110 volt AH breaker #six under the end of the bed has popped a couple of times in the last week. Right now I have it turned off in case of a escalating issue.
1st assumption: I need to replace the electric element versus some other issue (like perhaps a weak breaker on #6)
Also I "assume" I will have to drain the AH coolant to replace the element. How many gallons? Anything else nee to be rep,oved besides AH cover to get to it?
I'll be contacting Rudy, but also posting here for future searches and advice.
Found this one form a few years back: Aqua Hot Electric Heating Element Upgrade (https://www.foreforums.com/index.php?topic=39669.msg391217#msg391217)
Sent you a PM too.
Remove the small cover where the 120 vac enters the top of the heater. Examine the wire screw connections. Many times the problem is there.
If elected cynical entrance is okay, remove cover to open area where the burner is located. Remove the thermostat cover located above the burner. Examine the wires going to and from the two thermostats on the right hand side of the thermostat area. These stats have screw connections. One wire comes from the entrance, one wire goes to the element and the other wire connects from one stat to the other.
If element bad, all 16 gallons of coolant need to be drained. Probably not the problem.
Rudy has given me more to check via PM. Will be tommorrow at earliest to do it.
Thanks Rudy!!!
Dan, call me please. Rudy 7 one 3. 8 one 8. 3234
Dan,
It wouldn't be the first of those breakers needing to be replaced due to aging out. The vibration and temperature from the engine do shorten their lifespan. IIRC, we replaced one for a roof A/C and one for the circuit that included a leg of the powerline monitor, and those would have been 8 or more years ago.
Michelle
(ETA - looking at the schematic page, I'm pretty sure #9 (power monitor and engine block heater) and #10 (front roof A/C) were the ones we replaced previously. All the others are the originals.)
With his wires looking very pristine, I think Michelle has hit the nail on the head.. Talked to him on the phone and a 10 minute test of the circuit breaker will provide the answer about the breaker.
Unfortunately it is not the breaker.
Swapped wires for #4 breaker rear air con and # 6 breaker AH in the breaker panel.
The problem moved to the other breaker (#4) , rear air con ran fine on #6. Swapped them back after the test.
Done with troublshooting for today, have other things going on. Rudy gave me some next steps (ohm meter on element wires).
Well bless pat. My phone is on if you need any more assistance.
Problem resolved with Rudy's guidance on troubleshooting.
Short version: 110 volt wire from thermostat to 110 V heating element was the cause.
Long version that may help others troubleshoot any similar/different AH issue. Rudy's advice on all.
1. Where 110 volt wires enter the AH, remove side cover and check the 110 volt wire nuts for good contacts. (need short handle phillps screwderiver). All was good. (breaker off)
2. Top outer edge (on our coach) of AH remove small cover over 4 thermostats. Phillips screwdriver. All connecctions were tight. (straight blade and phillips)
3. Inside coach below bed, 110 volt circuit breaker box, check if bad breaker. (unplug shore power first). I swapped wire for rear AC with wire for AH. Problem moved to new breaker, AC ran on suspect breaker. Put wires back in place. (straight blade screwdriver).
4. Inside AH, to bottom right of burner assembly is small cover over electric element. I moved the control box out of the way for access. (***110 v breaker off) (phillips screwdriver)
4a I disconnected the white wire (ground) from element and checked continuity of the two terminals on element. It read around 9 to 10. I also tried breaker and AH again with white wire removed, breaker still popped. Called Rudy, he said continuity was correct.
4b with Rudy still on phone, he recommended (with breaker off) pull black hot wire off element and try breaker again, Breaker did not pop. Breaker off, reconnected both hot black wire and white ground wire, and tried breaker once again. Breaker did not pop.
5. This indicated a issue with black power wire from lower right thermostat down to 110 volt electric element (about 14" wire, easy access). Assumption was wire had a short to AH case. I thanked Rudy and let him go from the phone call.
5a. With breaker off, I replaced that wire from thermostat to element with new wire and ring terminals. (flat blade and phillips, crimpers, wire, ring terminals) All is still working couple of hours later.
6. Rudy and I both expected bare wire from scrape or heat on the wire. Wire "looks" fine, one end ring terminal has some corrosion. I tested that wire on my car battery and it conducts 12 volts ok. I guess heat damage, degragation, and some corrosion on one of the end terminals.
Very happy that this ended with no $$ and only time plus Rudy's advice and expertise. I would not have found it without Rudy's help.
Thanks Rudy!!!!
If you had taken that to a shop, many dollars later you would have gotten out of there.
And it probably wouldn't have been fixed until they threw all kinds of parts at it. Rudy is a gem!
I'm not sure how many hours it would have taken them to suspect the wire itself from thermostat to electric element.Not something to normally suspect. They may have replaced the 110 volt heating element suspecting it., requiring complete coolant draining.
In hind sight, when I checked tightness of the terminals on thermosttes and electric element, I "could" have pulled them off to inspect for corrosion and cleaned up the connections. I was concerned moving them around would damage the plasctic over the wire connections as all have heat damage and may break apart on movement. I also could have used a bright flashlight to visually inspect them all. And perhaps a shot of contact cleaner on each.
After this long all the wires and plastic parts are heat damaged. Not surprising they continue to work. Rudy is da man.
Wonder how long these go before needing a major overhaul?
Rudy/Dan,
Thanks for the knowledge sharing! After following the steps, I think may have the same issue. The breaker is popping and I have 8.5 ohms on the continuity of the electric element itself.
- What gauge wire did you use for the 14" section? I am assuming 12 ga. since the breaker is 20 amps.
I do need to check on my 198 º F Electric Element Control Thermostat for continuity. If that checks out, I'll replace the wire.
Separate question: I noticed that the wiring for the AH has
white Romex which is usually indicative of 14 ga. wire for 15 amp circuits. I'm making an educated guess that the 1996 coach was made as the color coding standards were evolving.
The History of Romex Cable and the Evolution of Color Codes According to the... (https://wesbellwireandcable.com/blog/the-history-of-romex-cable-and-the-evolution-of-color-codes-according-to-the-nec/) [/list]
14 ga is okay. Just make very good connections
In the old days white non-metallic cable, "romex" could be anything from 14-2/14-3 to 10-2/10/3 wire. There is also white 8/2 & 6/2 cable.
As to what size of wire to use, it is based on gauge and insulation. If it was me I would use 12G THHN/THWN stranded wire. If you can find XHHW, it has a better insulation.
I did one last check and left the black wire from the thermostat to the element disconnected. The breaker did not pop.
The 198º F Electric Element Control Thermostat tested for continuity and it passed. I did replace the black wire with 12ga stranded wire and new ends. Installed it and the breaker pops. :'(
I did not check the AC High-Limit Thermostat for continuity. If one of the two thermostats go bad, does that cause the breaker to pop?
What else can cause the breaker to pop?
I did notice when I checked the inbound wires that the insulation looks very weathered/scorched (?). See photo. We do have the RV hooked up to shore power with the electric element turned on to keep the basement from freezing. Could this be from extended use?
When you state you replaced the Black wire are you talking about the wire from the thermostat to the heating element?
Did you check the white wire for bad insulation?
I figure you have a wire that has bad insulation and is grounding out. So check all the wires that are related to the 120VAC side of the A/H unit.
Miike
Mike beat me to the post button. I also have questions along the same line.
When you say the breaker pops I am assuming that as soon as you turn the power on the breaker trips (pops)?
Or does it take some time to trip?
Have you swap breakers around to see if problem follows breaker?
Did you replace both wires or just the one? I have seen where the wire insulation breakers down due to heat and once you put 120V to the wire it can cause a short. A typical VOM does not put out enough voltage to check for insulation damage.
The thermostat could also be going to ground when you supply power to it.
Have you tried disconnecting one, then both of the wires on the element and then check to see if breaker pops?
I only replaced the black wire from the 198 degree thermostat to the heating element.
The white wire looked OK by the element but I cannot see the entire thing. I'll likely go ahead and replace the wires from the VAC service input to the thermostats and the element.
The breaker pops immediately upon flipping the Aquahot electric switch under the bed.
I just replaced the black wire from the thermostat to the element.
I did replace the breaker with the same result.
When I removed either the black wire, the white wire or both from the the element, it does not pop the breaker. Only when I complete the circuit.
Unless the insulation on the wire has gone south, sure sounds like the element, but for 8.5 ohms on the element sure sounds about right. When you checked the element with the ohm meter you had the wires disconnected?
Using a megger is a better instrument when trouble shooting since it does the ohm test at a higher voltage.
megger meter how to use - Google Search (https://www.google.com/search?q=megger+meter+how+to+use&rlz=1C1CHBF_enUS877US877&oq=megger+meter&gs_lcrp=EgZjaHJvbWUqBwgCEAAYgAQyDAgAEEUYORixAxiABDIHCAEQABiABDIHCAIQABiABDIHCAMQABiABDIHCAQQABiABDIHCAUQABiABDIHCAYQABiABDIHCAcQABiABDIHCAgQABiABDIHCAkQABiABNIBCTExOTI5ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8#cobssid=s)
Here is a Klein megger for $161.00 If removing the element is a big project, may be cheaper to buy this tool to verify if element is bad.
Amazon.com: Klein Tools ET600 Multimeter, Megohmmeter Insulation Tester,... (https://www.amazon.com/Klein-Tools-ET600-Megohmmeter-Insulation/dp/B07ZZX5TK8/ref=sr_1_3?crid=2H4WOI8XTW3CD&dib=eyJ2IjoiMSJ9.Nf5Xf_i8Y2Zcb9rKZ7pkintZCdjH2aJN5vtAdV5njWsPIKUXiQH0yxPBQd_kM01pn9yB51H4qgrYhtx2IdUZ2-QHe9QVXU7vtDYKs_7up_QIr15Y5kWsUuaB2KNwLN2SWPhp1-p0E551ZZMAVRit954eOVLNHgIHOXpAMNNpU0gICHOKrppANCrDumTh12JNj0ncZaDZvB2H4ikAljJBGzsTYH537nz83CKlg_OICgU.XzosSwvgD5mVfdoyKc7fg6E8jtiqqT13FuzW7TFMgyw&dib_tag=se&keywords=megger%2Btester&qid=1743557802&sprefix=megger%2Caps%2C165&sr=8-3&th=1)
The element may be intact for the circuit from hot to neutral but is also may be shorted to the boiler case or shorted into the boiler fluid. The latter is the more common mode of failure. The shell splits or bursts open.
I did some additional testing today. (#'s from Dan's test steps)
Upstream test:
- I removed the inbound 12ga wiring from the Aquahot.
- Installed an outlet, tested the outlet - passed.
- Plugged in a space heater which pulled 12.8 amps and breaker did not pop. Passed.
4a) Element continuity: I double checked with both wires disconnected
Result 8.5 reading (Klein MM450 multi-meter)
4a) White wire removed from heating element, black connected to element
Result: Breaker
did pop, popping noise heard at Aquahot
4b) White wire attached to element, black wire removed from element
Result: Breaker did not pop
Yesterday, I did replace the 12a wire from the 198 degree thermostat down to the element. No change in result. The breaker still popped (so I don't appear to have the same issue as Dan's original post).
Recent activity ("What changed?"):
- The element was working fine until just recently when we noticed that there was no boiler fluid in the overflow tank. We did add 1.5 gallons of boiler fluid to get the overflow to the right cold and hot levels.
- I also performed a service on the diesel side by changing the fuel nozzle and adjusting the electrodes.
The unit was serviced by MOT in 2023 with a new burner.
The electric element went bad while we were at Foretravel later in 2023. The 20a breaker and electric element were replaced.
The element went bad in 2024 and we replaced it ourselves in Tennessee.
Now in 2025, the breaker is popping again.
If white wire is ground/return and black wire is power, it sounds like something internal (popping noise) is shorted to ground.
The element has a fault and shorting to ground, thus breaker pops.
Very likely the element is getting dry while it has power and burning out. Possible it was never purged completely of air when the burner was replaced. I would try and figure out where the 1..5 gallon of fluid went.
A common failure is cracking in the hose from the AH rad cap to the overflow tank, most typically at the radiator cap end. Fluid goes out when hot but air sucks back in when cold.
That said, one would more likely see that the AH fluid level never changed (so some fluid still in the overflow tank), rather than a completely dry overflow. Of course it could be a leak in the overflow tank itself, but you'd think there'd be evidence of this below the tank.