordance with Section 890.210, and be designed with a maximum handle rotation limit/stop, or comply with ASSE 1017-1998, in accordance with Section 890.210. The automatic safety water mixing device shall be adjusted to a maximum setting of 115° F at the time of installation. The temperature of mixed water provided to multi-shower units or gang showers shall be controlled by a master automatic safety water mixing device or the mixed water temperature for such showers shall be individually regulated by automatic safety mixing valves for each shower unit. A hot water heater thermostat shall not be an acceptable alternative water temperature control device.


  8. #8
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    Default Re: water heater temp

    I swore I recall learning that the minimum temperature setting on a tub/Shower mixing valve was to be set no lower than 110º F. I must have been mistaken, I can not find it anywhere in the Illinois code book. Guess its just the maximum of 115º F

    I did find some good reading material about the safety of having the water heater set to a proper temperature and making sure there is protection against scalding at the fixtures within the building. http://www.ciph.com/Downloads/codesA...onAnalysis.pdf


  9. #9

    Default Re: water heater temp

    On a related note, a couple times in the last few months I've encountered the tub/showers and stall showers in new houses having very lukewarm water at the full 'hot' setting. From piecing together several scraps of info it seems the builders/plumbers are purposely setting the temp ridiculously low (around 90 degrees). Then, when the buyers complain, they have to sign a disclaimer that says they asked for the water to be turned up (mixing valves adjusted) so the builder has no liability for leaving it too high.
    I find tub/ shower mixing valves set to luke warm all of the time in new construction. I tell them to make necessary adjustments. I do one year home warranty inspections where the occupants set the heater to "hot" and the showers are warm/ hot, while everything is else is "scalding hot".

    Last edited by Brandon Whitmore; 04-04-2009 at 10:18 AM.

  10. #10
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    Default Re: water heater temp

    Jerry is correct (no surprise there)
    This is the code from the 2006 International Property maintenance code
    Bold added

    505.4 Water heating facilities.
    Water heating facilities shall

    be properly installed, maintained and capable of providing an
    adequate amount of water to be drawn at every required sink,
    lavatory, bathtub, shower and laundry facility at a temperature
    of not less than 110°F (43°C).Agas-burning water heater shall
    not be located in any bathroom, toilet room, bedroom or other
    occupied room normally kept closed, unless adequate combustion
    air is provided. An approved combination temperature and
    pressure-relief valve and relief valve discharge pipe shall be
    properly installed and maintained on water heaters.





    ' 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: water heater temp

    Temps in excess of 120 are scalding hazard. Also an energy waste - the water stays hot 24/7. I practice and suggest temp to be set so that bathing does not require mixing cold water mix. (It is about 113)

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  12. #12
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    Default Re: water heater temp

    Quote Originally Posted by Richard Stanley View Post
    Temps in excess of 120 are scalding hazard. Also an energy waste - the water stays hot 24/7. I practice and suggest temp to be set so that bathing does not require mixing cold water mix. (It is about 113)
    Here is a blurb from the PDF I posted about water temperature safety.

    WHY WATER HEATERS CAN’T BE RELIED UPON TO CONTROL AND LIMIT FINAL TEMPERATURE


    Although water heater manufacturers are recommending that installers set thermostats at 120 degrees F., the plumbing engineering community continues to recommend hot water systems be designed with higher temperatures to reduce the threat of Legionella. Additionally, water heaters set at lower temperatures reduce the capacity to deliver hot water. As such, water heaters will likely be set at temperatures above 120 degrees F., which means that hot water systems will continue to store and deliver water at potentially scalding temperatures.


    Water heater thermostats were never intended to provide precise limits and controls on hot water temperatures. To illustrate this point, the thermostat dial calibration test of ANSI Z21.10.1-1998, which is the applicable standard for gas-fired water heaters, allows the temperature to vary 10 degrees above or below the thermostat setting. Additionally, the maximum temperature limit test of ANSI Z21.10.1 allows the outlet water temperature to rise 30 degrees F. above the thermostat setting. This provision accounts for the phenomenon known as “stacking” or “layering”. Stacking or layering occurs when hot water gathers at the top of the heater due to recurring short duration heating cycles caused by frequent number of small quantity hot water uses. Although the above example addresses gas water heaters, this

    phenomenon can also occur in other types of storage water heaters.
    Now to bring up another point. When I went to my continued education class to renew my plumbing license, the code officials where talking about the required temperature the water heaters are set at may get raised to 140ºF and they will require a whole house thermal mixing valve installed at the water heater. Also they are going to raise the standards on the temperature and pressure balancing valves used on the showers.


  13. #13
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    Default Re: water heater temp

    Quote Originally Posted by Brandon Whitmore View Post
    I find tub/ shower mixing valves set to luke warm all of the time in new construction. I tell them to make necessary adjustments. I do one year home warranty inspections where the occupants set the heater to "hot" and the showers are warm/ hot, while everything is else is "scalding hot".
    Too funny Brandon, recently I was debating this issue with a builder and he claimed his plumber left it low (90-ish) because of the scalding potential. Without even reading up on it I told him that ultimatley the homeowner would just crank up the water heater and get scalding water from the faucets in order to get hot water at the shower.

    To me the differential is what's dangerous. People are capable of spinning the knob on their water heater. Most aren't capable of taking the mixing valve apart.


  14. #14
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    Default Re: water heater temp

    Quote Originally Posted by Ron Hasil View Post
    Now to bring up another point. When I went to my continued education class to renew my plumbing license, the code officials where talking about the required temperature the water heaters are set at may get raised to 140ºF and they will require a whole house thermal mixing valve installed at the water heater. Also they are going to raise the standards on the temperature and pressure balancing valves used on the showers.


    Ron,

    That is something which, in my opinion, they should have done years ago, and they should required the design of the valve be as fail safe as possible with failure causing the valve to 'go cold' instead of fail to hot.

    Kind of like a car engine thermostat - they are designed to be normally closed then open when heated, and when the thermostat sticks or fails it is almost always in the closed position (which in the case of the car engine causes the engine to overheat, whereas in a house it would cause only cold water to flow).

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

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    Default Re: water heater temp

    Quote Originally Posted by Jerry Peck View Post
    Ron,

    That is something which, in my opinion, they should have done years ago, and they should required the design of the valve be as fail safe as possible with failure causing the valve to 'go cold' instead of fail to hot.

    Kind of like a car engine thermostat - they are designed to be normally closed then open when heated, and when the thermostat sticks or fails it is almost always in the closed position (which in the case of the car engine causes the engine to overheat, whereas in a house it would cause only cold water to flow).
    Jerry one of the devices they might require is when the temperature raises above 115º F it will bring the water flow down to less than .2 gallons a minute and will auto reset once the temperature returns to a safe level.


  16. #16
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    Default Re: water heater temp

    Quote Originally Posted by John Dirks Jr View Post
    What about the installation of the plumbing regarding the teamwork between the water heater and furnace coil? Is there any special requirements there? Perhaps a mixing valve for the hot water supply to the house fixtures?

    That way, the water heater gets turned up higher to be able to get the furnace coil hoter, then the mixing valve takes the edge off the hot water to prevent persons from being burned at the fixtures.

    I didn't dream this up. Someone mentioned it to me. I'm wondering if there is truth to the idea. I"m wondering if the system I sw today is installed right.

    I'm thinking, 105 degree water to the furnace coil is not going to satisfy the heating demand in the dead of winter around here.
    John,
    I had a similar situation a few years back in a church. They required 150 degrees for the commercial dishwasher and contacted me to install a water heater just for the dishwasher, as someone in the building would turn the only water heater up to satisfy the demand of the dishwasher, but...they also had a school and if they forgot to turn the temp back (yes it did happen) the water is a little (understatement) too hot to wash your hands. Instead of installing an additional water heater I turned the temp up on the water heater they already had and I installed a tempering valve to supply the rest of the building and just had the Hot Hot water going only to the dishwasher.
    Lee


  17. #17
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    Default Re: water heater temp

    Quote Originally Posted by Lee Nettnin View Post
    John,
    I had a similar situation a few years back in a church. They required 150 degrees for the commercial dishwasher and contacted me to install a water heater just for the dishwasher, as someone in the building would turn the only water heater up to satisfy the demand of the dishwasher, but...they also had a school and if they forgot to turn the temp back (yes it did happen) the water is a little (understatement) too hot to wash your hands. Instead of installing an additional water heater I turned the temp up on the water heater they already had and I installed a tempering valve to supply the rest of the building and just had the Hot Hot water going only to the dishwasher.
    Lee
    Using a water heater for space heating is required by Illinois code to have a thermostatic mixing valve to ensure that the water temperature does not exceed 120º F Also restaurants that use one common water heater to supply the 150º + F water for the dish washer must also have a thermostatic mixing valve to provide water temperatures not to exceed 120º F to the rest of the plumbing fixtures. Here is the part from the Illinois plumbing code.

    Section 890.1220 Hot Water Supply and Distribution

    9) Water Heaters Used for Space Heating. Any water heater to be used for space heating, in addition to hot water supply, must conform to ANSI Z21.10.1a-1991, shall be constructed for continuous use, and the piping for space heating shall be conducted to a proper terminal heating device.

    A) A thermostatic mixing valve, conforming to ASSE 1017-1999, shall be installed on the hot water line to the plumbing fixtures. (The mixing valve shall be set to prevent temperatures exceeding 120°F from reaching the plumbing fixtures.)

    B) A single check valve shall be installed in the cold water line supplying the water heater. (This will prevent hot water backing up from the heating unit to the plumbing fixtures.)

    C) A properly sized and approved expansion tank shall be located on the outlet side of the check valve in the water heater's cold water supply with no shut-off valve between the heater and expansion tank.

    D) Valves (manual, automatic) supplying hot water to the heat transfer unit for space heating shall have a minimum of a ⅛ inch orifice. (This will prohibit potable water from standing in the heat transfer unit when not in use.) This does not prohibit full shut off/isolation valves on either side of the pump within a heat transfer unit, as needed, to permit the servicing of the pump.

    E) The water heater instructions shall have a statement specifying that piping and components connected to the water heater for the space heating application shall be suitable for use with potable water, and the water heater shall not exceed a developed length of more than 25 feet from the heating coil.

    F) A statement specifying that toxic chemicals, such as those used for boiler treatment, shall not be introduced into the potable water used for space heating shall be included in the instructions. A label with the following words shall be firmly attached to any water heater used for space heating: "DO NOT INJECT TOXIC MATERIALS INTO THIS TANK."

    G) A statement specifying that a water heater which will be used to supply potable water shall not be connected to any heating system or components previously used with a non-potable water heating appliance shall be included in the installation instructions.

    H) Each water heater shall bear a statement on the rating plate as follows: "SUITABLE FOR POTABLE WATER HEATING AND SPACE HEATING."


    Last edited by Ron Hasil; 04-08-2009 at 07:11 AM.

  18. #18
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    Default Re: water heater temp

    The India Gomez case is probably the gold standard in scalding liability. $15 million.

    http://www.homeinspector.org/resourc...mbing-News.pdf

    To reduce liability, report temp over 120, and put warning that hot water can scald in your disclaimer language. And recommend tempering valves anyway no matter what.


  19. #19
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    Default Re: water heater temp

    I have found several water heaters lately that have the thermostats set very low from the factory. I imagine this is being done for reasons of legal responsibility if someone would get burned. The factory could say that there policy is to set the tanks at 90 degrees or whatever. The code here in Ohio requires that the water temperature at the tub or shower faucet be between 110 and 120 degrees. A minimum of 120 degrees is required at the kitchen faucet and the maximum that is allowed to enter the drain piping is 140 degrees. In Ohio even tub faucets without a shower head, i.e. soaker tubs and whirlpools, are required to have a temperature adjustment device which limits the temp to 110-120.


  20. #20
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    Default Re: water heater temp

    When it is all said and done the home owner will decide what the temp will be. I suggest that as an inspector we have a duty only to report what we find and inform the owner or client that there are local and state standards that apply.
    In South Carolina the manufactuer is the guiding principal and we have only the responsibility to inform the client of the current Temp. setting. Beyond that you can leave yourself open for Legal issues.
    I am a firm believer that following the Standards and practices of your state is the best course of action. My attorney and Insurance company agree.
    As a contractor ( plumber,eletrician etc ) you may need to do more but again I would be cautious and stick to Standards and Practice for you Local.


  21. #21
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    Default Re: water heater temp

    Quote Originally Posted by Gary wellborn View Post
    I am a firm believer that following the Standards and practices of your state is the best course of action. My attorney and Insurance company agree.

    Gary,

    On this board you will only find a very few of you minimum type inspectors, ALMOST ALL OF US on this board recognize that the SoP are MINIMUMS which one must not go below, but which one SHOULD exceed to their level of knowledge.

    Welcome to THE inspectors board ... but be forewarned that almost everyone here does not agree with you (there are, of course, a couple of exceptions).

    Learning what you SHOULD be doing above and beyond your SoP, this is the place to be.

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

  22. #22
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    Default Re: water heater temp

    [quote=Matt Fellman;79483]
    On a related note, a couple times in the last few months I've encountered the tub/showers and stall showers in new houses having very lukewarm water at the full 'hot' setting. From piecing together several scraps of info it seems the builders/plumbers are purposely setting the temp ridiculously low (around 90 degrees).

    This happened to me several years ago, when my last WH was installed. The plumber set it at 104. I had to BEG for 109. He wouldn't set it any higher.


  23. #23
    archivoyeur's Avatar
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    Default Re: water heater temp

    Quote Originally Posted by Ron Hasil View Post
    {...}from the Illinois plumbing code.

    Section 890.1220 Hot Water Supply and Distribution

    9) Water Heaters Used for Space Heating. Any water heater to be used for space heating, in addition to hot water supply, must conform to ANSI Z21.10.1a-1991, shall be constructed for continuous use, and the piping for space heating shall be conducted to a proper terminal heating device. { ... }

    D) Valves (manual, automatic) supplying hot water to the heat transfer unit for space heating shall have a minimum of a ⅛ inch orifice. (This will prohibit potable water from standing in the heat transfer unit when not in use.) This does not prohibit full shut off/isolation valves on either side of the pump within a heat transfer unit, as needed, to permit the servicing of the pump.
    {...}
    G) A statement specifying that a water heater which will be used to supply potable water shall not be connected to any heating system or components previously used with a non-potable water heating appliance shall be included in the installation instructions.
    My office designs potable water and heating water as two separate systems, or so that heating water will never mix with potable water.


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