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Bill_Satellite's avatar
Bill_Satellite
Explorer II
Nov 06, 2013

Webasto/Aqua hot

If anyone is familiar with a Webasto diesel furnace, I have one that's acting up. It's the 45-50,000 BTU unit with the 287.962 12V silver control box. I have checked everything I know to check. The hi-limit switch has continuity, the spark sparks, the fuel solenoid clicks with separate 12V power and the blowers and pumps all work. However, the fuel solenoid will not open to allow the unit to fire. I can see that no 12V power is getting to it but am not sure what controls that. What I do know that I believe to be incorrect is that the C6 plug only shows 4.83VDC while all other ports have 12V. Is this an indication that the controller is not good and if so, is that the only way to tell or is there something I can do to test the controller itself before I have to spend $600+ for a new controller?

4 Replies

  • www.hydronicheaterrepair.com is Roger Berke's website. He is the Aqua Hot "guru" and has manuals and troubleshooting info online. HE also sells and ships parts. He is Aqua Hot Certified.
  • Yes, I have the manuals but there's nothing in there that says anything about troubleshooting the controller since the assumption is that you have the dealer module that allows you to test specific things.

    Thanks Twomed, I will see if I can find him on E-Bay. $400 sounds a lot better. I did see one listed as used with a 7-day return option, maybe that's the one.
  • Sounds like you have the trouble tree. If so and it becomes a controller a guy on Ebay rebuilds them...around $400. Old time Bus Nut... I have used his 4 button thermostats for folks, always work.

    Good Luck

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