Vaillant auroCOMPACT VSC S/4 Series Installation And Maintenance Instructions Manual page 54

Appendix
Code Meaning
F.74 Water pressure sensor signal outside correct
range (too high)
F.75 Fault: Insufficient throughput on pump start-up.
F.77 Fault: Flue non-return flap/condensate pump
F.81 Cylinder charging pump fault
F.82 Impressed current anode fault (if installed as an
accessory)
F.83 Fault: Flow and/or return temperature sensor
temperature change
F.84 Fault: Flow/return temperature sensor temperat-
ure difference implausible
F.85 Fault: Flow and return temperature sensors
incorrectly installed
F.86 Fault: Floor contact
F.90 Fault: No communication between SMU and
BMU
F.92 Coding resistance fault
F.93 Gas group fault
Commu- No communication with the PCB
nication
fault
F.1018 Solar pump control system fault
F.1020 Safety switch-off: Temperature limiter
F.1021 Solar pump running dry
F.1070 SMU configuration error
F.1273 Solar pump electronics fault
F.1276 Solar pump blocked
F.1278 Panel sensor fault
F.1279 Fault in sensor on lower part of cylinder
F.1355 Mass flow sensor fault
54
Cause
Line to water pressure sensor has a short circuit to 5 V/24 V or internal
fault in the water pressure sensor
Pump defective, air in heating installation, too little water in unit, mass
flow sensor defective
No response from flue non-return flap or condensate pump defective
Air in heating and hot water circuit, charging pump malfunction
Connection of anode or PCB of impressed current anode defective
When the burner starts, the temperature change registered at the flow
and/or return temperature sensor is non-existent or too small
–
Insufficient water in product
–
Flow or return temperature sensor not in correct position at pipe
Flow and return temperature sensors returning implausible values.
–
Flow and return temperature sensors have been inverted
–
Flow and return temperature sensors have not been correctly in-
stalled
The flow and/or return temperature sensors have been installed on the
same pipe/incorrect pipe
Activate the overheating thermostat for the underfloor heating: Set the
heating target value
Interruption between BMU and SMU, faulty product code
The coding resistance on the PCB does not match the entered gas
group: Check the resistance, repeat the gas family check and enter the
correct gas group.
Combustion quality outside the permitted range: Incorrect gas restrictor,
recirculation, incorrect gas group, internal pressure measuring point in
Venturi blocked (do not use lubricant on the O-ring in the Venturi).
Communication fault between display and PCB in the electronics box
Pump control cable harness disconnected.
Solar cylinder temperature too high
Lack of solar fluid in solar circuit.
Incorrect coding resistance identified
Connection fault, fault in pump PCB
Solar pump defective
Sensor incorrectly connected or defective
Sensor incorrectly connected or defective
Flow sensor defective or not connected, power supply or PWM control
system of solar system not connected, solar valve (blue or red) closed,
air in solar circuit, pressure in solar circuit too low.
Installation and maintenance instructions auroCOMPACT 0020181589_04