Dirty fuel
I found that my heater ceased after one long winter of use. Before this there was a lot of black smoke from the exhaust, and it would taker a number of turns on the controller to ignite the burner. We stripped the burner down on a pontoon and found it was completely choked with soot. Apparently the quality of diesel fuel supplied in the UK is considerably poorer than in Germany, and the poor heater soots up badly if used a great deal. The trick was cleaning, and then very carefully resassembling(!) Now after consulting Webasto, we turn the heater on full power for a couple of hours regularly even during the summer months to 'burn off' any soot. What they hate is constant use on a 'low setting'.
