It is good when gas equipment is capable of self-diagnosis. Vaillant boiler errors indicate where to look for a breakdown. If you want to figure out the causes of the malfunction yourself, then study the meaning of the symbols on the display. And we will show you how to fix the situation without calling the wizard.
Vaillant gas boiler error codes can appear not only in the event of a breakdown. Some icons are displayed during the operation of the equipment, during the switching of modes. Symbols will help to understand the frequency of occurrence. For example, if the code begins with the letter “F” – this means an error (malfunction). If with the letter “S” – this is the state of the device.
If you see the symbols on the display for the first time, reset the boiler. Perhaps this is a system failure. If the code appears again, you need to understand the problem and fix the problem.
- sensor performance;
- wiring condition;
- plug connection.
F1 Break in return temperature sensor. F2 Fill temperature sensor open. Insert the plug tighter. Make sure the wiring is not damaged. F3 Drive thermal sensor circuit open. F5 (only for wall-mounted “Vailant Atmo”) Communication with the external smoke exhaust sensor has been interrupted. What to do:
- Pull contacts.
- Replace faulty wiring.
- Install the correct item.
F6 Internal retract sensor wires broken. F10 Short circuit (short circuit) of the thermistor on supply. Check:
- Plug. Tighten contacts, replace broken parts.
- Cable.
- Thermistor.
F11 Short circuit thermistor on the return. F13 Hot start sensor short circuit.
- Shorted cable. Install new wiring.
- Defects in the temperature control element. Replace items.
- Loose or shorted plug. Check the detail.
F15, 16 Short circuit of the external sensor for the removal of combustion products. F20 Operation blocked by overheating protection. The thermistor is defective, so the system does not respond to overheating. Install a work item. F22 Equipment operation stopped due to lack of water. Check:
- Pressure sensor.
- Circulation pump for jamming.
- Wiring from parts to the control module.
- Main fee.
The defective part must be replaced. The system may not match the pump capacity.
F23 Too little water in the boiler. Check that the flow and return sensors are properly connected. Clean the pump, it may be blocked by a foreign object. Or its performance is not enough to service the system. F24 Low coolant level. At the same time, the temperature rises sharply. The pressure drops. Remove excess air. See solutions for F23. F26 Problems with the operation of the gas fittings. Incorrect connection of the servomotor. Tighten the plug, replace damaged wires. F27 Flame detection with fuel valve closed. Carry out diagnostics of the protection system, magnetic valve. F28 The two-circuit device does not turn on. The burner does not start. Diagnose and repair:
- pressure switch;
- gas meter;
- gas fittings;
- main module.
Release excess air. Adjust fuel settings.
F29 The flame goes out.
Interruptions in gas supply. Wait until the supply is restored, or contact the gas service.
Check the grounding of the device.
F32/F37 (for condensing turbo models) The fan speed is not correct. Tighten the loose plugs, put a working fan. F33 (for turboTEC) The pressure measuring switch does not turn on. Problems with pressure switch contacts. Make contact calls and repairs. F36 Protection worked, weak traction. Combustion products enter the room.
- Shut off the gas supply, turn off the boiler.
- Open the ventilation, clean the chimney shaft from blockage.
F38 Fan failure. Repair or replace. F42 Open coding resistor. Measure the resistance of the resistor. Check the cable for a short. F49 Low voltage on the eBUS bus. The bus is shorted or the channel is overloaded. F53 Incorrect combustion control. Adjust dynamic pressure. Carry out diagnostics of the Venturi nozzle, gas fittings. F54 Fuel supply problem. How to fix the situation:
- Open the gas valve.
- Pressurize the system.
- Inspect the shut-off valve and check its serviceability.
F56 Component failure in the combustion unit. The contact with the fuel valve is broken, connect the plug. If the symbols reappear, check the valve. F57 Comfort mode on, incorrect adjustment. Ignition electrode corrosion. Clean the parts or install a new element. F61 An error has occurred in the control of the gas valves.
- Cable short circuit, circuit break.
- Fuel valve failure.
Carry out repairs. Replace components.
F62 Armature switches off with delay. The control electrode does not work. F63 EEPROM failure. Electronics failure. It is better to contact the service center. F64 / F67 Problems with electronics, sensors. Diagnose wiring, contacts, sensors. F65 Hot electronics compartment. Malfunction of parts, external heating of the block. F70 Wrong boiler number. After installing the new display and electronics, you did not enter the boiler code. F72 The flow or return temperature sensors are out of order.
- Broke, shorted wire.
- Install the correct item.
F73 The pressure sensor gives a low signal. F74 The pressure sensor is high. Wire shorted to 5-24V. Change connection. F75 When the pump is turned on, the pressure does not rise. Bleed air from the system, adjust the settings of the bypass, expansion tank. F76 Blocking from overheating of the primary radiator. Heat exchanger not working, fuse cable defective. F77 Malfunction of the diverter valve, condensate pump. Run diagnostics on parts. F80 in combination with F91 secondary radiator sensor short circuit. Tighten the contacts, repair faults. F81 in combination with F91 Faults in the loading pump. Bleed air from the pump. Inspect the sensor, cable, impeller. Make sure the heat exchanger is not clogged, clean it. F83 Incorrect thermistor measurement on the supply and return lines.
- Add coolant.
- Correct the location of the thermistor.
F84/F85 Thermistor data invalid. Swap the details. Wrong installation F92 Coding resistor error. Measure resistance, set gas group. F93 Combustion quality abnormal.
- Replace the nozzle with a suitable one.
- Clean the venturi nozzle.
Con No communication with the control unit. Contacting a service center. Fxx Software problem. 5ER Time for maintenance.
Intermediate codes may appear on the screen of the Vailant boiler. So, the symbols from S0 to S8 indicate the switched on heating mode. DHW heating in progress – S10 to S17. Hot start – S20-S28.
By studying the meanings of the codes, you can correct the errors. Carry out maintenance of the boiler once a year, then there will be no problems with operation.