[smquandt]

I have an AHE-120-04X.  The Diesel side runs intermittently, electric side always works.  I carry a spare control box and have installed the new spare with the same results.  I can hear clicking which sounds like relays (might be the fuel solenoid) opening and closing but the burner does not start.  If I very lightly tap either control box the motor starts and the burner lights. It may go through 10-15 cycles then fail to light, tap and it works.  Hesitant to declare both control boxes bad as the spare is new.  Does anyone have any ideas?

[ian1959]

Hi My coach #1218 I have always had to press the on button on then press again off then press on a second time for it to turn the burner on, electric turns on 1st time every time.

[House Divided]

It does seem really unlikely both boxes would be bad, but the common link (the plug) that connects them could be an issue.

I would start by inspecting the plug closely, looking for loose or damaged wire connections.

[smquandt]

Dave, IAN

IAN, just had to recycle to off then on get it to start. Have to do this sometimes but not all the time.

Dave, I have a new wiring harness from another coach so I think I will replace the one I have so I have new plugs. I have suspected that but I have not checked for continuity to all connectors on the plugs.

[Trainer]

Steve, As Roger Berke suggested remove the Control Unit (brain box) from the burner. Now, the item you tap that starts the burner will show the culprit.

If tapping the box starts it, bad box. If tapping the black burner starts it, bad motor.

If the box is bad, I really like the new Aqua Hot designed and manufactured Control Unit, WPE 300 901. It is all solid state, no moving parts or relays. But it retails for only $934. It has been very good since they came out.

I can offer you one if you should wish.

[Richard]

I don’t know if you want to tackle my suggestion, but I will put it out there anyhoo. I had similar issues with my AH, an earlier version of your unit, and I retrofitted it with a different control unit. Not suggesting that you do that, but as part of the retrofit I had the occasion to have a good look at the internal wiring of the unit. The wiring that goes to the motor, the flame sensor, and the fuel solenoid. I saw two things which concerned me. One, the wiring was extremely light in gauge. Two, the heat had made it brittle over time. I took the time to a buy high temperature silicone insulated 16g wire, and replace the internal wiring.

I mention this because the culprit you are describing sounds like it could be an intermittent connection. Personally, I would “upgrade” the wiring before did anything else.

Don’t know where you are, but if you are in Florida, I can hook you up into a data logger wired into the system that will tell you EXACTLY what is going on with flame sensor, fuel solenoid, and ignition coil.

[smquandt]

Had it apart in late November to replace the flame sensor. Aquahot thought that might be the issue. The wiring looked to be ok. We had to go home for a month so I didn't get a chance to do any troubleshooting until we got back. I'll probably have it apart over the weekend to check the internal connections if the wiring looks at all suspect it will get replaced then. Had to do some of that on our previous coach #413.

If that doesn't solve the issue I'll probably pack it up and ship it to Roger Berke for a rebuild.

We are in Texas, but thanks for the offer on the Data Logger.

[folivier]

Richard you replaced the wires inside the burner or the control box?

[Trainer]

Where is Texas are you Steve? I am in the Houston area.

There is no guess the flame sensor is the problem. A quick ohms test give absolute results.

You sure are doing a lot of make work to solve this. My post above will cut to the chase. If one or the other needs bumping, I can diagnose the motor or the box in less than 5 minutes or eliminate them and then go looking for a connection which has a very very small chance of being the cause.

Call me if you wish some assistance. 7 one 3 8 one 8 3234

And I support the Roger Berke rebuild. If you go that route, send the box and burner together. He is the very best.

[Tony Van Helden]

Watching this closely as I currently have the exact same issue going on.