D Overview Of Fault Codes - Vaillant home combi Installation And Maintenance Instructions Manual

Status code
S.17 DHW mode: Pump overrun
Display in Comfort mode with warm start or hot water handling mode with cylinder
S.20 Hot water handling mode: Requirement
S.21 Hot water handling mode: Advance fan operation
S.22 Hot water handling mode: Pump pre-run
S.23 Hot water handling mode: Burner ignition
S.24 DHW mode: Burner on
S.25 DHW mode: Pump/fan overrun
S.26 DHW mode: Fan overrun
S.27 DHW mode: Pump overrun
S.28 Hot water handling mode: Temporary shutdown of the burner
S.30 Room thermostat is blocking heating mode.
S.31 No heating demand: Summer mode, eBUS controller, waiting period
S.32 Fan waiting time: Fan speed outside of the tolerance values
S.33 Forced fan operation until the pressure monitor is switched
S.34 Frost protection active
S.39 Underfloor heating contact open
S.41 Water pressure too high
S.42 Flue non-return flap closed
S.46 Protection mode: Minimum load
S.53 Product in waiting period/operation block function due to low water pressure (flow/return spread too large)
S.54 Waiting period: Low water pressure in the circuit (flow/return spread too large)
S.88 Product purging active
S.91 Maintenance: Demo mode
S.96 Automatic test programme: Return temperature sensor, heating and hot water request blocked.
S.97 Automatic test programme: Water pressure sensor, heating and hot water request blocked.
S.98 Automatic test programme: Return temperature sensor, heating and hot water request blocked.
S.99 Automatic filling active
S.108 Purging the combustion chamber, fan in operation
S.109 Product's standby mode activated
D Overview of fault codes
Note
Since the code table is used for various products, some codes may not be visible for the product in question.
Fault code Meaning
F.00 Fault: Flow temperature sensor
F.01 Fault: Return temperature sensor
F.10 Short circuit: Flow temperature sensor
F.11 Short circuit: Return temperature sensor
F.13 Short circuit: Domestic hot water cylinder
temperature sensor
F.20 Safety switch-off: Overheating temperat-
ure reached
0020224355_00 HOME Installation and maintenance instructions
Meaning
Other displays
Possible cause
NTC plug not plugged in or has come loose, multiple plug on the PCB not
plugged in correctly, interruption in cable harness, NTC sensor defective
NTC plug not plugged in or has come loose, multiple plug on the PCB not
plugged in correctly, interruption in cable harness, NTC sensor defective
NTC sensor defective, short circuit in the cable harness, cable/casing
NTC sensor defective, short circuit in the cable harness, cable/casing
NTC sensor defective, short circuit in the cable harness, cable/casing
Incorrect earth connection between cable harness and product, flow or return
NTC defective (loose connection), black discharge via ignition cable, ignition
plug or ignition electrode
Appendix
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