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nporst · 08-28-2021, 05:24 PM

2005 Bounder w/ Atwood GC10A-43 10 gal. gas / electric water heater. Normal temperature is 140 degrees. Only getting about 110 degrees.
Four years ago circuit board, thermostat, and thermal cut off were replaced. All mixing faucets (ie: outdoor shower) have been checked. First thought is to replace the thermostat, which I have on board. Don't think I have an issue for the circuit board to be bad and I think the cut off is either good or bad. We are on the road in the middle of an eight week trip. Debating whether to swap thermostat now or wait until we get home. Any thoughts? Thanks for a great forum.

MrMark52 · 08-28-2021, 08:48 PM

The ONLY thing that controls temperature on the water heater is the thermostat.

Are you certain the coach doesn’t have a hot water balancing valve on the hot water line? This type of valve is used to extend your hot water by mixing cold water with the ho water. They are typically adjustable to control the water temperature being fed to the coach (140 degrees will scale human tissue, but that temperature is needed to kill the bad nasties that can live inside the water heater tank.

Cat · 08-28-2021, 09:17 PM

If you have winterizing valves they can cause problems with temperature. Many Atwood GC models have a mixing valve on the back of the tank. They use this to get more hot water from a smaller tank. They heat the water higher than normal water heater Temps then they mix it with regular cold water to get 140 120 water Temps. Good in theory but they get calcification in the valve this causes no hot water from the taps but the water heater its self is working properly. The valve if you have one can be cleaned out.
Check your model parts list on line to see if you do have one.
You also could catch some water from the hot water expansion valve and check the water temp that way. If its the correct temp then its either mixing valve or winterizing valve or thermostat depending on what you find the temperature is. Safe travels---- let us know what you find is the problem. Don't ask then disappear.

Old-Biscuit · 08-28-2021, 10:06 PM

Your Atwood GC10A-4E is standard model....No Mixing Valve
*Atwood GE9-EXT/GE16-EXT are Mixing Valve Models (use a 155*F t-stat ....mixing valve out is 130*F)

Thermal Cut Out works or is blown.....190*F
**Water heater working so thermal cut out is good

T-stat Opens at 140*F/Closes for reheat cycle at 110*F

T-stats rarely fail 'low' temp...they fail CLOSED and cause overheating or fail OPEN and don't allow heating to occur

T-stats need to be held tight to WH Tank wall...if not higher then normal temps can occur due to loose fitting

Low water temps are more then likely due to BYPASS valve being cracked open causing Cold water to Mix with the HOT out and diluting he temp

Luke warm temps can also occur if shower(s) are turned off via the button/lever on shower hand vs closing the knobs
If Cold/Hot knobs are open the faucet acts like a mixing chamber and Cold dilutes the Hot temp

Check the WH Tank BYPASS valve
Check the Shower (especially outside one) knobs are closed

If both are closed/no flow THEN issue could be the T-stat
But sounds more like cold/hot mixing going on

bddadles · 08-29-2021, 10:21 AM

I don't have an Atwood but I flush my tank 3 - 4 times a year. You would be surprised at the amount of crud you get. Be sure to hit the element to remove calcium build up.

nporst · 08-29-2021, 10:58 AM

Following the comments, I have checked by-pass valves, outside faucets, inside shower. All are in proper positions. I'm still leaning towards the thermostat. I thought maybe it might be loose but Old Biscuit noted that would cause higher temps not lower. Our next stop is Cannon Beach, OR, I will probably change thermostat then. With 110 degree water temp this is an inconvenience, not a fix now issue. Have to decide if I wait four weeks until back home, Escondido, CA. Thanks for input and support.

Old-Biscuit · 08-29-2021, 11:28 AM

Right after a heating cycle CAREFULLY take a sample of water via the T&P Relief Valve
Gloves/container....Slowly lift T&P Lever CAUTION: HOT water

Then measure temp with a thermometer.
That will tell IF heating cycles are reaching full temp (140*F )
If temp is at set point then T-stat is working......then issue is cold mixing with hot

MrMark52 · 08-29-2021, 12:19 PM

I’m with everything Old Biscuit is telling you! He’s giving good direction/instruction.

nporst · 08-29-2021, 04:32 PM

Water temperature at kitchen faucet and T and P valve same, 110 degrees. Thermostat? Thanks

Old-Biscuit · 08-29-2021, 04:51 PM

Quote:

Originally Posted by nporst

Water temperature at kitchen faucet and T and P valve same, 110 degrees. Thermostat? Thanks

Water temp AT T&P 110*F

Then T-stat
Make sure to clean tank wall before installing that new one
Insure it is tight against tank wall and that the spade connectors are clean/tight on the terminals

Temp at T&P is KEY to what is going on
PROVIDED same temp is low on electric and propane
Both use same t-stat But different circuits on circuit board

Were the 110*F on Electric and on propane or just One of those heat sources????

nporst · 08-29-2021, 05:04 PM

WH was on electric, I will repeat test on propane.

nporst · 09-01-2021, 04:23 PM

Same results on gas and electric. Disconnected and reconnected all the wires. Temperature now up to 116 degrees. This will be acceptable for the remainder of our trip. Pretty sure its the thermostat but I'll wait to do the replacement in the comfort of my driveway. Don't want to invoke Murphy's Law. Thanks again for all the input and guidance.

MrMark52 · 09-01-2021, 04:30 PM

RE: Old-Bisquit’s comment to make sure contact between the thermostat and the hot water tank - if the thermostat was somehow insulated from the tank, it would cause the water in the tank to be hotter, not colder.

I won’t disagree the stat may be bad. I would also look at the numbers and look up the stat to make sure of it’s rating assuming the rating isn’t actually indicated on the stat.

And just to be sure - you are measuring the water temperature right out of the T&P at the water heater, right?

Old-Biscuit · 09-01-2021, 07:57 PM

Quote:

Originally Posted by MrMark52

RE: Old-Bisquit’s comment to make sure contact between the thermostat and the hot water tank - if the thermostat was somehow insulated from the tank, it would cause the water in the tank to be hotter, not colder.

I won’t disagree the stat may be bad. I would also look at the numbers and look up the stat to make sure of it’s rating assuming the rating isn’t actually indicated on the stat.

And just to be sure - you are measuring the water temperature right out of the T&P at the water heater, right?

Atwood standard t-stat is 140*F
Atwood has an optional 130*F
Atwood HAD an optional 120*F but haven't been in production for decade at least
*Many times the optional 130*F T-stat is advertised as 120*F but not true (amazon Listings)
Atwood has an 'adjustable' t-stat 110*F-150*F (hard to miss as it is big/bulky and in a frame)

Atwood also has a 155*F t-stat that is used only on the XT models (mixing valve versions)

All versions use a 180*F ECO (Energy Cut Off...High temp t-stat)

Changing out t-stat...should do the ECO also
They come as a set with New Foam Insulation Pad