405
Thermo H plus
4 Functions of the heater
4.5
Fault lock-out and heater lock-out
A distinction is made between fault lock-out and heater
lock-out.
The lock-outs protect the heater and the surrounding
vehicle assemblies against sequence errors after a failure
or a malfunction of individual heater components.
In a heater lock-out safety-related components are
affected by the failure or malfunction. It may only be
released by Valeo trained personnel after eliminating the
cause.
Each fault lock-out and heater lock-out is stored in the
control device.
4.6
Fault lock-out
If one of the malfunctions listed below occurs, the heater
will initiate a fault shut-down, followed by a fault lock-out.
Depending on the error timing, no purge cycle or a 120
seconds purge cycle will be executed.
Flash impulses are outputted via the operation indicator.
In case of several sequential fault lock-outs a heater lock-
out is initiated.
NOTE:
If the circulating pump is externally actuated it will con-
tinue operating, if it is not affected itself.
In case of several sequential fault lock-outs a heater lock-
).
4.6.1 Malfunctions during switching-on and
start procedure
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 fault lock-out.The motor stops immedi
-
ately or does not start.
Malfunction criteria:
• Short circuit and/or interruption of electrical compo
-
nents:
– Circulating pump
– Electronic ignition unit
– Optional nozzle block preheater
• Flame or extraneous light detection by the flameguard
prior to opening of the solenoid valve.
• No start: No flame detection within 15 seconds after
opening the solenoid valve.
• Temperature sensor delivers unacceptable tempera
-
ture values.
• Burner motor speed signal faulty.
• Voltage falls short of the low voltage threshold of
approx. 20.5 V within a duration of 20 seconds after a
heating request.
• Voltage exceeds the high voltage threshold of approx.
30 V within a duration of 6 seconds (purge cycle only,
no fault lock-out).
4.6.2 Malfunctions during heater operation
In case of malfunctions during heater operation, a 120
seconds purge cycle will be executed first. Subsequently
the heater status is switched to fault lock-out.
Malfunction criteria:
• Circulating pump - short circuit and/or interruption
• Water temperature greater than the upper switching
threshold
• Temperature sensor delivers unacceptable tempe-
rature values.
• Heater operation outside the permissible temperature
range.
• Burner motor speed signal faulty.
• Flame interruption (combustion interruption for longer
than 15 seconds).
• Voltage falls short of the low voltage threshold of
approx. 20.5 V within a duration of 20 seconds after a
heating request.
• Voltage exceeds the high voltage threshold of approx.
30 V within a duration of 6 seconds (purge cycle is
applied only, but no fault lock-out).
• Control device malfunction
4.6.3 Malfunctions during purge cycle
After the purge cycle the heater goes into the fault lock-
out.
Malfunction criteria:
• Circulating pump - short circuit and/or interruption
• Heater operation outside the permissible temperature
range.
• Burner motor speed signal faulty.
• Voltage falls short of the low voltage threshold of
approx. 20.5 V within a duration of 20 seconds after a
heating request.
• Voltage exceeds the high voltage threshold of approx.
30 V within a duration of 6 seconds (purge cycle is
applied only, but no fault lock-out).
• Control device malfunction
Summary of Contents for Thermo H 160
Page 47: ...memos...
