Water Heater Relief Valve leaking ?

[G McCall]

A friends RV water heater was leaking water from the pressure relief valve.
He is away from his RV now, but would opening and closing the valve most likely solve his problem ? There may have been air in the lines.

[BB_TX]

I have not tried it on an RV, but have done it on a home water heater as a temporary fix. Opened/closed it several times and it stopped leaking. But replaced it shortly after.

[SlickWillie]

Dang! Exact problem I have, only ours only leaks when on propane, never on electric. I had the dealer check it out this summer. (checks out fine) I knew it would leak again as soon as I ran it on gas. We were out boiling crabs last evening, and DW asks what the water is leaking from the other side of the RV. I pulled the cover, and the burner is on, and the valve is dribbling. As soon as the burner cuts off, the valve stops leaking. Either the heater is over heating, or the valve is bad. I intend to talk to Surburban directly this time. No dealer. I think the valve is less than $20, so no big deal if they don't want to replace it. Oh, and BTW, the blue crabs are great!

[skypilot]

Will - sounds like the valves tension has lessened from age -- My standard practice was to open mine up when draining the water heater and then leaving it 'sprung' all winter (let air circulate I thought to keep it dry in there); dealer says 'NO!!', doing so causes the spring to loose its tension and then it will leak. Sure nuff - happened last year and had to get mine replaced.

[illapah]

Did I read somewhere that when closing the valve to let it 'snap' closed rather that easy release to help prevent leaks?

[Broome101]

pressure has built up from heat of the propane being used, yes either relief the value or tune some hot water on inside will stop it.

[SlickWillie]

quote:Originally posted by Broome101

pressure has built up from heat of the propane being used, yes either relief the value or tune some hot water on inside will stop it.

I really think the valve on my heater is bad. No way it is getting to 150 PSI (pressure relief setting). It does get very hot,but I don't think it is over 210* which is the temperature relief point. Probably just weak from the factory. Funny thing, I've never had one go bad in the stick house.

[Tiffensdad]

Hi all, I have dealt with RV and Home water heaters for a long time and over the years I have seen numerous attempts to "resolve" a leak (i.e. plugging the hole) that have resulted in some disasterous situations.
TPRVs (temperature pressure relief valves) are a mechanical safety device. Understand that it can be dangerous to mess with a relief valve. You can be scalded or create a very dangerous situation, possibly resulting in death.

Typically they leak for a few reasons:
1. The valve is old and it starts to leak. In our RV's these valves typically sit dormant, unused for great lenghts of time which is bad for the TPRV. A couple of times a year, or at least yearly the handle should be lifted, with the water system pressurized and with COLD water in the tank. This will help clear any built up crud. Do not do this excessively though as it will over time contribute to weaking of the spring mechinism.
2. The water is too hot. water heater relief valves will blow at 210 degrees (typical). Most of the time the relief valve will blow before that temperature because of the extra pressure caused by the water expanding. Many of us (I am one) try to keep the temp of the water heater high and mix cold at the point of use to maximize the time you have warm water for your shower etc. When the temp is set high on the heater you approach the limit of the valve rapidly and minor variances in the system can set it over the edge.
3. The pressure is too high relief valves are set at 150 psi. This seldom seems to be a problem in an RV UNTIL the TPRV weakens. Then the pressure that the TPRV releases reduces. Heating the water increases the pressure in the tank and if the valve is weak, or the water overheated....leak...
4. Thermo expansion - probably the most common cause. Water expands as it is heated, the hotter it is the more it expands. Because of the check valves, backflow preventer etc we all have in our RV's it creates a closed water systems hence the pressure as it builds needs to go somewhere.

I have been lucky with all the rigs I have had. I only had to deal with this once on my equipment. I just replaced the valve which was at that time 5+ years old.

Suburban has a Q&A section on their website which gives alot of information on the entire system for those who are interested.

http://www.rvcomfort.com/suburban/se..._questions.php

Hope this helps, be careful out there. See you when we finally get on the road...126 days and counting.

[Fordzilla]

Great link Jerry, We were lucky enough to sit thru a demonstration at last year's Fall rally when they discussed the exact fix. Turn off the city water, then open a hot water faucet in the camper and open the relief valve for a few seconds. This allows an air pocket to form inside the tank of the water heater to allow for expansion. Mine was weeping all the time we were there at the Rally until I got back after listening to the speaker tell us what to do. Now I share it with others who are weeping and thinking of replacing the relief valve themselves. If you ever have a chance to see a cutaway hot water heater you will see there are voids built into the top of the tank.

[HamRad]

Fordzilla,

Thanks for the info. Always good to know this sort of thing.

HamRad