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Webasto Product N.A., Inc.
Air Top Evo 3900/5500
Fault Lock-out
13. Fault Lock-out
The control unit continuously monitors the heater operation. The control unit identifies errors on individual heater
components and faults during operation. Should the control unit experience component errors and operational faults,
the heater will be shut down.
The heater is shut down (fault lock-out) if:
– No or incorrect start
– Temperature sensor defective
– Overheating sensor interrupt or short circuit
– Overheating sensor installed incorrectly
– Ceramic glow pin interrupt or short circuit
– Fan motor overload or blocked or short circuit or interrupt
– Error in the fuel metering pump or overheating guard circuit (start phase only)
– Under voltage less than 10 V or over voltage greater than 15 V and for longer than 20 seconds (on 12 V heater)
– Under voltage less than 20 V or over voltage greater than 32 V and for longer than 20 seconds (on 24 V heater)
– Control unit defective
– Overheating
The fuel supply is stopped if the heater overheats.
The heater continues to run in the same way as if it is switched off manually.
After the heater stops the control unit will be set to fault lock-out.
Overheating is indicated by the indicator flashing 10 times.
Rectify the cause of the fault.
To reset the fault, switch the heater on and off briefly (at least 2 seconds).
If serious faults, such as overheating or no start, occur frequently, the heater will be set to fault lock-out (F 12) and can
be restarted by disconnecting the supply voltage (e.g. removing the fuse).
13.1 Error Code Output
NOTE:
An error code is generated on the control element indicator light after an error has occurred. When determining the
generated code, there will be a series of 5 fast flashes after which, the error code will be generated by a sequence of
long flash pulses, count only the long flash pulses to obtain the code. Error codes are shown in the table below.
If the heater is fitted with a combination timer, an error message will appear on the display of the timer after a fault
occurs. If the control element is used, the error number is indicated by the indicator light flashing:
F 00
Control unit error / incorrect parameter set / warm start recognition
F 01
No start (after 2 attempts to start) / no flame formation
F 02
Flame failure (repeated more than 3 times)
F 03
Under voltage or over voltage
F 04
Premature flame recognition
F 06
Temperature sensor interrupt or short circuit
F 07
Metering pump interrupt or pump short circuit
F 08
Fan motor interrupt or short circuit or overload or blocked
F 09
Ceramic glow pin interrupt or short circuit
F 10
Overheating: Resulting in permanent heater fault lock-out
F 11
Overheating sensor interrupt or short circuit
F 12
Heater lock-out
F 13
Heater lock-out permanent
F 14
Overheating sensor incorrect position
F 15
Set point generator interrupt