AquaHot trouble

[Albert Balika]

When I turn the AquaHot on, the green light illuminates, the pump activates but system does not fire, the green light goes out but the pump continues to run forever. After significant time, I push the button and the green light illuminates. I then immediately push the button again and the system then cycles off after the normal three minute time frame. I just had the system fully serviced a month ago and it operated fine until this situation occurred. Any thoughts on what might be going on?

[David T. Richelderfer]

AquaHot model ID?  Propane or diesel?

[Mike Shumack]

I have the AquaHot (diesel) model AHE 100-04S. I just went through this. When you turn on the AquaHot the blower will start running (which also runs the fuel pump) and the igniter will start sparking (you can here it clicking) and the fuel solenoid will open. If the unit does not detect a flame in about 30 seconds, the fuel solenoid shuts and igniter will stop - and the light on the switch turns off. The blower will continue to run for a while to clear out any fuel that my have sprayed in the combustion chamber but didn't ignite.

Assuming you have fuel to the AquaHot, a common cause of a failure to ignite is a dirty fuel spray nozzle. If the fuel is not sprayed as a fine mist it wont ignite. You can replace the nozzle for under $20 bucks. The other parts are crazy expensive.

Here is a link to a good video on how the system works and how to troubleshoot.  https://www.youtube.com/watch?v=nj_BqehNu64

[Albert Balika]

Mike, Thank you for your response. What you described is the normal sequencing. My situation is a bit different in that the igniter does not click. It is the pump only that continues to run (forever) until I push the button and the green light illuminates at which time I push it again, as I stated, and the system shuts down, as designed in approx 3 minutes. So, the question is - why doesn't the system shut down at the initial try when it does not fire? And, why does the igniter not click and fire during this initial start up? The nozzle was replaced a month ago during full service including filter, fuel flow check, voltage, etc., etc. All comments are welcomed.

[David T. Richelderfer]

Another thought:  If the igniter module has weakened, then it becomes intermittent in its ability to ignite the diesel.  When I had Mike Flowerday service my Aquahot several years ago, he noted that my Aquahot's igniter module wasn't firing properly on every startup.  He indicated that in warmer conditions, then the igniter would likely work fine.  But in colder conditions, like in the cooler morning hours or when in a colder climate, when I need the Aquahot to work, then it might not ignite the diesel properly.   At the time, I had an extended warranty and the warranty company sent an "auditor" to confirm those expensive parts were bad and required replacement.  Mike had to show the auditor the igniter was intermittent before the auditor would authorize its replacement under warranty.  It was in the warm afternoon in LaPine, Oregon, and took Mike about 30 starts of the Aquahot to finally fail to make ignition.  The auditor immediately authorized the replacement.

My Aquahot is the AHE-100-02S model.

[Mike Shumack]

Albert, what model do you have? Since your coach is newer, perhaps a 450D.
Do you have any lights on (green or red) on the status-controller board?

[Keith Moffett]

Albert
Likely you have the AHE100-04S  as mentioned above.  We have the same.
If you do any work of your own on the AH then try unpluging the computer and make sure the contacts are clean then reconnect it in a few minutes. 
Also just FYI I have gotten a bad nozzle before. 

[John Shannon]

I believe that all 2007 to 2009 Contessa use a model 450DE