Electric Water Heater Problem

[drjp]

Hi. I’ve got the dual, electric/gas, water heater in my 2017 17B. Since several months I’ve noticed that the electric side doesn’t heat (after waiting 20 minutes), but as I usually use propane, no biggie. Still, I’d like everything to be tip-top as I’m looking to sell it soon. I’ve turned off the LPG at the bottles and am only turning on the electric heater switch outside on the unit itself. I am testing using the internal water tank and pump. I’ve flipped the ‘HW’ 15 amp circuit breaker (actually, all the breakers) several times, have always had it on shore when testing it. The power controller shows “E 0” (no errors), 121 V. Because I know nada about the circuitry, I checked all the blade fuses, too, and they’re OK. I’ve got 121V at several internal AC sockets.

Dustin at ETI said it’s often the water heater element, so I replaced that. On shore with the outside heater switch on, no volts at the two heater element terminals (with the wires attached).

D. thinks that it might be the reset switch assembly itself that’s gone bad, but that’s pretty uncommon he says. Dear colleagues, any ideas otherwise before I pop for a reset switch?
Thanks!
Jonathan

[gbaglo]

I just heat water with propane in the morning, half an hour before a shower and shut it down unless we need to wash dishes after dinner. In that case, I'll turn it on again for 15 or 20 minutes.

[drjp]

Yep, propane for us, too. But the heater’s got that electric element and I’m tryin’ to get it going. Wonder what’s wrong?

[alanmalk]

Originally Posted by drjp

Yep, propane for us, too. But the heater’s got that electric element and I’m tryin’ to get it going. Wonder what’s wrong?

One easy thing to check is the state of the newly installed heating element.

First, disconnect the trailer from shore power. This is to keep you alive.

Second, disconnect the two wires from the element. This is to keep anything from influencing your measurements.

Third, use your ohm meter to measure the resistance between the two terminals on the element. It should read about 12 ohms. Anything close is good. Zero or infinity is bad.

Let us know what the reading is.

[rubicon327]

The circuit for the 120V operation is pretty simple. You can ohm out the element although it’s probably not that since you have no voltage at the element terminals. Check that the reset is pushed in. The one for 120V operation is on the left when facing the hot water heater. You have to feel under the black rubber cover piece and make sure nothing is sticking up under it which would be a popped reset. I haven’t heard of the thermostat/ hi-limit unit going bad but it’s possible. I have heard of the small on/off switch going bad. It’s tough to replace apparently. Be safe when dealing with electrical!
This video should help:

https://m.youtube.com/watch?v=j5jN3tHVAnU

Also this troubleshooting and repair guide put out by Heartland for Suburban water heaters is good:
https://manuals.heartlandowners.org/...ban%20V1.3.pdf

[Vermilye]

It is possible that the thermal reset has opened - there are 2, one for the propane side & the other for AC. Pushing them in will reset them.

If you have replaced the heater element & with the breakers on & the trailer plugged in, and the EMS readout doesn't show a voltage drop (or current increase) as you turn on & off the water heater breaker, it likely the off/on switch on the outside of the water heater is bad or the terminals connecting to it have failed). This is a common problem since the switch is working close to its rating and is fairly low quality.

[drjp]

Thanks to you all for your kind replies.
1. MMeter showed 0-infinite ohms across element’s terminals after replacing it.
2. Yep, I’ve carefully insured multiple times that the reset buttons are pushed in. Solid, but I didn’t remove its cover to consider replacing it.
3. Vermilye opines that the more likely culprit is that the power switch has failed as it’s a cheapo. And even I can see—as one of you said— that it’d be tough to get out.

But the heater works fine on propane so I’ve put it up for sale (with disclosure to be sent extra to interested parties) on the forum and at ETI classifieds. Thanks again for your informative help. It just shows why this forum is a go-to source for RV owners of many various makes and types!
Best, Jonathan

[alanmalk]

Originally Posted by drjp

Thanks to you all for your kind replies.
1. MMeter showed 0-infinite ohms across element’s terminals after replacing it.

...

The resistance of the heating element should be in the range of 5 to 20 (actual number is not important). A reading of zero or infinite indicates trouble - and could explain why no hot water (but is not explaining having no voltage: that's either switches or wiring).

[drjp]

Originally Posted by alanmalk

The resistance of the heating element should be in the range of 5 to 20 (actual number is not important). A reading of zero or infinite indicates trouble - and could explain why no hot water (but is not explaining having no voltage: that's either switches or wiring).

Yep, doesn’t indicate where the circuit is stopped. Suspicion lies with a switch failure.

[Vermilye]

Is it "0" or infinity? If the multimeter shows infinite ohms across a disconnected new element, it is bad. It should have between 10 & 20 ohms of resistance. Some meters are not very effective measuring a low resistance & might show "0" ohms when it is actually 10 - 20 ohms...