Vaillant ecoTEC plus VU 446/5-5 (H-GB) Installation And Maintenance Instructions Manual page 62

Code/meaning
F.61
Gas safety valve drive fault
F.62
Gas safety valve connection
fault
F.63
Fault: EEPROM
F.64
Fault: Electronics/NTC
F.65
Electronics temperature fault
F.67
Flame plausibility fault
F.70
Invalid device specific number
(DSN)
F.71
Flow temperature sensor fault
F.72
Flow and/or return temperature
sensor fault
F.73
Water pressure sensor signal in
the wrong range (too low)
F.74
Water pressure sensor signal
outside correct range (too high)
F.75
Pump fault/water deficiency
62
Possible cause
Short circuit in the cable har-
ness
Gas valve assembly defective
PCB defective
PCB defective
The connection to the gas valve
assembly has been interrup-
ted/broken
PCB defective
Flow NTC short circuit.
Return NTC short circuit
PCB defective
Electronics overheated
PCB defective
PCB defective
Device Specific Number not
set/is incorrect
Output range coding resistor
missing or is incorrect
The flow NTC reports a con-
stant value
Incorrect position of the flow
NTC
Flow NTC defective
Flow NTC defective
Return NTC defective
Short circuit in the cable har-
ness
Interruption in the cable harness
Water pressure sensor defect-
ive
Short circuit in the cable har-
ness
Interruption in the cable harness
Water pressure sensor defect-
ive
Malfunction
D.149 = 1, pump blocked alarm
D.149 = 2, electrical pump fault
alarm
D.149 = 3, pump dry running
alarm
D.149 = 5, no pressure peak
detection
Measure
▶
Check the cable harness.
▶
Replace the gas valve assembly.
▶
Replace the PCB.
▶
Replace the PCB.
▶
Check the connection to the gas valve assembly.
▶
Replace the PCB.
▶
Check that the flow NTC works correctly.
▶
Check that the return NTC works correctly.
▶
Replace the PCB.
▶
Check the external heat effects on the electronics.
▶
Replace the PCB and the ionisation electrode.
▶
Replace the PCB.
▶
Set the correct Device Specific Number.
▶
Check the output range coding resistor.
▶
Check the positioning of the flow NTC.
▶
Check the positioning of the flow NTC.
▶
Replace the flow NTC.
▶
Replace the flow NTC.
▶
Replace the return NTC.
▶
Check the cable harness.
▶
Check the cable harness.
▶
Replace the water pressure sensor.
▶
Check the cable harness.
▶
Check the cable harness.
▶
Replace the water pressure sensor.
▶
Call up diagnostics code D.149 to obtain further information
about the malfunction.
Overview of diagnostics codes (Validity: VU 446/5-5 (H-GB)
OR VU 606/5-5 (H-GB)) (→ Page 55)
1. Remove the blockage from the pump.
2. Replace the pump.
1. Check the pump's supply voltage.
2. Replace the pump.
1. Check the pressure of the hydraulic circuit; ensure that there
is no air in the circuit.
2. Replace the pump.
1. Check the system pressure.
2. Purge the heating installation (purge programme).
3. Check the water pressure sensor.
4. Replace the water pressure sensor.
Installation and maintenance instructions ecoTEC plus 0020261389_03