The high temperature fuse kept failing after replacing a Marathon Coach installed Webasto system solenoid valve an losing coolant ...this is my procedure on how to bleed the system to restore operation.
I have arctic version of the Webasto model DBW2010.74 in Marathon Coach #1085, 2008 Marathon, 2006/7 Prevost chassis. The Webasto suddenly quit heating a few days ago and started to drip raw fuel out the exhaust pipe. I am third owner of coach...in checking the heater, it is obvious it has never been maintained. It tries to light off and does a puff-puff-puff for a while but finally quits trying, only the motor continues to run. The ignition is sparking. Likely the nozzle is corrupted. The heater worked great when it was operable. Any ideas to try first?
Have it serviced by Marathon or Prevost. There are only a few thiings that could be wrong. The spacing of your ignitor tips is one. A dirty nozzle another. If its clicking it's getting spark.