Webasto Air Top Evo 3900 Operating Instructions Manual - Cause Remedy
If an error occurs, first check the fuse and plug connections to ensure that they are in proper
condition and connected correctly.
If the actions described below do not rectify the error, have the heater checked by Webasto-
trained personnel.
Cause Remedy
No combustion after
start and repeat start
Switch heater unit off (for at least 2 seconds) and then
on again
Flame extinguishes during
operation
Switch heater unit off (for at least 2 seconds) and then
on again
Heater unit overheats and
indicator flashes
Make sure that hot air can flow freely, allow heater unit
to cool down, Switch heater unit off (for at least 2
seconds) and then on again
Vehicle voltage too low
Charge battery
Switch heater unit off (for at least 2 seconds) and then
on again
Cause Remedy
Combustion air and/or exhaust
system blocked
Check combustion air and exhaust system for blockage
Actions in event of faults
Heater unit cuts out automatically
Heater unit emits black smoke