Vaillant ecoTEC plus VU GB 5-5 Series Installation And Maintenance Instructions Manual page 44

Appendix
Code Meaning
F.32 Fan fault
F.34 Safety shutdown: Pressure monitoring
F.35 Fault: Air/flue pipe
F.49 Fault: eBUS
F.61 Fault: Gas valve assembly actuation
F.62 Fault: Gas valve assembly switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Unstable flame signal
F.70 Invalid device specific number (DSN)
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 Fault: No pressure change detection when start-
ing pump
F.76 Overheating protection on primary heat ex-
changer has responded
F.77 Fault: Flue non-return flap/condensate pump
Commu- No communication with the PCB
nication
fault
F.83 Fault: Flow and/or return temperature sensor
temperature change
F.84 Fault: Flow/return temperature sensor temperat-
ure difference implausible
44
Cause
Plug on fan not correctly plugged in, multiple plug on PCB not correctly
plugged in, break in cable harness, fan blocked, Hall sensor defective,
electronics defective
Flue pressure switch: Cable break, blocked flue gas route Water pres-
sure switch: Hydraulic leakage, air in the heating circuit
Air/flue pipe blocked
Short circuit on eBUS, eBUS overload or two power supplies with differ-
ent polarities on the eBUS
–
Short circuit/short to earth in cable harness for the gas valve as-
sembly
–
Gas valve assembly defective (coils shorted to earth)
–
Electronics defective
–
Delayed shutdown of gas valve assembly
–
Delayed extinguishing of flame signal
–
Gas valve assembly leaking
–
Electronics defective
Electronics defective
Flow or return NTC short circuited, electronics defective
Electronics overheating due to external influences, electronics defective
Implausible flame signal, electronics defective
Air in gas, gas flow pressure too low, incorrect air ratio, condensate
route blocked, incorrect gas injector, ionisation flow interruption (cable,
electrode), flue gas recirculation, condensate route
If spare parts were integrated: Display and PCB replaced at the same
time and Device Specific Number not reset; incorrect cable harness;
liquefied petroleum gas coding resistor and DSN do not match
Interruption/short circuit of water pressure sensor, interruption/short
circuit to GND in supply line to water pressure sensor or water pressure
sensor defective
Line to water pressure sensor has a short circuit to 5 V/24 V or internal
fault in the water pressure sensor
Water pressure sensor and/or pump defective, air in the heating installa-
tion, insufficient water in the product; check adjustable bypass, connect
external expansion vessel to the return
Cable or cable connections for safety fuse in primary heat exchanger or
primary heat exchanger defective
No response from flue non-return flap or condensate pump defective
Communication fault between display and PCB in the electronics box
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/return temperature sensor not installed correctly
Flow/return temperature sensors returning implausible values
–
Flow/return temperature sensor not installed correctly
Installation and maintenance instructions ecoTEC plus 0020134823_07