Error Code	Symptom	Fault Type	Guide
–	Boiler in standby, no central heating or hot water demand active, display shows code 0	Standby / No Heat Demand	View Details
1	Boiler shows code 1, burner on for central heating or hot water, but user suspects poor performance	Normal Operation / Burner Active	View Details
10	Boiler displays error code 10 and will not start, no heating or hot water	Flow Temperature Sensor (CH NTC) Fault	View Details
11	Boiler displays error code 11, boiler locks out, no heating or hot water	Return Temperature Sensor (CH Return NTC) Fault	View Details
12	Boiler displays error code 12, hot water temperature unstable or boiler locks out on DHW demand	DHW Temperature Sensor (DHW NTC) Fault	View Details
13	Boiler displays error code 13, intermittent hot water temperature spikes or shutdown	Cold Water Inlet Sensor / Flow Sensor Temperature Fault	View Details
2	Boiler shows code 2, pump running but burner off, boiler appears to be in pump overrun or post-purge	Pump Overrun / Post-Heating Circulation	View Details
20	Boiler displays error code 20, boiler locks out, no heating or hot water	Flame Detection Fault / Flame Signal Lost	View Details
21	Boiler displays error code 21, ignition attempts fail, no flame established	Ignition Failure	View Details
22	Boiler displays error code 22, burner shuts down unexpectedly during operation	Flame Loss During Operation	View Details
23	Boiler displays error code 23, fan runs abnormally or boiler will not fire	Fan Speed / Air Pressure Fault	View Details
24	Boiler displays error code 24, boiler locks out, no heating or hot water	Water Pressure Sensor / Flow Switch Fault	View Details
25	Boiler displays error code 25, boiler overheats and shuts down	Overheat Protection / High Limit Trip	View Details
26	Boiler displays error code 26, frequent cycling and shutdown on temperature	Flow Temperature Too High / Flow Restriction	View Details
27	Boiler displays error code 27, burner output limited, poor heating performance	Modulation / Gas Valve Control Fault	View Details
28	Boiler displays error code 28, boiler will not start, control panel unresponsive or erratic	PCB / Control Board Fault	View Details
29	Boiler displays error code 29, low system pressure, boiler shuts down	Low Water Pressure Lockout	View Details
3	Boiler shows code 3, fan running but no ignition, boiler does not fire	Pre-Purge / Ignition Sequence Not Completing	View Details
30	Boiler displays error code 30, pressure rises rapidly when heating, then discharges via safety valve	Overpressure / Expansion Vessel Failure	View Details
4	Boiler shows code 4, burner off, pump may run briefly, no heating or hot water	No Heat Demand / End of Cycle	View Details
40	Boiler displays error code 40, no heating or hot water, fan does not start	Fan Fault / No Airflow	View Details
41	Boiler displays error code 41, intermittent fan operation, boiler locks out	Fan Speed / Tachometer Fault	View Details
5	Boiler shows code 5, burner off, pump may run, boiler appears to be in anti-cycling delay	Anti-Cycling / Minimum Off Time	View Details
50	Boiler displays error code 50, no heating or hot water, pump not running	Pump Fault / No Circulation	View Details
51	Boiler displays error code 51, pump runs continuously even with no demand	Pump Overrun Control Fault	View Details
6	Boiler shows code 6, burner off, pump running, boiler cooling down after demand	Pump Overrun / Post-Heating Cool Down	View Details
60	Boiler displays error code 60, hot water priority fault on combi or system with priority control	DHW Priority / Diverter Control Fault	View Details
7	Boiler shows code 7, burner off, no demand, frost protection or anti-legionella cycle may be active	Frost Protection / Special Operating Mode	View Details
70	Boiler displays error code 70, communication error between user interface and main PCB	Communication / Display Board Fault	View Details
–	Boiler condensate pipe repeatedly freezes in cold weather, causing lockouts	Frozen Condensate Pipe	View Details
–	Boiler emits a burning smell or plastic smell when running	Overheating Component / Electrical Overload	View Details
–	Boiler flue terminal has white staining or water dripping excessively	Condensate / Flue Gas Condensation Issue	View Details
–	Boiler frequently loses pressure and needs topping up every few days	Chronic Pressure Loss	View Details
–	Boiler leaking water from underneath the casing or from pipe connections	Internal Water Leak	View Details
–	Boiler makes gurgling noises, especially at startup or shutdown	Air in System / Condensate Gurgling	View Details
–	Boiler makes loud banging or knocking noises (kettling) during operation	Kettling / Localised Boiling in Heat Exchanger	View Details
–	Boiler occasionally trips the household RCD or blows fuses	Electrical Short / Earth Leakage	View Details
–	Boiler repeatedly turns on and off in short cycles without reaching set temperature	Short Cycling	View Details
–	Boiler runs but radiators do not heat up, hot water may still work on combi models	No Central Heating Output	View Details
–	Boiler runs for hot water but central heating only works when a hot tap is opened (on combi models)	Diverter Valve Stuck in DHW Position	View Details
–	Boiler vibrates excessively or resonates through the pipework when running	Mechanical Vibration / Resonance	View Details
–	Boiler will not start at all, display is blank or very dim	No Power / Dead Boiler	View Details
–	Hot water temperature fluctuates between hot and cold during use	Unstable DHW Temperature Control	View Details
–	Radiators only get warm at the bottom or some radiators stay cold while boiler runs	Poor Circulation / Sludged System	View Details

Intergas Boilers Error Codes

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