Water Heater Pressure Relieve Valve

When ever I turn on my water heater and the water is cold in the tank, I let the faucet on a bit to trickle. The reason for this is that tank is small and when hot water expands I needs a place to go. Once pressure builds up relief valve may start to drip. Better that valve drip then to have a water line burst.

The owners manual on our unit says that a little "seepage" is normal.

I quit worrying about it.

Waking up an old thread here.
I have a Suburban SW6DE water heater (2013). The PRV has leaked since new. I have repeatedly drain to reestablish the air pocket to allow expansion (per the instructions provided in this and other forums) but it still drips when heater reaches temperature. I figured the PRV was bad so I replaced it. It still drips. Some say this is normal, but I have never had this problem in the 6 previous rvs with Suburban heaters I have owned.
Anyone have any ideas why my PRV continues to leak?

liveneasy wrote:
Typical home water heater relief valves are 3/4", while most RV water heaters use a 1/2" valve. The 1/2" valves are generally not available from Lowes, Home Depot or other chain stores, but may be found at plumbing supply stores.

If this is true, (haven't checked mine), why not just install a 3/4 to 1/2 inch reducer and go with the valve that is always readily available????

Something else... Turn off your water and let it cool, If you are hooked to city water and sewer just run water through it to cool.. Now shut off the water and pull the drain plug.. Use the manual lever to open the TPR valve.

Once it's drained, if there is any "Nasty Stuff" flush it When finished replace the drain plug, close the TPR and restore water.. You should be good now.

NOTE that if you are in a park with high pressure you MUST use a regulator or this too can "Pop off" the valve (High pressure, it's full name is Temperature Pressure Relief Valve)

If this does not work, Recall that so far you have spent nothing and go follow the advice of those who told you how to replace it. YES they do wear out. Sometimes.

Moved from Technology Corner

the Pressure / Temperature valve will leak if the unit fires to high. try turning down the t-stat if you have the adjustable type.

If re-establishing the air pocket doesn't work... replacement is quick and easy. Typical home water heater relief valves are 3/4", while most RV water heaters use a 1/2" valve. The 1/2" valves are generally not available from Lowes, Home Depot or other chain stores, but may be found at plumbing supply stores. The last time I had to replace one I ordered it through Amazon for $9.50 plus shipping.

Before you replace it, try to re-establish the air pocket. Without an air pocket they will drip.
1. Turn off the water heater.
2. Turn off the cold water supply line.
3. Open a faucet in the RV.
4. Pull out the handle of the pressure relief (P&T) valve and allow water to flow from the valve until it stops.
5. Release the handle on the P&T valve - it should snap closed.
6. 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.

1L243 wrote:
I have noticed that the pressure relief valve on my water heater is leaking occasionally when hot. Is this a sign of a bad valve or something else?

Are RV water heater valves the same as a house hold water heater.

You should consult with an RV parts dealer. I changed mine out. No problem. You just need a big wrench and some pipe dope.