48
Installation and maintenance instructions Compact 0020313973_01
Code/meaning
Possible cause
Measure
F.22
System pressure too low
Cable for the pump/for the wa-
ter pressure sensor is loose/not
connected/defective
▶
Check the cable for the pump/for the water pressure sensor.
F.23
Safety switch-off: Temperature
difference too great
Pump blocked
▶
Check that the pump is working correctly.
Air in the product
▶
Purge the heating installation.
Pump runs with insufficient out-
put
▶
Check that the pump is working correctly.
Flow and return temperature
sensor connection inverted
▶
Check the connection for the flow and return temperature
sensor.
F.24
Safety switch-off: Temp. incr.
too fast
Pump blocked
▶
Check that the pump is working correctly.
Pump runs with insufficient out-
put
▶
Check that the pump is working correctly.
Air in the product
▶
Purge the heating installation.
System pressure too low
▶
Check the system pressure.
Non-return valve blocked
▶
Check that the non-return valve is working correctly.
Non-return valve installed incor-
rectly
▶
Check the installation location of the non-return valve.
F.25
Safety shutdown: Flue gas tem-
perature too high
Flue gas safety cut-out plug is
not plugged in or is loose
▶
Check the plug and the plug connection.
Interruption in the cable harness
▶
Check the cable harness.
F.27
Safety switch-off: Flame simula-
tion
Moisture on the PCB
▶
Check that the PCB works correctly.
PCB defective
▶
Replace the PCB.
Gas solenoid valve not leak-
tight
▶
Check that the gas solenoid valve works correctly.
F.28
Ignition unsuccessful
Gas isolator cock closed
▶
Open the gas isolator cock.
Gas meter defective
▶
Replace the gas meter.
The gas pressure monitor has
been triggered
▶
Check the gas flow pressure.
Air in the gas supply (e.g. dur-
ing initial start-up)
▶
Reset the unit once.
Gas flow pressure too low
▶
Check the gas flow pressure.
The thermal isolator device has
been triggered
▶
Check the thermal isolator device.
Condensate discharge pipe
blocked
▶
Check the condensate discharge pipe.
Incorrect replacement gas valve
assembly
▶
Check the replacement gas valve assembly.
Incorrect gas valve assembly
offset
▶
Check the offset setting for the gas valve assembly.
Gas valve assembly defective
▶
Check the gas valve assembly.
Multiple plug loose/not plugged
in
▶
Check the multiple plug and plug connection.
Interruption in the cable harness
▶
Check the cable harness.
Ignition system defective
▶
Replace the ignition system.
Earthing defective
▶
Check the product's earthing.
Electronics defective
▶
Check the PCB.
Air/flue pipe blocked
▶
Check the air/flue pipe.
Restrictor for the reference
pressure pipe blocked
▶
Check the condition of the restrictor on the gas valve
assembly's reference pressure pipes.
F.29
Ignition and check faults during
operation
–
flame has gone out
The gas supply is interrupted
▶
Check the gas supply.
Incorrect flue gas recirculation
▶
Check the flue gas recirculation.
Earthing defective
▶
Check the product's earthing.
Ignition misfire
▶
Check that the ignition transformer works correctly.
Condensate discharge pipe
blocked
▶
Check the condensate discharge pipe.
Air/flue pipe blocked
▶
Check the air/flue pipe.
Summary of Contents for Compact 24c-AS/1
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