Thread: water heater with hot water shut off valve

hey all

first time i have ever seen this. both cold and hot water on 2004 water heater have shut off valves. what happens if someone shuts off the hot. don't think i want to be around if that happens. what do you think

cvf

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They would have to shut off both valves, the T&P valve would have to fail and the thermostat keeps on cooking the water past a safe temperature, for it to be dangerous.

Most codes do not specifically say a valve on the hot water side is prohibited. Like the Illinois code, but the Illinois code does reference a diagram in the code book which it does not show a valve on the hot side. So the plumbing inspectors around here interpret the diagram as the code saying valves on the hot side is not allowed.

So my best advice is to call the city that water heater is in and talk to the plumbing inspector to see if it is allowed or not.

What is the difference btw closing the hot water stop valves at the individual fixtures and having one central one at the tank? If it is an open system, the grid will buffer it. If someone closes both hot and cold, the TPR will buffer it. I know of no prohibition by any mfr., code or std. but as Ron said you may have a local prohibition. Just because a drawing fails to include one is not grounds to prohibit them. Prohibitions must be clearly stated in the code. Everything is 'approved' except where expressly prohibited or prescribed by code.

In your pic CVF, it appears you have an expansion tank meaning a closed system. In that case, you would still have the tank and TPR to absorb expansion so what's to worry?

The expansion tank should be between the cold water shutoff and the water heater.
No problem with having a shutoff on the hot water discharge side

The Illinois Plumbing code uses lots of drawings as reference to the code. It is left out for a reason. As you said if both hot and cold are off the TPR should open. What if someone in their wisdom capped the TPR?

What if there is a check valve or a backflow prevention device is installed on the cold inlet side, and they close the hot valve?

Have a look at what happened at Avon High School with a 5 gallon electric water heater with its T&P Valve capped. Avon High School Hot Water Heater Explosion – Final Report - MasterPlumbers.com PlumbNews There are many other water heater explosions I can link to. I think this should get the point across.

The less ways you give people to isolate the tank from the plumbing system, will help prevent it from exploding.

HEre is another one where 7 got killed and 36 injured. http://www.combustionsafety.com/secu...cer_lesson.pdf

I do not take water heaters lightly.

Ron, these are tragic but I fail to see how putting a shutoff on the hot water side of the WH relates to either of these cases. You claim the first one had a capped TPR--where does it say this? Even so, what does that have to do with a shutoff on the hot side? If this one blew without a shutoff on the hot then what difference would it make? I mean, negligence in installation and service cannot be cured by codes. The 4 recommendations for preventing this reoccurring do not affect a hot water shutoff. They relate to common sense responsibility issues.

If you want to talk about hazards and exposure, let me take you into virtually every building that has combustion venting and I'll show you people at risk, not just of dying but being made ill by bad installations and lack of qualified inspection and maintenance.

If I cannot confirm a TPR is less than 5 yrs old, I replace it and hope they reimburse me. I trip the test lever on all pressure reliefs and hope they compensate me when they fail to re-seat themselves. I include replacement of these safety controls on all repairs to boilers and WHs. However, the case against shutoffs on the hot side has not been made. These tanks blew without a hot shutoff so what's the difference? yes, we need better inspections, training, etc. but who's going to mandate it and who's gonna pay for it? The only way we're getting backflow compliance is by the water company threatening to shut off service for non-compliance but that is only being enforced in commercial and industrial applications around here inspite of the EPA mandate.

I can make a case for having annual WH and boiler inspections in residences but I can make a stronger case for venting inspection and testing because it represents a far greater threat. Until then, we fill continue to blow ourselves up and fumigate our homes.

Sorry I got my water heater explosions mixed up. This one just had a failed T&P valve. They did have issues with a breaker tripping, which they kept on resetting, in this case.

Point is if you add more valves which can cause a closed system, you are adding more potential for a catastrophic failure.

You know the 2003 and newer gas water heaters have a sealed type combustion chamber. Where the combustion air is drawn through a special vent port on the heater, through a ceramic screen at the bass of the heater then burned. The ceramic screen is to prevent any flammable vapors from igniting outside of the burn chamber of the water heater. These heaters are called FVIR (Flammable Vapor Ignition Resistant ) These where made mandatory that all 30, 40 and 50 gallon gas fired water heaters as of July 1, 2003 are equipped with an FVIR system. The reason is not everyone followed the safety sticker on the sides of water heaters, which said not to store any flammable liquids such as gas, paint, paint thinners and such near or around the water heater. Only a handful of people have done this but it was enough for the the government to mandated that all 30, 40 and 50 gallon water heaters have an FVIR system to help people prevent blowing themselves up.

So I do not see it far fetched that some codes may say do not install a shut off valve on the outlet of the water heaters.

The Illinois code may not point it out specifically but the Chicago code does.

18-29-503.1.1 Shut-off valves Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only.

hey all

thanks for the replies--city inspector said--he never sees it either, but if there is a tpr-no problem--he hopes.

cvf

Originally Posted by Bob Harper

What is the difference btw closing the hot water stop valves at the individual fixtures and having one central one at the tank?
.
Prohibitions must be clearly stated in the code.

"Clearly" stated is right.

Originally Posted by Ron Hasil

The Illinois code may not point it out specifically but the Chicago code does.

18-29-503.1.1 Shut-off valves Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only.

Okay, so I am now back to Bob's question as that was my first question, and I am also at the Illinois code - which prohibits the fixture shut off valves, so I guess all hot water plumbing in Illinois is re-circulating ... ?

Every single fixture shut off valve for the hot water to the fixture that I have ever seen has been ... (drum roll please) ... on the hot water outlet side of the water heater. That certainly violates this: "Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only".

If it is not Ok in Illynoize to put a shutoff for the water heater on the outlet side, how far down the piping are you allowed to install a shutoff? What if I want to make a run 40 feet down the length of the house to a manifold where I can shut off all the hot water risers from one point? Is that prohibited?

Ok, at what point is it ok to to install a shutoff at the fixture but not too close to the WH outlet? What is the cross-over point? Where the individual risers branch off to the individual fixtures?

Originally Posted by Bob Harper

If it is not Ok in Illynoize to put a shutoff for the water heater on the outlet side, how far down the piping are you allowed to install a shutoff? What if I want to make a run 40 feet down the length of the house to a manifold where I can shut off all the hot water risers from one point? Is that prohibited?

Ok, at what point is it ok to to install a shutoff at the fixture but not too close to the WH outlet? What is the cross-over point? Where the individual risers branch off to the individual fixtures?

I'm trying to figure out the same thing, given that water does not compress ... if the pipes are full of water, the pressure build-up will be the same regardless where the valve is located at (well, almost the same regardless ... there may be some hydro-static pressure loss per foot - so your question is pertinent: how far must the valves be?).

Ron,
Thank you for the two examples. Nightmare.
Combustion Safety's comment on the investigation in Okla. was a bit fuzzy: what precisely do they mean by:
Item 2. Testing safety operating limits.
Item 3. Verifying proper equipment lights off.

I think i know what they mean but i'm not sure.

Ron's Illinois Code quote is: "... for water heaters ..."

Perhaps, under the Illinois Code,
isolators on the hot side are considered to be for fixtures only, and would not refer to the water heater?

However, as Jerry and Bob noted, the wording does not develope it's meaning.

Originally Posted by Ron Hasil

The Illinois code may not point it out specifically but the Chicago code does.

18-29-503.1.1 Shut-off valves Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only.

They make the assumption all think in the same manor. Shut off next to tank.
But is it stated anywhere the distance to valve as a min or max distance?

If you have a HW tank in a bathroom and the distance to the fixture shutoff valve is 18 inches, is it then in violation to the code in IL.

Originally Posted by Ron Hasil

18-29-503.1.1 Shut-off valves Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only.

Shutoff valve FOR the water heater, not shutoff valve for a fixture. I think that there is the difference.

Apparently Pascal's law is not valid in Illinois .

At what distance does a valve become one for the fixture as opposed to the WH?

Why does it hurt being located close to the WH but not at the fixture?

What about intermediate shutoffs? At what point do they present a problem?

I can't speak for IL, since as a Chicagoan we don't know much about what goes on out there in the prairie; except that's where are food comes from.
Shut-off on the hot water side of a tank is a standard code violation write up here in the City. I can tell you that it is common for city inspectors to view any shut-off within reach of the tank as being part of that. Shut-offs further down the line, not within reach of the tank, are generally left alone.

Thanks, Marcus. It may simply be to prevent inadvertent mistakes, thinking the supply to the tank is off when it may not be.

Here's an example from a month ago. We were wondering why the added cold supply pipe is tapped into the drain valve. I said " He could have just put a tee here" at the valve on top of the tank. "Hey, that's the hot side". The cold water shutoff is on the loop that comes down from the top, pic2.

Yes, I got the electrical item, needs flex conduit.

Originally Posted by Garry Sorrells

They make the assumption all think in the same manor. Shut off next to tank.
But is it stated anywhere the distance to valve as a min or max distance?

If you have a HW tank in a bathroom and the distance to the fixture shutoff valve is 18 inches, is it then in violation to the code in IL.

Illinois code states the shut off valve is to be within 5' of the tank.

TITLE 77: PUBLIC HEALTH
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SUBCHAPTER r: WATER AND SEWAGE
PART 890 ILLINOIS PLUMBING CODE
SECTION 890.1190 WATER SUPPLY CONTROL VALVES AND METER

Section 890.1190 Water Supply Control Valves and Meter

d) Water Heating Equipment. A shut-off valve shall be provided in the cold water branch line within 5 feet of each water storage tank or each water heater.

Its the Chicago code that specifys there shall be a shut off valve installed on the inlet side only.

18-29-503.1.1 Shut-off valves Shutoff valves for water heaters or heated water storage tanks may be installed on the inlet side only.

Most towns and cities I do plumbing in will write you up for installing a shut off on the hot side of the water heater or hot water storage tank.

Originally Posted by tom daley

Ron,
Thank you for the two examples. Nightmare.
Combustion Safety's comment on the investigation in Okla. was a bit fuzzy: what precisely do they mean by:
Item 2. Testing safety operating limits.
Item 3. Verifying proper equipment lights off.

I think i know what they mean but i'm not sure.

To be honest I am not sure what they mean.

They included heater water tanks, which means indirect tanks. If there was a 'tankless' WH with the new min booster tank, it could not have one either.

Still nothing to explain it. Would need to see what comic books they had been reading through.

My question for Chicago is on what evidence or theory is this based upon? I mean, this had to go through three public hearings before being voted on into law so somebody had to make the case that the existing plumbing code was insufficient and this was needed for public safety. Also, have these same people attempted to introduce this change into the IPC?

I think you meant to say they allowed a shutoff on the inlet only Ron. ;-)

Hey, I'm all ears on this issue but I need to be sold on it.

Originally Posted by Bob Harper

They included heater water tanks, which means indirect tanks. If there was a 'tankless' WH with the new min booster tank, it could not have one either.

Neither the tank nor the tankless heater could have a valve.

Still nothing to explain it. Would need to see what comic books they had been reading through.

My question for Chicago is on what evidence or theory is this based upon? I mean, this had to go through three public hearings before being voted on into law so somebody had to make the case that the existing plumbing code was insufficient and this was needed for public safety. Also, have these same people attempted to introduce this change into the IPC?