Community Forums

moleary · 03-05-2021, 07:13 PM

I’m chasing an electrical gremlin on my Aquahot 450D. The electric side works fine. I usually keep the burner switch turned off unless someone is showering. Lately, however when I flip the diesel burner switch inside the coach the light in the switch doesn’t light and the burner remains lifeless. I thought I traced the problem to a defective interlock switch on the aquahot cabinet. I could wriggle the switch and the diesel system would begin its routine. (Near as I can tell the interlock switch has nothing to do with the electric side) I cleaned the switch and everything seemed back to normal. Of course it wasn’t, or I wouldn’t be posting here. Believing the switch was faulty, I simply hotwired around the switch until I could buy a replacement. However I experienced the same problem even with the switch eliminated. The diesel system initially worked but went dead. The panel near the aquahot remains powered at all times and shows no red light faults. I have pushed the low voltage reset with no change. I have switched the interior power switch off for 5 seconds as a reset. Nothing. Then, without explanation, it will mysteriously begin to work. The schematic shows a fuse between the 12v source and the interlock switch. I wondered if it may be loose and making intermittent contact, but I can’t find the fuse. I can’t get back in there enough to look. Does anyone know the location of the fuse? Any insight will be most appreciated.

TampaDave · 03-06-2021, 10:17 AM

When this has happened on my unit, it's been a burner fault. Not lighting up, or knowing that it's lit. Not getting fuel (eg air in line), nozzle plugged, electrodes dirty or not gapped right, fuel sensor reflector dirty, those are the sort of things I'd wonder about. Annual maintenance sorta covers the waterfront.

Hear what you're saying about the interlock switch, was wondering about that myself. Getting it serviced, and then using it seems to have fixed the problem.

moleary · 03-06-2021, 11:18 AM

A service is definitely in the works. Admittedly, I’ve gone too long without doing so. Got a week left in Florida this winter. Gonna try to limp it along on electric for the remainder of our time here and go through it when we get home.

You got me thinking more about the interlock switch. I wonder if a fault like you mentioned shuts everything down and when I open the cabinet and, in doing so the interlock switch, if that interruption in power resets everything and the burner sequence manages to get a “good read” and fire? Only thing is I’m not getting a fault light on the panel. Just thinking out loud here.

TampaDave · 03-07-2021, 06:17 AM

When you get a burner fault, I think that's indicated by the diesel burner status light going off, both on the panel down below, and the switch above. I don't think those LED's turn red unless a short circuit is detected

Interesting thought re: interlock switch resetting everything.

**Spdracr39** · 03-07-2021, 06:54 AM

My Hydrohot was doing something similar. No indication of a problem but the blower would not start its purge cycle. If you went outside and messed with it it would run and may or may not come back on the next cycle. I figured out if I smacked the blower housing with my fist it would start up. Further diagnosis finally lead me to the motor having a "flat" spot and after replacing it no more issues.

Mikegrauer · 03-24-2021, 08:25 PM

So I have the exact same issue no warning lights randomly working, my indicator is light Inside goes out , works fine on electric my door switch was a issue I have bypassed with a fuse installed as the door switch is not a ground interupt it's a hot lead, anyway mine fires when it wants and last no longer then a few cycles . I bought my rv used and still trying to get everything to work, everything is broken and not working. So what resolution did you come up with? I will hit the motor tomorrow to.see if a possibility of a flat spot ? I have changed the check valves and both were stuck and I changed out the coolant and bleed it then. System was broken beforr that repair was done. I know I need to change my fuel nozzle and filter but I don't want to do it until I find the issue of the motor not spinning. When it spins it starts everytime . Would love some advise . I'm new to this forum but not to rvs had a ton of rvs and this one was a fixer when I got it and I know what to do on most things .

moleary · 03-28-2021, 06:20 AM

I am the original OP. After returning home from our winter escape, I replaced the filter and burner nozzle and cleaned the burner chamber. So far so good.

Mikegrauer · 03-28-2021, 08:53 AM

I'll likely do both I've used the rv this weekend and it's still not staying on but the trick of hitting the motor does make it start everytime so I'm thinking I have the flat spot as mentioned in here because it starts everytime firing up after the motor starts spinning , it's just getting it to start spinning