hot water heater

[ikes1234]

when I turn the switch on to light my hot water heater it lights up but when the water gets hot it wont shut off finalie the preasure relief valve blows I let it cool down and lite it again and it does the same thing.any answers ?

[000]

Just an update.
I installed the new thermostat and tested. The heater fired for about 40min then cut out!
I drained out some water and it cut right back in!
Thanks for the help,

[tony_lee]

ikes1234 is the MH new to you and is this the first time you have fired up the heater. Just that to have two independent thermostats fail dangerous at the same time is unusual and I wonder if a previous owner has done some rewiring.

Another alternative is that the safety valve has gone faulty and is blowing off well below the temperature at which the thermostat would cut out. Is it going off with noise and blast of water or just quietly opening and letting water flow.

If you have an electric option, have you tried it on electric to see if the valve still blows off.

[phays]

You may have two problems. The ECO should shut the water heater down at about 180F. Apparently yours isn't doing this. I would first look to make sure both the thermostat and ECO are in good contact with the tank. Make sure the springs are in place to help force the sensors against the tank. Normally, the thermostat will fail to open the circuit and then the ECO will shut the system down. If the ECO shuts it down, the WH won't relight until you cycle the switch.

I don't know if a bad control board could cause this problem, but you could light the water heater and then pull one of the thermostat wires, the WH should shut down. If it doesn't then your problem lies elsewhere and I would suspect the control board.

You can test the sensors by placing them in hot water and using an ohm meter check to see what temperature the contacts open but given the work involved I would just replace them. You have to take them out to test them and the cost for new sensors isn't that high.

[000]

I got the new kit this morning. I will install it this afternoon. If i find it seems like the heater is still not cutting out. What would be the max you would let it run for?
Im going to monitor the water temperature with a thermometer.

[Doug_and_Cassi_]

I agree it's most likely thermostat. To re-state a VERY DANGEROUS situation, if your pressure relief valve is going off you need to repair ASAP. If that pressure relief valve fails and heater keeps going (it will if thermostat is bad) that 6 r 10 gallon water heater turns into a bomb.

I saw a training film put out by a major fire department or building code department. A 40 gallon water heater blew and completely destroyed (leveled) a small house. Not a situation to be taken lightly.

[000]

Sorry to bring this back up to the top but..

How long was the water heater on before the prv blew off?
Also when you installed the new t stat did it work fine?
I'm having the same issue.


Thanks

[Old-Biscuit]

ikes1234 wrote:
thank you for your help I have a attwood model G6a-6E how do I find out how to installthem and where can I buy them?

New ECO & T-stat come as a set with insulating cover.
Purchase as most any RV Supply Store or via on-line. About $14


Open outside compartment. they are located under the black spongy cover with ECO & T-stat label.
ECO on left & t-stat on right. Three bend over tabs hold t-stats against tank wall with spring pressure and plastic washer.
Disconnect wires (note location/mark them) peel label off, bend tabs up/out...pull old t-stat. Place new against tank, compress spring/plastic washer....bend tabs over/in tight against outside lip of plastic washer.
Install new spongy cover/label....reconnect wires.

Here is a manual.......pg. 16 description pg. 24 middle diagram is wiring schematic for your model.

Atwood Service Manual

Also read up on 'air pocket' and weeping relief valve.

[ikes1234]

thank you for your help I have a attwood model G6a-6E how do I find out how to installthem and where can I buy them?

[Old-Biscuit]

IF it is continuing to heat water until pressure relief valve lifts you are just shy of having a steam bomb.

There are two t-stats.........normal (140*F) and a high temp (180*F)
BOTH of those have to be bad for heating of water to lift PRV (210*F/150 psi)

Continuing to use is flirting with danger.
Get a new set of t-stats ASAP and make sure they are tight against tank when you install.

What brand (Suburban----Atwood) and which model)???

[nelson]

High limit on the thermostat is not working change it now. It's an easy fix.

[mph_medic]

Watch this one ... I even learned something one this one..

CLICK HERE

[OnaQuest]

You might try to reestablish the air head before you replace the thermostat. However, I agree that it certainly sounds like it is defective.

[lotsofexperienc]

I will third the thermostat. They are relativily easy to change. The kit will come with a new t-stat and an ECO ( emergency cut off )

[Dale_Traveling]

I'll second the bad thermostat. There are You-Tube videos on how to troubleshoot but you will need to know manufacture and model.