Water Heater Pressure Valve Leak

Topic: Water Heater Pressure Valve Leak (Read 845 times) previous topic - next topic

Water Heater Pressure Valve Leak

February 01, 2020, 06:18:23 pm

This one is for us water heater Foretravelers. I posted awhile back that I was getting a little seepage from the water heater pressure relief valve. It turns out that this is a common issue, however, I had not run into it before with other rigs. Anyhow, the water heater is designed to maintain an air bubble on top and when this bubble is gone you get seepage through this valve (I replaced this one twice before I came across this information). There is a procedure to reestablish the bubble but it doesn't work for me.

So... following in the steps of the estimable Barry and Cindy, I gave up on the fix and did a workaround. Now, when there's seepage it falls harmlessly to the ground rather than into my water pump compartment. More than one way...
jor

Re: Water Heater Pressure Valve Leak

Reply #1 – February 01, 2020, 06:58:15 pm

Quote from: jor – February 01, 2020, 06:18:23 pm

This one is for us water heater Foretravelers. I posted awhile back that I was getting a little seepage from the water heater pressure relief valve. It turns out that this is a common issue, however, I had not run into it before with other rigs. Anyhow, the water heater is designed to maintain an air bubble on top and when this bubble is gone you get seepage through this valve (I replaced this one twice before I came across this information). There is a procedure to reestablish the bubble but it doesn't work for me.

So... following in the steps of the estimable Barry and Cindy, I gave up on the fix and did a workaround. Now, when there's seepage it falls harmlessly to the ground rather than into my water pump compartment. More than one way...
jor

That valve is failing. It opens in two ways, rise in temperature and rise in pressure. The gasket material on the valve seat is at the end of its service life.
I have one of those surplus to my needs in the 3/4" pipe thread, yours for your address. Mine is 1/2" so I used this 3/4" one until the man in the UPS truck delivered my new valve.

Re: Water Heater Pressure Valve Leak

Reply #2 – February 01, 2020, 06:58:48 pm

RE-establish the air gap.

Turn off pressure water and bleed off PSI at any faucet.

Remove the drain plug (have a new Atwood nylon drain plug on hand (ya about $1.50).

If you have kept your water heater drained of mineral once a year, all you need to do is drain 1 gallon and put in the new plug.

Turn the water pump back on. That should fix it.

If you have not drained the minerals within the last year:
Buy 5' of cheap thin wall clear plastic hose (any hardware store)-- diameter that will fit reasonably within the drain plug opening (sorry don't recall the size but 1/2" ID sticks in my mind).
Do as above and insert the hose.
Start a siphon and move the water heater end around in the bottom of the water heater (drain is NOT in the bottom).

When you stop seeing minerals in the clear hose, stop. If the water heater runs out of water and mineral are still present, turn on the water pump and refill tank. REPEAT until no more minerals.

Re: Water Heater Pressure Valve Leak

Reply #3 – February 01, 2020, 07:03:51 pm

1/2 inch is the size on mine.

Re: Water Heater Pressure Valve Leak

Reply #4 – February 01, 2020, 07:30:13 pm

Quote from: Realmccoy – February 01, 2020, 07:03:51 pm

1/2 inch is the size on mine.

Same here. I replaced mine 4 years ago with the one linked below. Has never leaked a drop.

0121325 - Watts 0121325 - 1/2" LF1XL-4 T&P Relief Valve, Lead Free (150 psi)

Hott Rod Installation, Atwood GH6-7E

Re: Water Heater Pressure Valve Leak

Reply #5 – February 01, 2020, 07:32:41 pm

Jor
Nice work on the drain, but............... I'm not sure you would want to restrict the pop-off relief valve that much. When they release due to overtemp they release a lot of steaming water quite rapidly. The valve shouldn't be dripping if working properly.

Also I have never worried with a "bubble" in the hot water tank, probably because I have always used a accumulator or bladder tank on the fresh water pump system. Without one you would need an air pocket in the hot water tank to keep from overpressure due to heating the water.

If routing the pop off valve below the coach, I would stay with the 1/2" pipe size, just my opinion and your mileage may vary.........

Re: Water Heater Pressure Valve Leak

Reply #6 – February 01, 2020, 08:02:11 pm

Many times this happens when first starting the water heater and the water is cold. If you have the coach unhooked from city water and pump off open any hot faucet and the expanding water will come out the faucet instead of the pressure relief valve. Once the water is hot close the faucet and use as normal and should not have a problem.

Re: Water Heater Pressure Valve Leak

Reply #7 – February 01, 2020, 08:26:37 pm

I forgot to explain that when the gasket material ages out it gets thinner, and the thermometer that pushes the valve open opens at lower and lower temperatures.

Re: Water Heater Pressure Valve Leak

Reply #8 – February 01, 2020, 10:35:36 pm

Hey, great responses. Let's see...

Valve Failing: I don't think this is the issue. I have installed two new valves both of which did the same thing.
Clean Sediment: I give trhe tank a thorough wash 2X per year.
Reestablish Air Pocket: That is the procedure I have tried several times. Works for awhile, then...
Too Small Drain Hose: Hmmmm... I'll have to consider this. It's a 1/2" to a hose barb. The plastic hose is just pushed onto the barb. My idea is that if the thing blows it will just blow the hose off. Initially, I was going to use a larger hose but I wanted to avoid another floor penetration.
Accumulator: Good point. I removed the accumulator on this rig but I think it was doing it before. Can't remember (first the hair then the memory).
Open Faucet: Wouldn't this waste a lot of water or maybe I am not understanding this post.

Maybe I should go back to one with Aqua Hot!

Anyhow, thanks to all. Food for thought.
jor

Re: Water Heater Pressure Valve Leak

Reply #9 – February 01, 2020, 10:48:16 pm

The TPRV (valve) drain pipe must be the same size as the valve thread which is in most cases 3/4". The valve is designed to release at approximately 180 degrees which will have built a huge amount of pressure in the tank, restricting the valve with a smaller diameter pipe can be dangerous.
If the pressure in the tank is normal and the valve is dripping a slight tap with a hammer to the "pin" will often seat it.

Re: Water Heater Pressure Valve Leak

Reply #10 – February 02, 2020, 07:01:25 am

jor,

Just a few thoughts to try to fix your problem.
Does this T&P leak all the time? (like even when the heater is off)
If it only leaks when heating water maybe it is doing its job.
You could have a failing snap/bimetal thermostat. Even new I have seen them not open at the correct temp.
Could be the wrong temp thermostat, as it looks like you have a non adjustable one.
Does the T&P valve temp setting and the temp setting of the thermostat have enough span between the 2?
How have you determined that the air expansion bubble in the tank has vanished? Just because the T&P valve is leaking doesn't mean that your expansion bubble has vanished.

Mike

Re: Water Heater Pressure Valve Leak

Reply #11 – February 02, 2020, 09:30:32 am

Lots of action on this one. You'd think it was about tire pressures or black tank maintenance!

Does this T&P leak all the time? (like even when the heater is off)
Never when the heater is off. Sometimes when it is running. We are not talking about much water. Maybe a tablespoon in several hours and not on every cycle. I don't want any water in any compartment!
If it only leaks when heating water maybe it is doing its job.
That's what my research indicates. Like I said above, this is a common issue but one that I had not encountered before this coach.
You could have a failing snap/bimetal thermostat. Even new I have seen them not open at the correct temp.
Could be the wrong temp thermostat, as it looks like you have a non adjustable one.
Does the T&P valve temp setting and the temp setting of the thermostat have enough span between the 2?
Not adjustable on this unit. Hot water temp is correct.
How have you determined that the air expansion bubble in the tank has vanished? Just because the T&P valve is leaking doesn't mean that your expansion bubble has vanished.
Just from reading numerous threads addressing this issue. I think after three valves have done the same thing I can rule out the valve itself.

Re cleaning. When I bought this rig it had not been well maintained except for the haftado stuff. The hot water smelled like rotten eggs and there was lots of debris in the tank. After several cleanings no more debris.

Re the danger issue, I'm not worried as it's just a plastic fitting and a push on hose. (famous last words)

OTM, thanks for your generous offer.
jor

Re: Water Heater Pressure Valve Leak

Reply #12 – February 02, 2020, 10:06:53 am

Quote from: jor – February 02, 2020, 09:30:32 am

Lots of action on this one. You'd think it was about tire pressures or black tank maintenance!

OTM, thanks for your generous offer.
jor

You're welcome, although my generosity revolved more around my not wanting to throw this slightly used valve away.
Without your accumulator, yeah the T&P valve will need to vent. BTDT this rig has an Extrol style tank. FWIW if you're running on internal water, turn off the pump and open hot water faucet and that trickle of water is the expanded water from the hot water heater.

And yes on my water heater the Klixon switches were toast. I only have about 2 hours each day to do anything beyond the normal routine of life. So all of my usable time has been spent getting my Toad ready for the road. The hotwater heater I had been running using a kitchen timer and the on-off switch. It now has a new 1/2" pipe T&P relief valve and new Dometic/Atwood Klixon switches.

Art

PS, All that is left on the Toad are the turn signals. Then I have a new valve mechanism for my Aqua Magic Galaxy/Starlight toilet. Free Beer?

Re: Water Heater Pressure Valve Leak

Reply #13 – February 07, 2020, 06:24:55 pm

Update

I decided to take a few more steps on this thing to see if I can cure this pesky problem. I checked the temp of my hot water again and was surprised to note that it was about 154 degrees. To cure that issue I just installed an Atwood adjustable thermostat. Initially I set it for 120 degrees and so far so good.

Tomorrow I'm going to clean it again.

I also bought an accumulator and will install it next week.

Also checked the air gap on my electrode and noted it was about 1/16" too wide.

Forward we go. Or as Dwayne at The Slabs would say, "Onword thru the fog."
jor

Re: Water Heater Pressure Valve Leak

Reply #14 – February 07, 2020, 08:01:52 pm

Quote from: Old Toolmaker – February 02, 2020, 10:06:53 am

PS, All that is left on the Toad are the turn signals. Then I have a new valve mechanism for my Aqua Magic Galaxy/Starlight toilet. Free Beer?

Brand?

Re: Water Heater Pressure Valve Leak

Reply #15 – February 09, 2020, 07:50:45 am

Quote from: jor – February 07, 2020, 06:24:55 pm

Update

I decided to take a few more steps on this thing to see if I can cure this pesky problem. I checked the temp of my hot water again and was surprised to note that it was about 154 degrees. To cure that issue I just installed an Atwood adjustable thermostat. Initially I set it for 120 degrees and so far so good.

Tomorrow I'm going to clean it again.

I also bought an accumulator and will install it next week.

Also checked the air gap on my electrode and noted it was about 1/16" too wide.

Forward we go. Or as Dwayne at The Slabs would say, "Onword thru the fog."
jor

Your thermostat may have been bad given 154 degree water. They are supposed to be set at 140 degrees.

Your setting of 120 degrees is too low as that would allow some forms of bacteria to flourish.

Re: Water Heater Pressure Valve Leak

Reply #16 – February 09, 2020, 09:19:05 am

Quote from: Moby – February 07, 2020, 08:01:52 pm

Brand?

1968 Siata Spring

Re: Water Heater Pressure Valve Leak

Reply #17 – February 09, 2020, 10:33:44 am

Quote from: Old Toolmaker – February 09, 2020, 09:19:05 am

1968 Siata Spring

Quote from: Old Toolmaker – February 09, 2020, 09:19:05 am

1968 Siata Spring

No, no, no.
Referring to the free beer

Re: Water Heater Pressure Valve Leak

Reply #18 – February 09, 2020, 10:38:39 am

Quote from: Old Toolmaker - An hour ago

1968 Siata Spring

Moby:
No, no, no.
Referring to the free beer

Bud Light. Here in the land of practical no-nonsense farmers, micro breweries don't seem to have caught on yet.

Northern Maine? The part that sticks up into Canada? Micro Breweries and the home of New Balance sneakers.

Re: Water Heater Pressure Valve Leak

Reply #19 – February 09, 2020, 02:18:47 pm

Quote from: Old Toolmaker – February 09, 2020, 10:38:39 am

Quote from: Old Toolmaker - An hour ago

1968 Siata Spring

Moby:
No, no, no.
Referring to the free beer

Bud Light. Here in the land of practical no-nonsense farmers, micro breweries don't seem to have caught on yet.

Northern Maine? The part that sticks up into Canada? Micro Breweries and the home of New Balance sneakers.

Stella would have been acceptable.
FWIW, Mother in Law had a Siata.

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