Vaillant boilers are known for their reliability and efficiency. However, like all machines, they can occasionally encounter issues. Fault codes are displayed on the boilers to indicate these specific problems.

Understanding these codes can help you identify and resolve common issues promptly. In this guide, we will list the fault codes and provide tips to help you understand the common causes and possible solutions.

For more complex issues, always consult professional boiler repair experts. We are here to help. From decoding the boiler error codes for you to fixing the issues, our Gas Safe registered engineers can help with anything and everything regarding boilers. Call 07377 519 529 or email info@inspireelectrics.com today.

Is your Vaillant boiler flashing error codes? Worry not – if this blog isn’t sufficient, our team at Gas Tech Heating is here to assist you with expert and lasting repairs!

List Of Vaillant Boiler Fault Codes

1. Vaillant ecoTEC 65kW Boiler Fault Codes

0: Heating issue, no heat demand
1: Fan start-up error
2: Pump flow error
3: Ignition problem
4: Burner on error
6: Fan overrun error
7: Pump overrun error
8: Heating remaining cut off
31: No heat demand (summer mode)
34: Frost protection error
20: Hot water requirement error
22: Pump flow error
24: Burner on (hot water operation)
85: Service message (water circulation)

2. Vaillant EcoTEC Pro 28 / ecoTEC Plus Boiler Codes

00 / F.0: Flow temperature sensor interruption
01 / F.1: Return temperature sensor interruption
10: Flow NTC short circuit
11: Return NTC short circuit
20: Safety switch off temperature limiter
22: Low water pressure
23: Temperature difference too great
24: Temperature rising too fast
25: Flue gas temperature too high
26: Gas valve error
27: Flame simulation error
28: Ignition failure
29: Re-ignition failure
32: Fan error
49: eBUS error
61: Gas valve regulation error
62: Gas valve switch off delay
63: EEPROM error
64: Electronics/NTC error
65: Electronic temperature error
67: Electronics flame signal error
68: Unstable flame signal
70: Invalid device specific number
71: Flow temperature sensor signal constant
72: Flow return temperature difference too great
73: Water pressure sensor signal too low
74: Water pressure sensor signal too high
75: No pressure change detection
76: Overheating protection on
77: Flue non-return flap error
78: DHW outlet sensor interruption
83: Flow/return temperature sensor error
84: Temperature changing error
85: Sensor incorrectly fitted
CONNECTION: No communication with PCB
00: No heat demand
01: Fan start-up
02: Pump running
03: Ignition sequence error
04: Burner ignited
06: Fan overrun error
07: Pump overrun error
08: Heating remaining cut off time
10: Hot water demand via impeller sensor
11: DHW mode fan start up error
13: DHW mode ignition error
14: Hot water demand via fan sensor error
15: DHW mode pump and fan overrun
16: Fan overrun error
17: Pump overrun error
20: Burner on error
21: Fan start up error
22: Pump running error
23: Ignition error
24: Burner error
25: Pump or fan overrun error
26: Fan overrun
27: Pump overrun
28: Burner anti-cycling time
30: Room thermostat blocking heating mode
31: Summer operating mode
32: Fan speed deviation
34: Frost protection error
39: Burner off contact triggered
40: Comfort safety mode active
41: Water pressure > 2.8 bar
42: Flue non return flap signal blocks burner operation
46: Flame loss at minimum load
53: Water shortage
54: Blocking function
57: Comfort safety mode
58: Noise/wind error
61: Gas family check unsuccessful

3. Vaillant ecoTEC Plus Regular Boiler Gas Boiler Error Codes

0: Heating part load error
1: Water pump overrun
2: Max burner anti-cycling period
3: Hot water flow temperature reading
4: Warm stat sensor temperature
5: Flow temperature set value
7: Warm start temperature target
8: External controls heat demand
9: Flow target temperature from external regulator
10: Internal heating pump error
11: External heating pump error
12: Cylinder charging pump
13: Hot water circulation pump
15: Pump speed actual value
22: Hot water demand
23: Summer/Winter function
25: Hot water activation via eBus control
30: Control signal for gas valves
33: Fan speed target value
34: Fan speed actual value
40: Flow temperature target value
41: Return temperature actual value
44: Ionisation error
47: Outside temperature
76: Burner anti-cycling time remaining
90: Digital regulator status
91: DCF status
97: Second diagnostic level activation
98: Contact heating engineer
14: Pump speed target value
17: Heating flow return regulation
18: Pump operating mode
20: Maximum target cylinder value
26: Relay control ecoTec
27: Accessory relay 1
28: Accessory relay 2
50: Minimum speed offset
51: Maximum speed offset
60: Safety temperature cut offs
61: Unsuccessful lockouts
64: Average ignition times
65: Maximum ignition time
67: Burner anti-cycling time remaining
68: First attempt unsuccessful ignitions
69: Second attempt unsuccessful ignitions
70: Diverter valve position
71: Heater control knob maximum setting
72: Pump overrun time
75: Storage charging time
77: Cylinder charging output limitation
78: Cylinder charging temperature limitation
80: Heating operating hours
81: Hot water generation operating hours
82: Burner start up in heating mode
83: Burner start up in hot water mode
84: Maintenance indicator hours remaining
93: Appliance variant setting
96: Factory setting

4. Vaillant ecoMAX Pro 18/28E Boiler Fault Codes

1: Lack of gas, ignition, or flue fault
4: Ignition fault
5: Overheating fault
6: Flow NTC fault
17: Polarity check
24: Pump-related faults

How To Fix Common Vaillant Boiler Fault And Error Codes

While offering tips to fix all the above-mentioned fault codes in one article would be rather difficult, we have listed down some of the common issues and codes to still be able to help you as much as possible.

Please note that some of these steps or suggestions may require expert help. It is advisable that you get in touch with a professional to tackle the error codes in order to maintain the efficiency of your boiler.

1. F22 Fault Code (Low Water Pressure)

Ensure the pressure gauge reads 1-1.5 bar. Use the filling loop if pressure is low and bleed radiators to release trapped air.

2. F28 Fault Code (Ignition Failure)

Confirm the gas supply is on and inspect the ignition area for any visible damage or obstructions. Reset the boiler following the manufacturer’s guidelines.

3. F29 Fault Code (Flame Extinguished)

Check the flue for blockages, ensure a consistent gas supply, and attempt to reset the boiler. Seek professional assistance if the issue persists.

4. F32 Fault Code (Fan Error)

Examine the fan for any potential obstructions or signs of malfunction. Listen for unusual noises and replace the fan if necessary.

5. F75 Fault Code (No Pressure Change Detected)

Verify that the pump is operational and inspect the pressure sensor for any signs of damage. Consider contacting a professional for repair or replacement.

6. F62 Fault Code (Gas Valve Switch Off Delay)

Turn off the boiler and restart it after a brief interval. Check the gas valve for visible damage and consult a qualified engineer if the problem persists.

7. F20 Fault Code (Overheat)

Power down the boiler to allow it to cool. Inspect the system for any blockages and ensure all vents and ducts are clear.

8. F61 Fault Code (Gas Valve Control Fault)

Check the gas valve control for issues, reset the boiler, and ensure proper functioning before seeking professional help if needed.

9. F71 Fault Code (Digital Communication Fault – Hardware Fault)

Power down the boiler and check for hardware faults in the digital communication system. Contact a professional for detailed diagnosis and repair.

10. F74 Fault Code (Digital Communication Fault – NVM Error)

Restart the boiler and inspect for NVM (Non-Volatile Memory) errors. Seek professional assistance for repair or replacement if needed.

Contact Gas Tech Heating

Let Our Experts At Gas Tech Heating Help You!

Gas Tech Heating offers swift, cost-effective boiler repairs in Hemel Hempstead and nearby areas, ensuring uninterrupted heating and hot water. As Gas Safe engineers (Gas Safe number: 566188), we prioritise safety and efficiency while providing clear explanations and effective solutions.

Our skilled team handles all boiler types – from combination to system boilers – and excels in repairing top brands like Vaillant, Baxi, Worcester Bosch, Viessmann, and Ideal, alongside expertise in various other manufacturers.

Contact us today to discuss your requirements. We’ll offer prompt assistance.