Dear Dave,
How can I tell if my water heater pressure relief valve has gone bad? We go camping for three months at a time and leave the water heater on electric the whole time. I have noticed that some cooler mornings, low 60 degrees, that the water heater drips some water. Not a lot, and I assume that this is due to condensation since it stops when the day warms up.
On our last trip, our water pressure gauge at the city water source went a little wonky and the pressure going into the RV went up to 55 psi. At this pressure the water heater dripped much more water, but when the pressure was dropped back to 40 psi, the drip stopped.
How can I test the water heater valve to make sure it is working. How hard is it to replace, if need be? My RV repair shop wants $325 to install a new valve, which seems very high to me, especially since I am not sure the valve is bad. Thank you. —Richard, 2022 Cruiser Twilight
Dear Richard,
It must be water heater week (with several questions about them received from our readers)!
The pressure relief valve is in the upper right corner with the red circular label.
Most are designed to relieve pressure inside the tank at 150 psi or 210 degree F. Water heater manufacturers recommend to take the unit in to a dealership or service center. There, a certified technician can use the proper tools to diagnose whether it is simply “weeping” due to high pressure or hot temperatures, or is actually leaking and bad.
When the water temperature inside the tank rises, there will be expansion. Since it is a closed system, it will weep or be relieved through the pressure regulator, which is normal operation. The tank should have an air gap at the top that is designed to allow for this expansion. However, the water level can rise higher with repeated use and even due to a buildup of lime and calcium on the bottom.
Water heater pressure relief valve maintenance
It is recommended to periodically open the relief valve ONLY WHEN THE WATER TEMPERATURE IS COOL. Turn off the water heater, turn off the cold water supply, and open a hot and cold water faucet inside the rig. Lift the handle of the relief valve and allow the water to flow out until it stops and shut the valve. Here is the procedure as listed in the Suburban owner’s manual.
So, to properly test the relief valve, you would need to verify the temperature of the water inside the tank, the pressure, and the air gap, which is why Suburban recommends taking it to a certified technician.
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I just bought this RV in December. There have been multiple leaks under the sink in the kitchen and the bathroom. I have had it in for repairs multiple times at the dealership and they say they have fixed it, but I beg to differ. And in the overall grand scheme of things, it doesn’t leak continually. Now under the kitchen sink it only leaks when I turn on the propane portion of my water heater. I have the electric part turned on all the time. … —Julie, 2024 Forest River Flagstaff
Read the rest of Julie’s question and Dave’s answer.
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Dave, you said to open a hot and cold water faucet inside but the procedure for Suburban just says to “open a faucet”. I’m just making sure before I do this procedure.
Gil,
I saw that after I posted? I have always opened both just to make sure there was not pressure just to be safe.
How come the release valve always seems to be installed backwards – meaning the flat side is away from my finger?
If you look at it, it has to open for the valve stem to work. Just keep a piece of 3/8 tubing in the compartment and slide it over the handle.
Excellent idea, Bob. But that just points out the ‘design flaw’ in the first place.
Tommy,
Are you sure your finger is not installed backwards?
You may have something there, Dave. That must have happened one night while I was asleep.
$325 to replace the valve? You can buy a new one at Home Depot or Lowes for around $30 and it’s a five minute job to replace. Chances are you don’t need a new one. Follow Dave’s instructions to get an air space back in the tank.
I had a similar experience this past winter. Usually we stay about a month maximum in one place. This past winter we stayed put about 4 months, after 2 months my wife came running in saying the hot water heater was spewing water out. A nearby camper that is a RV tech did just the same and now every month I do as Dave suggests.
Thank you, Dave! Have a great week and safe travels!
Weeping is common with these valves which leads to some calcium or other buildup on the plunger. Exercise the valve occasionally will help alleviate this. I have cleaned the valve by removing and soaking in white vinegar for an hour or two. It is an inexpensive and easy to replace valve; just screw it in! (Like Tommy below says the flat side is always on the wrong side.) Right on! Apparently no reason for it, it’s just co. policy!