Immergas Repair Service

What does the 20 error mean on an Immergas boiler?

The 20 error on an Immergas boiler indicates a parasite flame block. The flame detection system is sensing a flame signal when the boiler should not be firing, which could indicate a leak in the detection circuit or a flame control unit anomaly. If you smell gas, do not operate any switches, ventilate the area if safe to do so, leave the property immediately, and call the gas emergency service from outside. If there is no gas smell, switch off the boiler at the electrical supply and do not attempt to restart. Contact a Gas Safe registered engineer immediately for inspection.

What does the 01 error mean on an Immergas boiler?

The 01 error on an Immergas boiler indicates an ignition failure block. The boiler has attempted to ignite but failed within the preset time. If you smell gas, do not operate any switches, ventilate the area if safe to do so, leave the property immediately, and call the gas emergency service from outside. If there is no gas smell, check that the gas supply is turned on and other gas appliances are working. Press the reset button once only. If the error recurs after reset, do not attempt further resets. Contact a Gas Safe registered engineer for professional diagnosis.

What does the 101 error mean on an Immergas heat pump?

The 101 error on an Immergas heat pump indicates a wiring fault between the control kit and outdoor unit. There is an electrical connection problem preventing proper communication. Switch off the heat pump at the isolator switch. Do not attempt to inspect or repair any wiring yourself. Contact a qualified technician to check the electrical connections between the indoor control unit and outdoor heat pump unit.

What does the 15 error mean on an Immergas boiler?

The 15 error on an Immergas boiler indicates a configuration error. The control board has detected an electrical wiring anomaly or an incompatibility in the system configuration. The boiler will not start until this is resolved. Switch off the boiler at the electrical supply. Do not attempt to reset or reconfigure the boiler yourself. Contact a qualified technician to diagnose the wiring fault and correct the configuration settings.

What does the 04 error mean on an Immergas boiler?

The 04 error on an Immergas boiler indicates a contacts resistance block, meaning there is a fault detected in the gas valve electrical supply circuit. If you smell gas, do not operate any switches, ventilate the area if safe to do so, leave the property immediately, and call the gas emergency service from outside. If there is no gas smell, switch off the boiler at the electrical supply. Do not attempt to reset. Contact a Gas Safe registered engineer for professional diagnosis and repair of the gas valve circuit.

Does my Immergas boiler have frost protection?

Yes, Immergas boilers include an antifreeze function. If the system water temperature inside the boiler falls below approximately 4°C, the boiler automatically starts both the pump and burner to heat the water to a safe temperature. This protection only functions when the boiler is connected to the electrical supply and operating normally, not in a fault or block state. During extended absences in cold weather, consider draining the system or adding appropriate antifreeze products to the heating water.

Why are some radiators not heating up when my Immergas boiler is running?

If some radiators remain cold while the boiler is running, trapped air may be the cause. Bleed each cold radiator using a radiator key by opening the bleed valve until water flows steadily, then close it. Ensure all radiator valves are open. Check that the system pressure is between 1.0 and 1.5 bar after bleeding. If radiators remain cold after bleeding, or if multiple radiators are affected, contact a qualified technician as there may be a circulation pump fault or system blockage.

At what temperature should I store hot water to prevent bacteria growth?

If your Immergas system includes a hot water storage cylinder, the water should be stored at a minimum of 60 degrees Celsius to prevent the growth of harmful bacteria including Legionella. Water at taps should reach at least 50 degrees Celsius within one minute of running. Some Immergas systems include an anti-legionella function that periodically raises the stored water temperature automatically. This does not apply to combi boilers which heat water on demand without storage.

What should I do if my Immergas heat pump outdoor unit is making unusual noises?

Some noise during operation is normal, particularly during defrost cycles when the reversing valve operates. However, unusual grinding, rattling, or continuous loud noises may indicate a fault requiring professional attention.

What is weather compensation on my Immergas heat pump?

Weather compensation automatically adjusts the flow temperature based on outdoor conditions. When it is colder outside, the system increases the water temperature to provide more heat. When it is warmer, the temperature is reduced to save energy. The system uses an outdoor temperature sensor to monitor conditions. This feature improves efficiency by preventing the heat pump from working harder than necessary. The heating curve settings are typically configured by your installer to suit your home.