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Aqua hot Intermittent operation on burner


My AH will fire up on diesel and run for a while but will then shut down with the light over the galley turned off.

I called Rudy @"Trainer" and he said it sounded like a photo detector to him.  

The troubleshooting is relatively straight forward.   

1) With the burner firing, measure the voltage on the black wire on the “C” connector.  Compare that to the green wire on the ‘C’ connector.   The green wire is the voltage coming from the photo eye.  It should be fairly close to the voltage on the black wire and remain steady.  My black wire was at 12.4 volts and the green wire started at 10VDC but then started dropping as the burner got warmer.  Looks like a bad photo-eye.

2) The other way to test the photo eye is to remove burner and disconnect the photo eye.  Measure the resistance on the photo eye with the photo eye exposed to a bright light and to total darkness.

For bright light you are looking for less than 200 Ohms
With the light blocked you are looking for more than 100K Ohms.

My photo eye measured 80 Ohms in light (good) and 45K Ohms in darkness (not good).

So I will be contacting Rudy to get him to send me a photo eye.

Will post more when I get it installed and it works.


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Bill Johnson
Birmingham, Alabama

My aqua hot is doing the exact same thing. Did this fix your problem?

Thanks, Tim

New Owner of Coach 530 (1999) Formally owned by and Meticulously cared for by Russ.
I Own two RV Parks.
Acacia in Alamo TX
Lone Star in Dilley TX

Tim Call me between 8 and 8. Rudy Legett 7 one 3 8 one 8 3234. Talk to you then.

Rudy Legett
2003 Foretravel U320 4010
ISM11 450 hp Allison 4000R
Factory Authorized Aqua Hot Repair Center
Southeast Texas Area

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