Valeo Thermo H 160, Workshop Manual

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Thermo H plus 4 Functions of the heater
4.6.4 Fault lock-out release and error clearance
The fault lock-out is released when the heater is switched
off.
After that it will be immediately ready for operation.
The detected error is stored in the error memory and can
be read using DTT diagnosis. It is possible to delete the
stored error using the DTT diagnosis
4.7 Heater lock-out
The heater lock-out overrides the standard fault lock-
out.
If the heater lock-out is active, neither start nor purge
cycle are executed after switching the heater back on.
Prior to restarting the heater troubleshooting must be
performed by personnel trained by Valeo in order to iden -
tify the root cause.
After that the heater interlock can be released (see 4.7.1 ).
NOTE:
If malfunctions occur during switching-on or during the
start process prior to ignition, the heater will be switched
off without purge cycle.
The heater is in the heater lock-out.
The burner motor stops immediately or does not start.
Besides that a purge cycle between 30 seconds and 60
seconds is performed depending on error type and timing.
Subsequently the heater status is switched to heater lock-
out.
If the circulating pump is externally actuated it will con-
tinue operating, if it is not affected itself.
Heater lock-out causes:
• Short circuit and/or interruption of electrical compo -
nents:
– Solenoid valve
– Flameguard
– Overheating protection
– the temperature sensor (overheat protection/water
temperature sensor) is unplugged.
• Flame is not expired within 30 seconds after purge
cycle (burner motor stops).
• Overheating protection triggered.
• Control device error
• Repeated malfunctions
• Repeated flame interruptions
4.7.1 Heater lock-out release
To release, the switched on heater must be disconnected
from the vehicle electrical system as follows.
4.7.1.1 Release a heater lock-out without DTT
diagnosis
NOTE:
Disconnect the power supply for release, by pulling the
plug C is not permissible.
1. Remedy the cause of the heater lock-out.
2. Disconnect the power supply (e.g. by pulling the fuse)
for at least 10s.
3. Reconnect power supply.
4. Switch the locked-out heater off and then on again.
5. Repeat steps 2. and 3.
6. Heater is ready for service and starts, if necessary
turn it off.
NOTE:
If the main switch remains in the on position when discon-
necting the power supply, the heater automatically starts
after connecting it to the vehicle electrical system.
The heater can be switched off during initial cycle.
4.7.1.2 Release the heater lock-out using the DTT
diagnosis
1. Connect the heater with the DTT diagnosis and read
out the error memory.
2. Remedy the cause of the heater lock-out.
3. Disconnect the power supply (e.g. by pulling the fuse)
for at least 10s.
4. Reconnect the heater to the vehicle electrical system.
5. Using the DTT diagnosis, delete the error/error
memory.