Vaillant ecoTEC plus VU 446/5-5 (H-GB) Installation And Maintenance Instructions Manual page 48

Appendix
Message
F.33 Air pressure switch fault
F.49 Fault: eBUS
F.61 Gas safety valve drive
fault
F.62 Gas safety valve connec-
tion 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 temper-
ature 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 defi-
ciency
48
Possible cause
PCB defective
Excessive counter-pressure in
the air/flue pipe
eBUS overload
Short circuit in the eBUS con-
nection
Different polarities at the eBUS
connection
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
Measure
▶
Replace the PCB.
1. Ensure that there is no risk of excessive counter-pressure.
2. If required, protect the product (wind guard, cascade lines
with a larger diameter, etc.).
▶
Check that the eBUS connection works correctly.
▶
Check that the eBUS connection works correctly.
▶
Check that the eBUS connection works correctly.
▶
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 (Applicability: VU 446/5-5 (H-
GB) OR VU 606/5-5 (H-GB)) (→ Page 42)
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.
Installation and maintenance instructions ecoTEC plus 0020261389_02