HWH Pressure Relief burped

[davelinde]

Yesterday I was outside and suddenly some water ran out of the grill on the HWH. I investigated and found that the HWH pressure relief valve was dripping. There is a nice little diverter that stops it from dripping onto wires and it was wet. When the diverter got full it dripped to the bottom of the HWH panel (outside FW). When that got full it ran out of the front grill all at once.

When I opened it the valve was still dripping. I dried it all up. Now, a day later it's still all dry. Seems the valve just burped at me once. Maybe it was doing its job? Is this "normal".

 

[SmokeyBare]

Davelinde,

I've found when the water heater has been full of water and the power turned on... or the gas turned on to heat the water... the expansion of the heated water pushes out some of the water through the relief valve. It seems to only happen when the tank is full and is being heated. Once it's up and running... the leaking pressure valve stops dripping.

Only other time it MAY happen is if the water pressure is pretty high and there is a water hammer... somewhere there is a strong flow of water that is suddenly shut off. This could be anywhere in the connected water system... not only in the RV. I believe the water tank is designed to allow a small bubble of air in the very top of the tank... which mostly takes care of this Hammer affect.

Hope this helps.

Marv

 

[jnbhobe]

Well said Marv!! HWT's do spit some water from time to time. JON

 

[davelinde]

Davelinde,

I've found ... It seems to only happen when the tank is full and is being heated. Once it's up and running... the leaking pressure valve stops dripping.

So... this could be normal. No matter actually - unless it starts dripping again I'll consider it OK for now. I hate plumbing repairs.

This response got me to thinking of a theory... We are full time so the HWH has been running non-stop for almost 4 months now. But, last week was our first bout of cold weather and the water from the hose was really, really cold. I'm wondering if filling the HWH with very cold water (as the hot was used) might have caused any unusual expansion later. Dunno. Glad it's not a sign of an impending gusher.

 

[SmokeyBare]

Normal in my opinion... I've seen it on my BigHorn... and it's always stopped after the tank got up to temp... Your right... soon enough you'll know for sure.

Been reading way too many "Leak" posts huh... LOL....

 

[jmgratz]

If you are talking about the valve at the top of the water heater, it is designed to allow excessive pressure to release. So as long as the valve only does it from time to time it is normal. If you have excessive water release or it will not completely close, or you think it is weeping due to constant excessive pressure then I would get it checked out by a professional.

 

[davelinde]

fyi. has not done it since - just checked and it's dry as a bone in there. There is a bit of rust on the deflector.... so I guess it's dripped from time to time. For now I'll call it good.

 

[jpmorgan37]

This issue came up several years ago. Here is the information that I got from Suburban on that topic.


Why does water drip from my water heater's pressure and temperature (P&T) relief valve?
Answer:
You may experience water weeping or dripping from your water heater's pressure and temperature (P&T) relief valve when your water heater is operating. Water weeping or dripping does not mean that the P&T valve is defective. As water is heated, it expands. The water system in a recreational vehicle is a closed system and does not allow for the expansion of heated water. When the pressure of the water system exceeds the relieving point of the P&T valve, the valve will relieve the excess pressure.

One way to reduce the frequency of this occurrence is to maintain an air pocket at the top of the water heater tank. This air pocket will form in the tank by design - however, it will be reduced over time by the everyday use of your water heater. To replenish this air pocket:

Turn off the water heater.

Turn off the cold water supply line.

Open a faucet in the RV.

Pull out the handle of the pressure relief (P&T) valve and allow water to flow from the valve until it stops.

Release the handle on the P&T valve - it should snap closed.

Close the faucet and turn on the cold water supply. As the tank fills, the air pocket will develop. Repeat this procedure as often as needed to reduce the frequency of the weeping P&T valve. If the weeping persists after following this procedure, you may elect to have your dealer install an expansion or accumulator tank in the cold water line between the tank and check valve to relieve the pressure caused by thermal expansion.

Hope this helps,

John

 

[davelinde]

...information ...from Suburban

...to reduce the frequency of this occurrence is to maintain an air pocket at the top of the water heater tank. This air pocket will form in the tank by design - however, it will be reduced over time by the everyday use of your water heater....

Makes a lot of sense. THANKS!