Vaillant uniTOWER plus - H Maintenance Messages; I Comfort Protection Mode; J Fault Codes

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56 Installation and maintenance instructions 0020291525_04
H Maintenance messages
Code Meaning Cause
Remedy
M.23 Status external current anode – External current anode not recog-
nised
– If required, check for a cable break
M.32 Building circuit: Waterpress. Low – Pressure loss in the building circuit
due to leakages or air pockets
– Building circuit pressure sensor is
defective
– Check the building circuit for leaks,
top up with heating water and purge
– Check the plug contact on the PCB
and on the wiring harness; check
that the pressure sensor is working
correctly and, if required, replace the
pressure sensor
M.200 Building circuit : Brine pressure
low
– Pressure loss in the building circuit
due to leakages or air pockets
– Building circuit pressure sensor is
defective
– Check the building circuit for leaks,
top up with heating water and purge
– Check the plug contact on the PCB
and on the wiring harness; check
that the pressure sensor is working
correctly and, if required, replace the
pressure sensor
M.201 Sensor fault: Cylinder temperature – Cylinder temperature sensor defect-
ive
– Check the plug contact on the PCB
and on the wiring harness; check
that the sensor is working correctly
and, if required, replace the sensor
M.202 Sensor fault: System temperature – System temperature sensor defective – Check the plug contact on the PCB
and on the wiring harness; check
that the sensor is working correctly
and, if required, replace the sensor
M.203 Connection fault: Disp. not recog-
nised
–
Display defective
– Display not connected
–
Check the quality of the plug contact
on the PCB and on the wiring har-
ness
– Replace the display, if required
I Comfort protection mode
Code Meaning Description Remedy
200 Sensor fault: Temp. air inlet Still possible to operate with existing,
functional outdoor temperature sensor
Replace the air inlet sensor
J Fault codes
Code Meaning Cause
Remedy
F.022 Building circuit: Water press. too
low
– Pressure loss in the building circuit
due to leakages or air pockets
– Building circuit pressure sensor
defective
– Check the building circuit for leaks
– Top up with water, purge
– Check the quality of the plug contact
on the PCB and on the wiring har-
ness
– Check that the pressure sensor is
working correctly
– Replace the pressure sensor
F.042 Fault: Coding resistor – Coding resistor damaged or not set – Check that the coding resistor is
positioned correctly and, if required,
replace it.
F.073 Sensor fault: Building circ. water
pressure
– The sensor is not connected or the
sensor input has short-circuited
– Check and, if required, replace the
sensor
– Replace the wiring harness
F.094 Fault: Vortex – Volume flow sensor not connected or
sensor input has short-circuited
– Check and, if required, replace the
sensor
– Replace the wiring harness
F.103 Fault: Spare part ident. – Incorrect control PCB installed on
the outdoor unit
– Installing the correct PCB
F.514 Sensor fault: Compr. inlet temp.
– The sensor is not connected or the
sensor input has short-circuited
– Check and, if required, replace the
sensor
– Replace the wiring harness