Atwood water heater GC10A-3E

Most water heaters can operate on either propane or electric. The question is where is the switch to turn on the electric heater. The coach I have now the switch is next to the propane switch. I had a 5th wheel that the switch was located in the outside panel of the water heater. If you do not have a inside 120 water heater switch, I would check the outside panel. The red light comes on ever time the water heater lights on propane.

Make sure the circuit breaker is "on" for the HWH. When plugged in to power it should automatically select electric unless you have intentionally selected LP operation.

jerryjay11 wrote:
Make sure the circuit breaker is "on" for the HWH. When plugged in to power it should automatically select electric unless you have intentionally selected LP operation.

Nonsense. The OP's Atwood GC10A-3E is a 10 gallon DSI propane powered water heater with the 120 vac electric heating element option. There is nothing "automatic" about it - there will be a GAS switch to run it on gas only, an ELECTRIC switch to heat water with the electric heating element, or one can run it in both modes at the same time for quicker recovery. However, one must manually turn either of these on / off as preferred. An Atwood also doesn't have any switch mounted on the outside of the unit itself as does a Suburban water heater, both switches will be mounted inside the trailer.

Mbiallas wrote:
Also on the panel to turn the heater on or off I noticed a small red light just right of the toggle switch. What does this light indicate? Sometimes it's on and others it's off.

The light indicates that the propane burner ignition sparker is on. It should go out as soon as you hear the burner kick in.

That switch is most likely for propane operation only and would remain off when running on the electric element.

Some coach builders put the electric switch in the electrical bay so you will remember to turn it on when you're hooking up.

Also, if you go to the upper right of this page, click My Forums and go to My Preferences, there's a box for your signature. If you put your rig description there, it will make it easier to answer RV make and model specific questions like this one.

Atwood GC10A-3E........Gas Combo 10 gallon version 3 Electronic Ignition

GAS ON/OFF Switch With FAULT LIGHT inside RV
FAULT LIGHT comes ON when propane fails to light off and PROVE it lit


Electric On/Off Switch AND set of 120V AC Normal temp & High temp t-stats are located on backside of water heater (access from inside RV)
On/Off switch is on cover and element /set of t-stats under the cover
IF the High temp t-stat Opens it has to manually be reset (push button in center of t-stat)


So gas can be turned on Inside the RV via wall switch but electric has to be turned on by accessing backside of water heater to use switch on cover.
You can 'add' an additional on/off switch in a more convenient location wired in 'series' with OEM switch
Take wire from 120V Circuit Breaker to NEW switch then from switch to OEM switch.
Both switches have to be ON for power to element (just leave OEM switch ON) and control element with new switch.
Many times a standard residential light switch is used.

Do you have a 'light switch' on cabinet in kitchen area?



With a combo unit you can heat water with:
Electric only.....6 gal/hr recovery (cold fill)
Propane only.....10 gal/hr recovery (cold fill)
BOTH at same time...16 gal/hr recovery (cold fill)

I am seeing exactly what Old Biscuit is talking about inside. The previous owner marked the switch position backward but I have it turned on now which was verified with a meter. But I am still not getting hot water. Do the propane and ac systems work independently from one another? In other words does an inside ac thermostat have any effect on the outside lp thermostat?

There are three powered devices behind the cover. Two are thermostats and I assume the other one (at the bottom and much larger) is the heating element. I can confirm cuttent at what I think is the element but is still will not heat the water. Any recommendations?

ON YOUR MODEL
Electric & those two t-stats are completely independent of the propane & two t-stats in outside compartment


...confirm current at element but not heating water...???

120V AC comes from a Circuit Breaker to that On/Off Switch to the 'normal' temp t-stat---to 'high' temp t-stat (manual reset) then to the element (Black wire) thru element and back to AC Power Panel on Neutral (White wire)

Check that the Ground wire (Green) is clean/tight....no ground no heating


Wiring diagram...pg 8
Parts ...........pg 9&10
https://www.manualslib.com/manual/1014400/Atwood-G4-7.html?page=8#manual

The ground was neither clean nor tight. All is put back together now with 110 volts going to the element. Any suggestions if this doesn't work?

Mbiallas wrote:
The ground was neither clean nor tight. All is put back together now with 110 volts going to the element. Any suggestions if this doesn't work?

Replace element if in 30 minutes you do not have heated water

Normal temp t-stat (controlling t-stat) opens when water temp reaches 140*F (both electric and propane)

High temp....opens at 180*F (Trips to shut down heating cause normal temp t-stat failed)