Aqua Hot Issues

[pete5016]

Good Morning - first cold morning in a while and I am having some issues with my AquaHot heating system.

When I went to bed last night, I was using the AquaHot to heat my Tiffin. I was only using the electrical element. It was working well when we went to sleep. Upon waking, my RV was a little cold (around 60 degrees - thermostat set to 70) and I noticed the fans (that pump the heat into the RV) for the aquahot were no longer running. I turned on the Diesel Source for the Aquahot and the fans and heat started back up, but only ran about 5 minutes before the diesel shut itself off and the fans stopped again.

It appears that the diesel won't run for more than a few minutes before clicking off.

So, unsure why the heat stopped when using the electric (checked the fuses - no 120V switch tripped) and not sure why the diesel is not working. I am still getting plenty of hot water.

Any advice or insight?

[rfg9585]

This happened to me and I just kept turning it back on until it stay on. Had it serviced later with new nozzle\cleaning\etc and hasn't happened since.

I guess mind just clogged up a bit and had to burn it off to keep it going.....

[bentjm]

The electric element does not provide enough BTUs to heat your coach - that is what your diesel burner is for.

You probably need to do a general service on the diesel side.

[Ivylog]

The fans should not stop running if everything is OK. On the control board, what lights are on? Sounds like a fault is shutting it down... low voltage, liquid level low, or high temperature sensor defective.

[Mr Ted]

Originally Posted by bentjm

The electric element does not provide enough BTUs to heat your coach - that is what your diesel burner is for.

You probably need to do a general service on the diesel side.

^ This ^

[Outbound]

Have you tried moving temp setting up, may be stat has a problem.

[Gary RVRoamer]

The electric heat may indeed be insufficient for really cold weather, but that shouldn't cause a fault and stop the fans. Something is wrong with both electric and diesel modes, maybe the same thing or maybe two different things. I'd start with Ivylog's suggestions to figure it out.


There are service manuals with troubleshoot info on the Aquahot website.
Aqua-Hot Manuals

[96 Wideglide]

Did the burner start back up?

The burner shutting down after only a few min is normal. The electric element almost had the boiler fluid up to full temp. The heat exchanger fans shutting down while the burner is running, and your inside temp about 10deg below thermostat set temp, that shouldn't have happened.

[757driver]

There is nothing wrong with your electric heating element on your Aquahot. It does not have very many btu’s so when cold outside it will not be able to keep up with the heating demand. If the Aquahot fluid is not hot enough it will not circulate thus the pumps will not run and the heat exchanger fans will not run.

Think of it this way, when your Aquahot is first turned on it does not start circulating fluid nor do the heat exchanger fans turn on and blow cold air. When the fluid reaches temperature everything turns on and circulates.

With just the electric element on when it is reheating fluid the circulation pumps and heat exchanger fans turn off until the fluid is heated back up and then will turn back on for a few minutes until the fluid cools off.

[pete5016]

Originally Posted by 96 Wideglide

Did the burner start back up?

The burner shutting down after only a few min is normal. The electric element almost had the boiler fluid up to full temp. The heat exchanger fans shutting down while the burner is running, and your inside temp about 10deg below thermostat set temp, that shouldn't have happened.

No. The switch where I turn on the Diesel is illuminated. Even though the switch was on, the light turned off. I have not seen the system do that before.

The system was also producing a lot more smoke running on diesel than usual. It looked I was spraying the campground for mosquitos.

[NLOVNIT]

Originally Posted by bentjm

The electric element does not provide enough BTUs to heat your coach - that is what your diesel burner is for.

You probably need to do a general service on the diesel side.

The electric element is about the equivalent of a blow dryer or space heater on high. You won't be able to heat your whole coach with either.

When was the last time your unit was serviced? That'd be where I'd start. There's a whole bunch of other things that could be checked (that's in another AquaHot issues thread in the Systems & Appliances Forum) for the burner shutting down, but first things first with maintenance.

Lori-

[Spk64]

Diesel light going out is an indication of a fault on the Webasto Burner Control Unit.
The fault could be from multiple locations.

[pete5016]

Originally Posted by 757driver

There is nothing wrong with your electric heating element on your Aquahot. It does not have very many btu’s so when cold outside it will not be able to keep up with the heating demand. If the Aquahot fluid is not hot enough it will not circulate thus the pumps will not run and the heat exchanger fans will not run.

Think of it this way, when your Aquahot is first turned on it does not start circulating fluid nor do the heat exchanger fans turn on and blow cold air. When the fluid reaches temperature everything turns on and circulates.

With just the electric element on when it is reheating fluid the circulation pumps and heat exchanger fans turn off until the fluid is heated back up and then will turn back on for a few minutes until the fluid cools off.

Makes sense...Thanks for the explanation!

[bentjm]

Originally Posted by pete5016

No. The switch where I turn on the Diesel is illuminated. Even though the switch was on, the light turned off. I have not seen the system do that before.

The system was also producing a lot more smoke running on diesel than usual. It looked I was spraying the campground for mosquitos.

The smoke is a big indicator that the diesel side needs some attention. Most likely, your nozzle needs to be replaced. It is a pretty simple job to do yourself.