Webasto air heater not starting

[chrisdaykin]

I have a Webasto Air Top 2000S as fitted new to our 2007 Bavaria 30. It has become increasingly tricky to fire up, with the 3 long flash error code often being displayed (indicating over or under voltage I think).  Last year it usually started OK if the engine (D1-20) was running.  I replaced the service battery (it needed replacing anyway) last year but sadly made no difference. This year, even with the engine running, it is now impossible to fire up, always displaying the 3 long flashes about 20-30 secs into the start-up routine.  I spoke to the Webasto rep at the Boat Show this week and he suggested that I clean up all the input electrical connections (at battery and fuse-holder) - they were a bit rusty, but after a good clean/sanding down of the connectors, the same symptoms persist.   UK temperatures are dropping now, so any ideas gratefully received!

[elias]

I had the same issues in the past with a Chinese replica . Have in mind that it draws lots of amp on the start up . Are your cables thick
Enough ? Maybe the run a lot of meters and due to small size you have a great voltage drop ? Can you use a voltometer to check while starting it ?

Another thing that happened to me , is because of water from condensations trapped in the exhaust system . Do you have a drain valve for it to empty it ? Does it produces lots of smoke ?

[tiger79]

Take it out of the boat and take it to a Webasto service agent.  It will probably need a new combustion screen.  Mine needs this doing about every 4 years.

[SYJetzt]

I would bet on a bad cabling! As Elias suggested, i would measure between the white and red cable on the operating panel, if there is the voltage higher than 10Volts when the heater is firing up. Use  sharp probes to pierce into the two lines. If not, try to dismantle the cabling plugs on the heater itself an clean them diligent and apply some contact spray.