Water Heater Pressure Release Valve

[joraz]

My water heater pressure relief valve is dribbling again. I replaced it a few months back and then I read that this dribbling is common and results from lack of the requisite air bubble above the water in the tank.



Here's what I am doing to restore the bubble. I heat the tank, turn off the tank, turn off the water pump, turn on a hot water faucet and open the pressure relief valve to release the water.


When I do this I get just a little water out of the valve and no change in the dribbling. What is the proper procedure? Thanks.
jor

[wildtoad]

Let me guess you have a Suburban wh? Mine has done what you describe from day one and I have replaced the valve, done every combination you could think of to keep it from leaking. Frustrating thing is that sometimes it works correctly for one or two cycles then it drips. I personally think Suburban is full of c**p when they say it’s normal. It is most certainly a design failure that they refuse to admit or fix. Anyway I’ve just quit worrying about it.

I don’t see that you are doing it wrong.

[W.J. Demo]

I can’t answer your question; but, good on you for having a water heater. Just don’t understand all the folks that have hot water heaters. I just can’t figure out why they have to heat their hot water 🤪

[Gary RVRoamer]

Just for clarification: The water tank doesn't need to be hot to do establish a proper air head (bubble). And its safer to work with cool water than at 130-160 degrees.

[Skiddy]

there will not be an air bubble if you bleed the air out through the relief valve. am I missing something here, I though you needed the air pocket since water doesn't compress under pressure like air does

[Skip426]

Originally Posted by Skiddy

there will not be an air bubble if you bleed the air out through the relief valve.

X2. To re-establish an air pocket in the top of your water heater . Turn off all water supplies ( shore and coach pump ) open a hot tap somewhere in the coach , and open the tank drain . Drain about a gallon of water and close the drain . With the hot tap still open inside the coach , turn on the supply and bleed out excess air through the tap . The hot out line from the tank is lower than the top of the tank and the relief valve.

Every time you open the relief valve is a chance you'll get some crud on the valve seat causing it to leak.

[twinboat]

Drain the water heater, leave the P/T valve alone and then refill trapping the air up top.

[Old-Biscuit]

Air pocket....
Turn off water heater
Turn off supply water
Open closest faucet to relieve pressure.....leave open
OPEN T&P Relief Valve via lever......hold open until water stops running out
Let T&P Snap close
Close Faucet
Turn on water supply

The above procedure is straight out of service manual.


IF T&P still weeping then calcium/minerals have probably built up on valve seat and it is not completely closing.
Open/snap closing a few times with water supply on can help clear the crud.
CAUTION: If water heated it will be scalding hot/steaming if you mess with T&P

[joraz]

Thanks for the replies. I'll try Skip's recommendation and if unsuccessful, I'll go with Twin. Oldbiscuit, that is exactly what I've been doing without success.

jor

[keymastr]

So the valve is designed to let pressure go past if the water has been heated too hot. Your heater may just be heating too much and the valve is doing it's job. Suggest you test the temp and see if your thermostat is faulty.

[joraz]

Suggest you test the temp and see if your thermostat is faulty.

Didn't think of that. Thanks.
jor

[Old-Biscuit]

Originally Posted by joraz

Suggest you test the temp and see if your thermostat is faulty.

Didn't think of that. Thanks.
jor

Suburban water heaters
T-stat---opens at 130*F
High Temp T-stat...opens at 170*F
T&P Relief Valve------OPENS at 210*F/150 PSI






Tucson AZ........VERY Hard water (which is probably building up on on valve seat)

[joraz]

Suburban water heaters


It's an Atwood. Preset at 140. Re Tucson, this is the first time I've encountered this problem. The three rigs I've had previously had the same heater (10 gallon Atwood). The valve is pretty new and I flush out the tank regularly. I'll try the suggested methods and post back. Thanks.
jor

[wildtoad]

Originally Posted by joraz

Suburban water heaters


It's an Atwood. Preset at 140. Re Tucson, this is the first time I've encountered this problem. The three rigs I've had previously had the same heater (10 gallon Atwood). The valve is pretty new and I flush out the tank regularly. I'll try the suggested methods and post back. Thanks.
jor

I’ve had five motorhomes of various ages. All except this one had Atwood and none of them ever leaked. Oh well.