Community Forums

jsunset · 09-15-2013, 03:54 PM

I have a Atwood Water Heater Model GE16_EXT-SP. In the past I have always drained the water heater if we were leaving for 2 weeks or more. This time we left for 3 months. I drained the heater before we left. Upon returning I refilled the water heater, purged both at the pressure relief valve and faucets inside the RV. After about 3 minutes all water stopped at all the faucets. I have drained the water heater 3 times and each time it starts out good water then all water stops at all faucets that I have opened to purge the hot water system. Yesterday, it starting working all day and during the night. This morning it all worked fine, then about mid-morning all water stopped on the hot water side all faucets. The cold water works fine with good pressure. I have replaced our pressure regulator at the faucet for shore water. I have replaced our whole house filter system. I am at a loss of what could be wrong. I am thinking maybe the mixing valve but not sure. Any ideas what I can do to fix this problem.

**CLIFFTALL** · 09-15-2013, 04:05 PM

I think you may be on to something with the mixing valve theory.

Tony Lee · 09-15-2013, 04:13 PM

Usually a collapsed check valve at the cold water inlet to the heater. Symptoms are normal hot water flow for a few seconds and then almost no flow. Turn off the tap and wait for a while and the same thing happens. Reason is that some water is getting past the check valve and that pressurises the air space (acts like an accumulator) so you get a surge until the airspace expands and then only whatever trickle is getting past the valve.
You would likely get the same symptom is you opened the safety relief valve - surge and then a trickle.

If yours has the inbuilt mixing valve then of course that could be the problem although normally they are designed to fail safe and only allow cold water to pass if something goes wrong
Perhaps the check valve I referred to is supplying both the cold water into the heater and the cold mix water to the tempering valve

**CLIFFTALL** · 09-15-2013, 04:20 PM

My Atwood has a check valve on the hot water out but not on the cold water in.

Hikerdogs · 09-15-2013, 04:25 PM

You could very likely have a check valve on both the inlet and the outlet. The one in our Winnebago Adventurer does. The one on the outlet side prevents cold water from entering the water heater when just the cold is turned on at a faucet. The one on the inlet side prevents hot water from being pushed back into the fresh water tank.

Tony Lee · 09-15-2013, 04:54 PM

Yes, can be both hot and cold check valves although the symptoms will vary.

If on the outlet then flow of hot will (usually) always be a trickle, but will be normal if you open the safety relief valve. If it is the inlet valve that has collapsed then flow will be a gush and then a trickle when either a tap or the safety valve is opened.

jsunset · 09-15-2013, 07:56 PM

Thank all of you for responding to my Atwood water heater problem. I found a bad check valve on the hot water outlet. When replaced, we now have hot water in all faucets. Its tough to get to the back of the heater to replace it but worth doing it myself to save a service call. Thanks again Tony, your a lifesaver.

Mr_D · 09-15-2013, 08:00 PM

Ac cording to the pundits in the magazines you are not supposed to open the pressure relief valve and allow the tank to fill totally with water. You are supposed to have the valve closed. That leaves the air in place to allow for a cushion.

**CLIFFTALL** · 09-16-2013, 02:55 AM

Thanks for the update. Glad you found and fixed it.

Frankwh · 09-20-2013, 10:26 AM

Another thing is if that safety valve on the hot water tank starts dripping don't replace it. Drain the tank and refill it and that will leave an air space in the top of the tank and the safety valve will not leak. Another thing I have that attaches to a hose is a little thing I think I bought at Camping World that you can take out the tank drain plug and rinse out the inside of the tank with.

rasum · 09-20-2013, 02:00 PM

I may as well share an experience I had one spring. I was getting ready to go camping. I hooked up the water and I proceeded to flush the winter antifreeze out. It started out fine and then I barely got a dribble out of each tap, hot or cold. I finally remembered that the previous fall I had put a water bottle in the water filter container so I would not waste antifreeze. The water bottle would float to the top of the container for the water filter and it actually plugged the water outlet from the filter. It was one of my dumb ideas. BTW, I had previously tried the plate and O ring so antifreeze would not go into the filter container. But, it leaked so I gave up on that.