Aqua Hot Diesel Burner Stopped Working - AHE-100-04S

[Mike Nilson]

Hello All,

My wife and I full time in our Beaver. This morning we noticed the RV was cooling down and not staying worm. Checked the Aqua Hot and found the diesel burner is not turning on. No low power faults, or any other faults that I can find. The electric elements seem to be working correctly and trying to hold the load but cannot without the burner.

I did press the reset for low power just in case and no luck. The tank is full of fluid and none of the sensors are tripped. The control board shows all green lights on the electric status, and the burner status, but the burner remains completely silent and non-functional.

I serviced the burner last spring in May of 2021 by replacing the Nozzle, Filter and everything that an annual service is supposed to have done. Absolutely no issues until today.

Does anyone have any experience that may help me troubleshoot this and solve it?

[Frank Bergamo]

Mike,

Just covered this awhile back. This might help you. Good luck. http://beaveramb.org/forum/index.php/topic,11048.msg74855.html#msg74855

[Fred Brooks]

    Mike,
If you can go to our technical library and look up the service manual for the model of Aqua-hot you have, section 7.1 has the complete guide for trouble-shooting your issue. Fred

[Mike Nilson]

Thanks for the thread link

I was able to get it to fire today, but I now believe something is wrong internally with the blower motor. There is an abnormal humming or buzzing sound that might be caused by a bad bearing on the shaft for the fan or the electrical motor itself is failing. The electrical side is all testing out correctly. I've uploaded a short clip to YouTube https://youtu.be/20tT-bgsyxo

I first consulted the manual, which told me to contact tech support. Tech support gave me a long list of probable causes. They suggested I remove the housing around the blower and check the bearings, which I will do tomorrow, which could be ceasing causing the unit to fail to run.

If anyone else has experienced this particular issue and have some suggestions, please let me know. Presently I'm thinking a rebuild of this blower motor is in my future.

[Stan Simpson]

Mike, I experienced the humming/buzzing sound. It occurred after the Hydro Hot running and going in to the purge cycle, I had it serviced and was told that the WABASTO control module that is attached to the side of the combustion chamber was failing, and I would experience intermittent non-firing episodes until it finally went bad. I purchased a replacement, and the old one lasted about 2 months before it expired. I'm not an expert. Just passing along the result of a similar symptom.

[Eric Maclean]

Mike
Once you get the cover off the burner assembly use a long screw drive as a stethoscope by placing the handle against the back of your ear and touching the other end to the suspected problem area on the blower housing etc.

There are a couple of suspect areas in a Wabasto 2010 burner to check
1) the motor itself  ( they are a permanent magnet motor and occasionally the magnets come loose from the litter housing)
2) the blower bearings may be worn out and ready to pile up
3) the fuel pump although they usually develop a leak before they make that much noise.

This is a link to the DBW 2010 Wabasto heater the burner is the one Aquahot uses


https://www.google.com/search?q=wabasto+dbw+2010+service+manual&oq=wabasto+dbw+2010+service+manual&aqs=chrome..69i57j0i22i30l2.26518j0j8&client=tablet-android-lenovo-rev2&sourceid=chrome-mobile&ie=UTF-8


Hope. This helps
Eric

[Fred Brooks]

    There is also a 3 fingered coupler that joins the output of the Wabasto motor. When one of the coupler tabs breaks, it makes a weird harmonic noise. Fred

[Mike Nilson]

Thank you all for your comments, they help me narrow down where I should focus my time. I meant to reply earlier after I was able to fully diagnose the issue, but got busy and time slipped away.

The electric motor was failing under load. It was difficult to diagnose because when the motor was off the blower housing and when the blower was completely removed it would function normally without evidence of being faulty. It wasn't until the motor was placed under the strain of the diesel pump attached to the fuel supply that it would act up and create the weak output and humming noise seen/heard in the video attached above. I replaced the motor with the new version and no more issues. Also as a precaution I replaced all barring's, washers, gaskets, and re-greased the gears. I also parts washed the whole blower housing.