2020 Vaillant Boiler Fault Codes

Welcome to our 2020 Vaillant boiler fault codes page. If you have arrived here because your boiler is broken and are in need of a licensed heating engineer in the London. Please feel free to contact us here or by using the green Click to Call button below.

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Below you will find a complete list of the most common Vaillant boilers with their corresponding fault codes. Please do note this is only a guide to assist heating engineers in fault diagnosis, however, homeowners are free to use the information below for their own knowledge.

Under no circumstances, do we promote anyone to carry out any work on any gas or oil-fired appliance unless they are either Gas Safe registered and/or OFTEC registered and suitably competent and qualified to do so. We accept no responsibility for the use of this information.

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Vaillant Turbomax 824E / 828E / 837E Combination Boilers Fault Codes

Vaillant Turbomax 615/2 E / 620/2 E / 624/2 E / 628/2 E / 637 E System Boilers Fault Codes


Fault Codes	Meaning	Possible Cause
F.00	Flow-NTC: NTC broken; NTC cable broken; Defective connection at NTC Defective connection at electronics	Flow-NTC cable defective/ broken NTC faulty
F.01	Return NTC: NTC broken; NTC cable broken; Defective connection at NTC Defective connection at electronics	Return-NTC cable defective/broken NTC faulty
F.10	Short circuit - flow-NTC (<130°C)	NTC-plug shorted to casing, NTC defective
F.11	Short circuit - return-NTC (<130°C)	NTC-plug shorted to casing, NTC defective
F.13	—	—
F.20	Over heat cut off activated	Maximun temperature exeeded
F.22	Dry fire / Low water in system / Overheat	This means that there’s either no water in your system, you have a defective pump or the pump lead is defective
F.24	Low water / Pump Failure / Blockage (temperature gradient of flow NTC too steep)	Pump could be obstructed, running at low capacity, could be air trapped or the pressure might be too low.
F.28	Either insufficient gas in the system, a defective electrode, ignition lead or electronic ignitor	No gas; Isufficient gas; Incorrect gas valve adjustment; Electrode defective; Ignition lead defect; Electronic igniter defective
F.29	The flame extinguished re-ignition unsuccessful	Flame or pilot light has gone out – check flue duct or gas supply.
F.32 (837/637 Only)	Main heat exchanger anti-freeze protection mode due to fan speed deviation too great.	Check fan control cables/connections; Defective fan control cable;
F.33 (837/637 Only)	Main heat exchanger anti-freeze protection mode due to no switching signal from the air pressure switch.	Check air pressure switch, fan, fan supply or flue system.
F.37 defect (837/637 Only)	The rotary speed of the fan is too high or too low	Air pressure switch defect; fan defect; electronics
F.41 (837/637 Only)	No setting for the type of gas is stored	Set gas type in PCB (see page 30 manufactures instructions)
F.42	Faulty cable loom	Faulty or incorrect loom fitted
F.43	Faulty cable loom	Faulty or incorrect loom fitted
F.60	Gas valve control defective	Wiring loom (connects gas valve) might have short-circuited, gas valve assembly defective or electronic control system issue.
F.61	Gas valve control defective	Wiring loom (connects gas valve) might have short-circuited, gas valve assembly defective or electronic control system issue.
F.62	Flame rectification present 4 secs. after gas valve turns off. Defective gas valve closure mechanism	Check gas valve, burner tubes and injectors or electronics defect
F.63	EEPROM (Electrically Erasable Programmable Read-Only Memory) error	EMC or Electronic fault.
F.64	Electronic system or sensor fault	Flow or backflow NTC has short-circuited, or an electronic fault
F.65	Electronic system temperature too high	This can happen because of an external heat source or an electrical fault
F.67	Electronic fault in the flame system	Electronics defect

Vaillant ecoTEC Plus 831 / 824 / ecoTEC Pro 28 Combination Boilers Fault Codes

Vaillant ecoTEC Plus 612 / 615 / 618 / 624 / 630 System Boilers Fault Codes

ecoTEC pro 28 GC 28 47-044-30

ecoTEC plus 824 GC 47-044-31

ecoTEC plus 831 GC 47-044-32

ecoTEC plus 612 GC 41-044-44

ecoTEC plus 615 GC 41-044-45

ecoTEC plus 618 GC 41-044-46

ecoTEC plus 624 GC 41-044-47

ecoTEC plus 630 GC 41-044-48


Fault Codes	Meaning	Possible Cause
F.00	Flow-NTC open circuit: NTC broken; NTC cable broken; Defective connection at NTC Defective connection at electronics	Flow-NTC cable defective/ broken NTC faulty
F.01	Return NTC open circuit: NTC broken; NTC cable broken; Defective connection at NTC Defective connection at electronics	Return-NTC cable defective/broken NTC faulty
F.02	Domestic hot water outlet NTC open circuit (combination boiler only)	NTC-connector not plugged in or loose, NTC defective connector on the electronics not plugged in correctly, cable defective
F.10	Flow NTC short circuit	NTC defective, cable/casing shortcut
F.11	Return NTC short circuit	NTC defective, cable/casing shortcut
F.13	Tank NTC short circuit	NTC defective, a short circuit in cable harness, cable/casing shortcut
F.20	Safety temperature limiter by NTC activated	Flow-NTC not correctly thermal-connected or defective; appliance does not shut down
F.22	Dry fire / Low water in system / Overheat	Too little water in your system, you have a defective pump and/or water pressure sensor or the pump lead is defective
F.23	Water shortage, the temperature difference between flow and return NTC too large	Pump blocked or defective, pump output too low, flow and return NTC interchanged
F.24	Water shortage, temperature rise too quick	Pump could be obstructed, running at low capacity, could be air trapped or the pressure might be too low.
F.28	The appliance does not start: Attempts to ignite during the start failed	Faults in the gas supply such as: - Gas meter or gas pressure detector defective - Air in gas - Gas flow pressure too low - Fire protection tap has disengaged Faults in the gas valve, wrong gas setting, igniter (ignition transformer, ignition cable, ignition plug) defective, ionisation current stopped (cable, electrode), faulty earthing in the appliance, electronics defective
F.29	The flame goes out during operation and subsequent ignition attempts failed	Gas supply temporarily stopped, faulty earthing of appliance
F.32	Fan speed variation	Fan blocked, plug not inserted correctly on fan, hall sensor defective, fault in cable harness, electronics defective
F.49	eBUS Undervoltage	Short circuit on eBUS, overload on eBUS or two power sources on eBUS with different polarity
F.61	Gas valve control defective	Short circuit/earth (ground) leak in cable harness to gas valves, gas valve assembly defective (earth/ground leak from coils), electronic control system defective
F.62	Gas valve shutoff delay	Gas valve leaking, electronics defective
F.63	EEPROM (Electrically Erasable Programmable Read-Only Memory) error	EMC or Electronic fault. Electronics defective
F.64	An electronic system or NTC sensor fault	Short-circuit in flow or return NTC or electronics defective
F.65	Electronic system temperature too high	This can happen because of an external heat source or an electrical fault
F.70	No valid DSN in display and/or mainboard	Spare part failure display and maiboard interchanged at same time and device specific number not adjusted
F.71	Flow NTC reports constant value (stuck at)	Flow NTC is defective
F.72	Flow and/or return NTC fault	Flow and/or return NTC is defective (tolerances too big)
F.73	Water pressure sensor signal out of range (too low)	Cable to water pressure sensor is broken or has a short-circuit at 0 V or water pressure sensor defective