Webasto Air Top Evo 3900 Operating Instructions Manual - page 10
If the system is fitted with a combination timer, when an error occurs an error code is
output on the timer's display until the heater has been rectified.
The error code is output if the heater is fitted with a control element after an error has
occurred by the switch-on indicator/error code indicator flashing. After a burst of fast
flashes the error code will be output by a sequence of long flashes, the number of which
is shown in the table below.
If serious faults, such as overheating or no start, occur frequently, the heater will be set to
permanent fault lock-out (F 12) and cannot be restarted until it has been repaired by
Webasto-trained personnel.
Error code
Meaning
F 00
Control unit error
F 01
No start (after 2 starting attempts)
F 02
Flame failure (at least > 3)
F 03
Undervoltage or overvoltage
F 04
Premature flame recognition
F 06
Temperature sensor interrupt or
temperature sensor short circuit
F 07
Metering pump interrupt or metering pump
short circuit
F 08
Fan motor interrupt or
fan motor short circuit or
fan motor overload or blocked
F 09
Glow plug interrupt or
glow plug short circuit
F 10
Overheating
F 11
Overheating sensor interrupt or
overheating sensor short circuit
F 12
Heater unit lock-out
F 14
Overheating sensor installed incorrectly
F 15
Setpoint generator short circuit
Error code output on combination timer or control element