12
5.3 Purpose, Dismounting, and Replacement of the Flame Detector
Continued
Method 2.
Remove the FD from the housing and
measure the voltage at outputs of the
FD that is being heated up. When the
FD housing is heated up to +100°С
(boiling water temperature), its outputs
must provide voltage at about 3 mV.
The positive pole is marked with a red
tube and the negative with a black one.
In case of an open circuit, the FD
must be deemed faulty and should
be replaced.
To check the FD channel of the control
unit, install a jumper in place of the FD
(Fig. 6a). Connect the control unit sock-
ets to the harness. If a malfunction code
related to the FD (malfunction code 5)
does not appear after the pre-heater
launch, the CU is fault-free. Remove the
jumper and connect a fault-free FD.
Replace the FD in the reverse order.
Where the fault persists, check the
polarity of the FD connection (the wire
with a black mark must be connected
with the CU connector marked with a
black dot, as shown in Fig. 6b). An error
in the placement of the marking on the
FD wires is also possible. To remedy this
situation, swap the FD terminals in the
control unit socket.
Fig. 6a.
Jumper
Fig. 6b.
FD to CU connection
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