Hot Water Tank overheating

[Fixedblade]

Greetings all: My first post and still a newbie in RV camping. I have a 2000 Minnie Winnie motorhome with an Atwood GH6-8E hot water tank. LPG fired only. It's been working fine and suddenly last weekend I noticed hotwater gushing down the side of the RV from the Pressure Relief Valve. I've tried using it a couple more times and I find that the gas flame won't shut off when it gets up to temp and is overheating the water and causing the pressure relief valve to blow. This is the electronic ignition model. Anyone familiar with this problem and probable fix. Thermostat?? Thanks in advance.

[Fixedblade]

Greetings all: My first post and still a newbie in RV camping. I have a 2000 Minnie Winnie motorhome with an Atwood GH6-8E hot water tank. LPG fired only. It's been working fine and suddenly last weekend I noticed hotwater gushing down the side of the RV from the Pressure Relief Valve. I've tried using it a couple more times and I find that the gas flame won't shut off when it gets up to temp and is overheating the water and causing the pressure relief valve to blow. This is the electronic ignition model. Anyone familiar with this problem and probable fix. Thermostat?? Thanks in advance.

[Route 66]

Fixedblade, welcome to iRV2.

Let us know what the outcome is.

It could very well be the thermostat.

One thing to check is that all the electrical connections are making good contact.

[Frank P. Martin]

While it might be the thermostat, it could also be the relief valve. If enough water is escaping from the relief valve, cold water replacing it in the tank could possibly be keeping the gas on.

Sometimes, water starts escaping from the relief valve because there is no air bubble in the tank. If there is no bubble, the water has no place to expand when it gets hot and its only recourse is out the relief valve. This can be easily rectified by simply draining and refilling the HWT. Since this is a cheap fix attempt, I would try this first. It might be all that's needed.

[Ray,IN]

Hello, and welcome to the irv2.com family! If you are willing, wait until the heater is cool then remove the thermostat cover. Gently move the insulation to expose the thermostat, then make sure it is tight against the heater tank. Sometimes the thermostat will vibrate away from the tank, which naturally makes the thermostat much cooler than actual water temperature. Replace the insulation to cover the thermostat after you insure it is tight against the tank, replace cover, and test it.

[RV Wizard]

Fixedblade, welcome to iRV2.com. We are glad to have you join us here and look forward to reading of your adventures and experiences. I see that you have gotten some good info. Let us know the outcome. Have a great summer and enjoy the website.

[NeilV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ray,IN:
Hello, and welcome to the irv2.com family! If you are willing, wait until the heater is cool then remove the thermostat cover. Gently move the insulation to expose the thermostat, then make sure it is tight against the heater tank. Sometimes the thermostat will vibrate away from the tank, which naturally makes the thermostat much cooler than actual water temperature. Replace the insulation to cover the thermostat after you insure it is tight against the tank, replace cover, and test it. </div></BLOCKQUOTE>

Ditto! It is a thin sheet metal bayonet mount and does come loose.

I was cleaning the shower surround when the water heater on my previous coach acted up like yours and the heat unglued the surround from the wall. If someone was showering it would have been very bad. It went to a steam showen in the blink of an eye.


Don't just press the foam tape down to hold the stat in place. You have to press the ears back down on the metal mounting ring to do it right.

[Fixedblade]

Well, I'm back and covered with hot water....and still have an overheating Atwood. I pulled the anode plug and drained it. Also replaced the anode as it was so caked with minerals it almost wouldn't come out of the hole. I then replaced the 2 little thermostats that lay against the tank with new ones from the local RV dealer. I then went thru the procedure outlined in the ops manual to re-establish the "air bubble" that I understand is important in these little heaters. Actually, I went thru the process 3 times and each one ended with the same pressure release valve letting go and very hot water streaming out. The gas jet is not shutting off and the water gets extremely hot so with the thermostat off the list, what else do I need to check?? I'd like to get this thing fixed so I can GO CAMPING....

[Ray,IN]

My next step would be to replace the thermostat; or, contact Atwood directly.

[Tom N]

I'll mention you should not have an anode rod in your Atwood. The Atwood utilizes an aluminum tank and no anode rod is needed. Atwood does not recommend an anode rod and they do not install them at the factory.

-Tom