Today I replaced my on board water filter with a Shur-Flo accumulator. Once I was done I plugged the camper into house power and noticed that the water heater came on. I went outside and checked the switch and it was off so I unplugged the water heater and of course it went off. I plugged it back in and checked power at the element, I have 120volts on the white wire and no voltage on the black wire, 120volts across the element. I then pulled the wires off of the element and tested for short to ground, none and Ohms across the element 10.4ohms. I pulled out the switch and it works as it should. I know for sure it hasn't always been like this because I would have melted the element by now. The thermostat and junction box is only accessible if I pull the whole heater. The gas side works fine and is what I will use if I can't figure this out before this weekend. Any help would be appreciated.

There should be no power on the white wire.Check the receptacle you are plugged into start with.Are you using an extension cord? two or three wire? Two wire, get a three wire!Do you have one of the three light yellow receptacle tester? If not get one!

I pulled the receptace that the heater is plugged into and it has the correct polarity. I have everything plugged in the same way I have been doing it for three years now, same outlet on shed, same extension cord, same adapter. I checked the polarity of the GFCI in the bathroom as well and that was fine.

On our water heater the AC heating element is turned off or on with a breaker in the main power pannel. The DC switch and igniter indicator light only controls the waterheater when it is running on propane.

My HWH has TWO switches, one on the wall by the kitchen sink, the other one is located on the HWH itself. When putting the trailer away for a while, i always switch the HWH off at the heater, just in case that the wall switch somehow turns on by it self. ( KIDS. )

Curious, HOW did you know the 120 side was on?????? There is NO indication of if on or off unless it does NOT heat. You stated something odd. You said you had 120 at the White but NOT the Black. Then stated you had 120 between the white and Black. That is at odds with the statement. You cannot have it both ways. Then you said you cannot access the Junction box or tstat without pulling the W/H. But you accessed the Element? IF you have a older Atwood, the the tstat and junction box AND the element are all at the rear. If you have a newer Atwood the tstat is on the outside and the 120 element and junction box are still at the rear. If you have a suburban, the tstats and the element are all easily accessed at the outside area. ONLY the 120 junction box is available if pulled. SO, what brand and model and year do you have? Doug

Water Heater Always On | Good Sam Community

18 Replies

electrician549
Explorer
Oct 15, 2013
It is a Suburban water heater. I don't have another switch for the 120volt side besides the one on the outside of the heater. I am positive the switch was off checked the switch several times. I can't access or even see the 120volt junction box or thermostat with out pulling the water heater, which is my last resort. When I get home from work I will try a couple other things. I went out last night and double checked polarity on the camper and the outlet and both were fine.
Old-Biscuit
Explorer III
Oct 15, 2013
Bonefish wrote:
On our water heater the AC heating element is turned off or on with a breaker in the main power pannel. The DC switch and igniter indicator light only controls the waterheater when it is running on propane.

What Brand of water heater?
Suburban will have an ON/OFF switch in outside compartment.......lower left corner

AC circuit breakers typically are not used as ON/OFF switches......strange or I guess cheap install.
Old-Biscuit
Explorer III
Oct 15, 2013
Are you sure ON/OFF switch wasn't ON?

You should have 120V AC to/thru ON/OFF switch----to/thru the 120V set of t-stats and thru to/thru electric element. Black wire should be power to element----white wire neutral from element.

10.4 Ohms is low..........continuity test of element should read between 14.5-17 Ohms
dougrainer
Nomad
Oct 15, 2013
Curious, HOW did you know the 120 side was on?????? There is NO indication of if on or off unless it does NOT heat. You stated something odd. You said you had 120 at the White but NOT the Black. Then stated you had 120 between the white and Black. That is at odds with the statement. You cannot have it both ways. Then you said you cannot access the Junction box or tstat without pulling the W/H. But you accessed the Element? IF you have a older Atwood, the the tstat and junction box AND the element are all at the rear. If you have a newer Atwood the tstat is on the outside and the 120 element and junction box are still at the rear. If you have a suburban, the tstats and the element are all easily accessed at the outside area. ONLY the 120 junction box is available if pulled. SO, what brand and model and year do you have? Doug
mpfireman
Explorer
Oct 14, 2013
My HWH has TWO switches, one on the wall by the kitchen sink, the other one is located on the HWH itself. When putting the trailer away for a while, i always switch the HWH off at the heater, just in case that the wall switch somehow turns on by it self. ( KIDS. )
Bonefish
Explorer
Oct 14, 2013
On our water heater the AC heating element is turned off or on with a breaker in the main power pannel. The DC switch and igniter indicator light only controls the waterheater when it is running on propane.
electrician549
Explorer
Oct 14, 2013
I pulled the receptace that the heater is plugged into and it has the correct polarity. I have everything plugged in the same way I have been doing it for three years now, same outlet on shed, same extension cord, same adapter. I checked the polarity of the GFCI in the bathroom as well and that was fine.
enblethen
Nomad
Oct 14, 2013
There should be no power on the white wire.
Check the receptacle you are plugged into start with.
Are you using an extension cord? two or three wire? Two wire, get a three wire!
Do you have one of the three light yellow receptacle tester? If not get one!

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Water Heater Always On

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