Immergas
Immergas Water Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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01
Water heater does not ignite; display shows error 01 shortly after a hot water demand.
Ignition Failure / No Flame Detection
02
Water heater locks out with error 02; burner lights briefly then shuts down.
Flame Signal Loss During Operation
03
Unit attempts to start but quickly shows error 03; fan may not run or runs briefly.
Flue Gas Exhaust / Fan Failure
04
Display shows error 04 and the water heater will not start; may occur immediately on power‑up.
Primary Flow Temperature Sensor Fault (NTC Open/Short)
05
Error 05 displayed; unit may overheat quickly or shut down during operation.
Primary Return Temperature Sensor Fault (NTC Open/Short)
06
Error 06 appears; water temperature on the display is unrealistic (very high or very low) and burner does not operate correctly.
Domestic Hot Water (DHW) Temperature Sensor Fault
07
Error 07; unit overheats and shuts down, sometimes with loud boiling noises from inside the heater.
Overheat Thermostat / Safety Limit Tripped
08
Error 08 displayed; unit may not detect water flow when a hot tap is opened, or may run pump without burner ignition.
Flow Sensor / Flow Switch Fault
09
Error 09; unit indicates low water pressure or no water in the primary circuit.
Low System Pressure / Water Pressure Switch Open
10
Error 10; unit indicates overpressure or abnormal pressure reading in the primary circuit.
High System Pressure / Pressure Sensor Range Error
11
Error 11; unit reports flue gas sensor or safety device fault and will not operate.
Flue Gas Temperature Sensor / Safety Thermostat Fault
12
Error 12; unit indicates fan speed or air flow control error.
Fan Speed Control / Tachometer Fault
13
Error 13; unit reports ionization fault or flame present when there should be none.
False Flame Detection / Ionization Circuit Error
14
Error 14; unit indicates gas valve or modulation fault, burner may not modulate correctly.
Gas Valve Control / Modulation Error
15
Error 15; unit indicates communication error between main control board and user interface/display.
Communication Bus Fault
20
Error 20; unit indicates condensate drainage problem or condensate level fault.
Condensate Drain Blockage
21
Error 21; unit indicates domestic hot water flow rate or temperature regulation fault.
DHW Modulation / Flow Regulation Error
27
Error 27; unit indicates ionization current too low or unstable during operation.
Weak Flame Ionization Signal
28
Error 28; unit indicates primary circuit circulation fault or pump problem.
Circulation Pump Failure / Blocked Circuit
29
Error 29; unit indicates flue gas recirculation or combustion quality fault.
Combustion / Flue Recirculation Error
31
Error 31; unit indicates external sensor or remote control communication fault (if fitted).
External Temperature Sensor / Remote Interface Fault
37
Error 37; unit indicates internal memory or configuration error.
Control Board Configuration / EEPROM Fault
Symptom
Condensate water is dripping from joints in the flue rather than from the condensate drain.
Flue Condensate Leakage
Symptom
Display is blank but the unit appears to run (hot water is produced).
Display Backlight / LCD Failure
Symptom
Display is on but buttons do not respond or respond intermittently.
User Interface Keypad Failure
Symptom
Hot water is only lukewarm even with tap fully open; no error code shown.
Insufficient DHW Heating
Symptom
Hot water temperature is scalding even at moderate control settings.
Overheating DHW Outlet
Symptom
There is a smell of gas near the water heater, but the unit may still operate.
Gas Leak at Appliance
Symptom
There is a strong smell of combustion products or fumes around the water heater.
Flue Gas Spillage / Venting Problem
Symptom
Water heater does not start at all; no lights or display, completely dead.
No Power / Electrical Supply Failure
Symptom
Water heater emits a high‑pitched whistling or howling noise during operation.
Gas Flow / Burner Resonance Noise
Symptom
Water heater frequently cycles on and off rapidly when there is a small hot water demand.
Short Cycling on Low DHW Demand
Symptom
Water heater is leaking water from the bottom of the casing.
Internal Water Leak
Symptom
Water heater makes loud banging or knocking noises when heating.
Kettling / Boiling in Heat Exchanger
Symptom
Water heater powers on but does not ignite when a hot water tap is opened; no error code displayed.
No DHW Demand Recognition
Symptom
Water heater trips the household RCD (residual current device) or GFCI when it starts.
Earth Leakage / Electrical Insulation Fault
Symptom
Water heater vibrates excessively or rattles when the fan or pump runs.
Mechanical Vibration / Mounting Fault
Symptom
Water heater's pressure gauge rises when heating and then discharges water from the safety valve.
Expansion Vessel Failure / Overpressure
Symptom
Water temperature fluctuates between hot and cold during a shower without any error code.
Intermittent DHW Temperature Regulation
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| 01 |
Water heater does not ignite; display shows error 01 shortly after a hot water demand.
|
Ignition Failure / No Flame Detection | View Details |
| 02 |
Water heater locks out with error 02; burner lights briefly then shuts down.
|
Flame Signal Loss During Operation | View Details |
| 03 |
Unit attempts to start but quickly shows error 03; fan may not run or runs briefly.
|
Flue Gas Exhaust / Fan Failure | View Details |
| 04 |
Display shows error 04 and the water heater will not start; may occur immediately on power‑up.
|
Primary Flow Temperature Sensor Fault (NTC Open/Short) | View Details |
| 05 |
Error 05 displayed; unit may overheat quickly or shut down during operation.
|
Primary Return Temperature Sensor Fault (NTC Open/Short) | View Details |
| 06 |
Error 06 appears; water temperature on the display is unrealistic (very high or very low) and burner does not operate correctly.
|
Domestic Hot Water (DHW) Temperature Sensor Fault | View Details |
| 07 |
Error 07; unit overheats and shuts down, sometimes with loud boiling noises from inside the heater.
|
Overheat Thermostat / Safety Limit Tripped | View Details |
| 08 |
Error 08 displayed; unit may not detect water flow when a hot tap is opened, or may run pump without burner ignition.
|
Flow Sensor / Flow Switch Fault | View Details |
| 09 |
Error 09; unit indicates low water pressure or no water in the primary circuit.
|
Low System Pressure / Water Pressure Switch Open | View Details |
| 10 |
Error 10; unit indicates overpressure or abnormal pressure reading in the primary circuit.
|
High System Pressure / Pressure Sensor Range Error | View Details |
| 11 |
Error 11; unit reports flue gas sensor or safety device fault and will not operate.
|
Flue Gas Temperature Sensor / Safety Thermostat Fault | View Details |
| 12 |
Error 12; unit indicates fan speed or air flow control error.
|
Fan Speed Control / Tachometer Fault | View Details |
| 13 |
Error 13; unit reports ionization fault or flame present when there should be none.
|
False Flame Detection / Ionization Circuit Error | View Details |
| 14 |
Error 14; unit indicates gas valve or modulation fault, burner may not modulate correctly.
|
Gas Valve Control / Modulation Error | View Details |
| 15 |
Error 15; unit indicates communication error between main control board and user interface/display.
|
Communication Bus Fault | View Details |
| 20 |
Error 20; unit indicates condensate drainage problem or condensate level fault.
|
Condensate Drain Blockage | View Details |
| 21 |
Error 21; unit indicates domestic hot water flow rate or temperature regulation fault.
|
DHW Modulation / Flow Regulation Error | View Details |
| 27 |
Error 27; unit indicates ionization current too low or unstable during operation.
|
Weak Flame Ionization Signal | View Details |
| 28 |
Error 28; unit indicates primary circuit circulation fault or pump problem.
|
Circulation Pump Failure / Blocked Circuit | View Details |
| 29 |
Error 29; unit indicates flue gas recirculation or combustion quality fault.
|
Combustion / Flue Recirculation Error | View Details |
| 31 |
Error 31; unit indicates external sensor or remote control communication fault (if fitted).
|
External Temperature Sensor / Remote Interface Fault | View Details |
| 37 |
Error 37; unit indicates internal memory or configuration error.
|
Control Board Configuration / EEPROM Fault | View Details |
| – |
Condensate water is dripping from joints in the flue rather than from the condensate drain.
|
Flue Condensate Leakage | View Details |
| – |
Display is blank but the unit appears to run (hot water is produced).
|
Display Backlight / LCD Failure | View Details |
| – |
Display is on but buttons do not respond or respond intermittently.
|
User Interface Keypad Failure | View Details |
| – |
Hot water is only lukewarm even with tap fully open; no error code shown.
|
Insufficient DHW Heating | View Details |
| – |
Hot water temperature is scalding even at moderate control settings.
|
Overheating DHW Outlet | View Details |
| – |
There is a smell of gas near the water heater, but the unit may still operate.
|
Gas Leak at Appliance | View Details |
| – |
There is a strong smell of combustion products or fumes around the water heater.
|
Flue Gas Spillage / Venting Problem | View Details |
| – |
Water heater does not start at all; no lights or display, completely dead.
|
No Power / Electrical Supply Failure | View Details |
| – |
Water heater emits a high‑pitched whistling or howling noise during operation.
|
Gas Flow / Burner Resonance Noise | View Details |
| – |
Water heater frequently cycles on and off rapidly when there is a small hot water demand.
|
Short Cycling on Low DHW Demand | View Details |
| – |
Water heater is leaking water from the bottom of the casing.
|
Internal Water Leak | View Details |
| – |
Water heater makes loud banging or knocking noises when heating.
|
Kettling / Boiling in Heat Exchanger | View Details |
| – |
Water heater powers on but does not ignite when a hot water tap is opened; no error code displayed.
|
No DHW Demand Recognition | View Details |
| – |
Water heater trips the household RCD (residual current device) or GFCI when it starts.
|
Earth Leakage / Electrical Insulation Fault | View Details |
| – |
Water heater vibrates excessively or rattles when the fan or pump runs.
|
Mechanical Vibration / Mounting Fault | View Details |
| – |
Water heater's pressure gauge rises when heating and then discharges water from the safety valve.
|
Expansion Vessel Failure / Overpressure | View Details |
| – |
Water temperature fluctuates between hot and cold during a shower without any error code.
|
Intermittent DHW Temperature Regulation | View Details |
No matching codes found
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