Error Monitor - Webasto Air Top Evo 3900 Workshop Manual

Air Top Evo 3900/5500
3.3. FL vehicles
3.3.1. The combustion heaters shall be put out of
operation by at least the following methods:
a) intentional manual switching off from the driver's
cab;
b) stopping of the vehicle engine; in this case the
heating device may be restarted manually by the
driver;
c) start-up of a feed pump on the motor vehicle for the
dangerous goods carried.
3.3.2 After running is permitted after the combustion
heaters have been put out of operation.For the
methods set out in points
(b) and (c) of paragraph 3.3.1 the supply of combustion
air shall be interrupted by suitable measures after an
after-running cycle of not more than 40 seconds. Only
heaters for which proof has been furnished that the
heat exchanger is resistant to the reduced after-
running cycle of 40 seconds for the time of their normal
use shall be used.
End of extract.
3.8 Fault lock-out
Errors on the various heater components and faults in the
starting process and in heating mode are identified in the
control unit.The heater is switched off and goes into fault
lock-out if the following conditions occur:
• No or incorrect start
• Temperature sensor defective
• Overheating sensor interrupt or short circuit
• Overheating sensor installed incorrectly
• Glow plug/Flame monitor interrupt or short circuit
• Fan motor overload or blocked or short circuit or
interrupt
• Error in metering pump circuit
• Undervoltage below 10.5 V / 21 V for longer than 20
seconds
• Overvoltage above 16 V / 32 V for longer than 6
seconds
• Control unit defective
• Overheating
3 Function description
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 it stops the control unit will be set to fault lock-out.
The 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).

3.8.1 Error monitor

The overheat, incorrect start and flame failure errors are
counted and cause the heater to suffer a fault lock-out
after an error has occurred the maximum number of times.
The incorrect start counter FSZ is incremented by 1 each
time the heater fails to start. If the incorrect start counter
reaches its maximum value of 9 the heater will go into the
heater lock-out status HGV.
The error counter SZ is incremented by 1 each error for
which there is no separate counter. If the error counter
reaches its maximum value of 5 the heater will go into the
heater lock-out status HGV.
The overheating counter ÜHZ is incremented by 1 each
time the heater overheats. If the overheating counter
reaches its maximum value of 5 the heater will go into the
heater lock-out status HGV.
After a flame abort FAZ, a restart is automatically carried
out. The condition for a restart is that the heater unit was
in the control mode directly beforehand. During the restart
the cycle repetition counter ZWZ is increased by one. This
process is repeated until the heater unit either burns
properly again or the maximum value of 3 for the cycle
repetition counter has been reached.
The flame abort counter FAZ is increased by 1 when the
cycle repetition counter ZWZ has reached the maximum
value. If the flame abort counter reaches its maximum
value of 3 the heater will go into the heater lock-out status.
Automatic reset:
Following each heater unit start-up, the cycle repetition
counter ZWZ is set to 0. The fault counter is set to 0 after
a fault-free transition to the control mode and the flame
abort counter FAZ, overheating counter UHZ and false
starting counter FSZ are set to 0 after(!) fault-free
combustion operation (6 min.).
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