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Topic: Atwood Water Heater - Pressure Relief Valve Replacement Question (Read 219 times) previous topic - next topic
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Atwood Water Heater - Pressure Relief Valve Replacement Question
Our pressure relief valve drips more than it should and so I'd like to replace it.  However, the old valve is very stubborn and I haven't been able to break it free.  I don't want to damage the threaded fitting in the water heater or the water tank.  So is the solution just more strength and a bigger wrench?   Once I'm able to remove the old valve, should I use a bit of plumber's tape (PTFE) on the new valve or is there other material I should use to help seal the fitting?

Thanks in advance.
Re: Atwood Water Heater - Pressure Relief Valve Replacement Question
Reply #1 –
Have you re-established the water heater's air gap recently?
If not , do so before replacing the relief valve, to make sure the valve is the cause.
As the water heats and expands, the air gap allows for the increased in water volume.

The air is gradually absorbed into the water and the gap decreases until there is no air gap.
When the water heats and expands, it has no place left to expand into, leaving only the relief valve, which then seeps.

Getting it out is hard on some heaters, but they do come out.
Never heard of anyone tearing the threads out of the tank while doing this.
Do use teflon tape or paste when installing the new one and it doesn't need to be as tight as possible.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Atwood Water Heater - Pressure Relief Valve Replacement Question
Reply #2 –
Hello Larry.  How often do you re-establish the air gap?  Is this something you do every couple of days?  I've been following this step only if the water heater was cold and then we used the water heater.  I thought once I had an air gap, it was good for a considerable period of time.   Look forward to hearing from you.
Re: Atwood Water Heater - Pressure Relief Valve Replacement Question
Reply #3 –
Not Larry, but you need to establish the air gap every time you empty the water heater.  I had a problem with the relief valve dribbling (worse than a drip - but not as bad as drooling).  The owners manual states that this may happen from time to time due to sediment.  Normally establishing the air gap with clean it out.  For me it did not.  
I opened the valve for a second while it was under pressure from shore water then let it snap close.  I did this a couple times to purge the valve. The dripping stopped.   You DON'T want to do this when the water is hot as it would be very easy to burn yourself.
Currently: 2008 36' Tiffin Open Road
Previously: 2007 Mid Bath
Re: Atwood Water Heater - Pressure Relief Valve Replacement Question
Reply #4 –
As to replacing it, I had mine replaced last winter.  I tried to turn it but could not budge it. 

That's ok, my muscles are not what they used to be.  I contacted a local service guy who came out.  He had a socket that fit over the valve and a breaker bar about 18" long.  He looked like he pumped iron. 

He strained at it - twice - before it began to turn.  He said that is pretty common.  Apparently lime forms in the tiniest gaps in the threads and acts just like Locktite Red, preventing the valve from turning. 

He told me the sockets are easily available on line, but I am carrying enough tools.  If you really want to pull the valve yourself, order the socket.  If the valve is really on there hard, that is the only way you will get it off.

Ken F in OR
'08 MB
Re: Atwood Water Heater - Pressure Relief Valve Replacement Question
Reply #6 –
I finally got around to replacing that pesky pressure relief valve for the hot water heater.  After I found a very large wrench (long handle), it broke loose straight away.  So if your PRV seems to need replacement, the secret is to use the biggest wrench you can find!   As always, the right tool often makes the job easier.  I wonder how often I have forgotten that rule in my life ... may a 100 times!