IBC
IBC Boilers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E01
Boiler will not ignite; display shows E01 shortly after a call for heat or domestic hot water.
Ignition Failure Lockout
E02
Boiler attempts to start but shuts down with E02; fan may run briefly, burner does not stay lit.
Flame Detection Failure
E03
Boiler locks out with E03; fan may not start or stops quickly; no ignition attempt.
Combustion Fan/Air Proving Fault
E04
Boiler shuts down with E04; display may indicate high limit or overheat; unit is hot to the touch.
High Limit Temperature Lockout
E05
Boiler displays E05 and will not fire; may occur immediately on power-up or during operation.
Supply Temperature Sensor Fault
E06
Boiler shows E06; may continue to run at reduced performance or shut down depending on the model.
Return Temperature Sensor Fault
E07
Boiler locks out with E07; may indicate flue temperature too high or a flue sensor fault.
Flue Temperature Sensor/Overheat Fault
E08
Boiler displays E08; unit may not start or may shut down intermittently.
Outdoor Temperature Sensor Fault
E09
Boiler displays E09 and will not fire; may be accompanied by a low system pressure reading.
Low Water Pressure / System Pressure Switch Fault
E10
Boiler locks out with E10; this may indicate high system pressure or a pressure sensor error.
High Water Pressure / Pressure Sensor Range Fault
E11
Boiler displays E11; the burner may shut down unexpectedly during operation.
Flame Loss During Operation
E12
Boiler displays E12; this may indicate fan speed out of range or a fan feedback error.
Combustion Fan Speed / Feedback Fault
E13
Boiler displays E13; this may be associated with condensate issues or a blocked drain.
Condensate Drain / Float Switch Fault
E14
Boiler locks out with E14; this may indicate a domestic hot water (DHW) sensor fault on combi models.
DHW Temperature Sensor Fault
E15
Boiler displays E15; this may indicate a flow switch or flow sensor issue, especially on combi units.
DHW Flow Detection Fault
E16
Boiler displays E16; this may indicate an internal communication error between control modules.
Internal Control Communication Fault
E17
Boiler displays E17; this may be associated with sensor calibration or a parameter error.
Configuration / Parameter Fault
E18
Boiler locks out with E18; this may indicate a gas valve or gas train fault.
Gas Valve Control Fault
E19
Boiler displays E19, which may indicate a pump or flow-related fault on the primary circuit.
Primary Pump / Flow Fault
E20
Boiler displays E20, which may indicate a low voltage or power supply issue.
AC Supply / Low Voltage Fault
Symptom
Boiler cycles on and off while maintaining a constant low-level noise even when there is no call for heat or hot water.
Standby Pump Overrun / Ghost Flow
Symptom
Boiler display backlight works but text is missing, garbled, or unreadable.
Display / User Interface Failure
Symptom
Boiler display shows normal operation but there is no hot water at taps on a combi model.
No Domestic Hot Water Production
Symptom
Boiler emits a strong exhaust or burning smell near the unit or vent termination.
Abnormal Combustion / Venting Issue
Symptom
Boiler frequently goes into lockout during very cold weather but runs normally at milder temperatures.
Cold Weather Operational Issues
Symptom
Boiler frequently needs manual resetting to restore operation, even though different error codes may appear intermittently.
Intermittent Lockouts / Unstable Operation
Symptom
Boiler frequently short cycles, turning on and off every few minutes during a call for heat.
Short Cycling
Symptom
Boiler ignites with a loud pop or boom at startup.
Delayed Ignition
Symptom
Boiler is leaking water from the bottom of the cabinet or from piping connections near the unit.
General Water Leak
Symptom
Boiler makes loud banging or knocking noises when starting or during operation.
Kettling / Water Hammer in Heat Exchanger
Symptom
Boiler or nearby piping vibrates excessively during operation; humming or rattling noises are heard.
Mechanical Vibration / Resonance
Symptom
Boiler pressure rises significantly when heating and the relief valve occasionally discharges water.
Thermal Expansion / Overpressure
Symptom
Boiler runs, but radiators or in-floor heating remain lukewarm or cold.
Insufficient Space Heating Output
Symptom
Boiler will not start at all; the display is blank, and no lights are on.
No Power / Dead Boiler
Symptom
Domestic hot water temperature fluctuates or is not hot enough on a combi boiler.
Unstable DHW Temperature
Symptom
The boiler display is on, but there is no response to thermostat calls; the unit stays in standby.
No Call for Heat Recognition
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Boiler will not ignite; display shows E01 shortly after a call for heat or domestic hot water.
|
Ignition Failure Lockout | View Details |
| E02 |
Boiler attempts to start but shuts down with E02; fan may run briefly, burner does not stay lit.
|
Flame Detection Failure | View Details |
| E03 |
Boiler locks out with E03; fan may not start or stops quickly; no ignition attempt.
|
Combustion Fan/Air Proving Fault | View Details |
| E04 |
Boiler shuts down with E04; display may indicate high limit or overheat; unit is hot to the touch.
|
High Limit Temperature Lockout | View Details |
| E05 |
Boiler displays E05 and will not fire; may occur immediately on power-up or during operation.
|
Supply Temperature Sensor Fault | View Details |
| E06 |
Boiler shows E06; may continue to run at reduced performance or shut down depending on the model.
|
Return Temperature Sensor Fault | View Details |
| E07 |
Boiler locks out with E07; may indicate flue temperature too high or a flue sensor fault.
|
Flue Temperature Sensor/Overheat Fault | View Details |
| E08 |
Boiler displays E08; unit may not start or may shut down intermittently.
|
Outdoor Temperature Sensor Fault | View Details |
| E09 |
Boiler displays E09 and will not fire; may be accompanied by a low system pressure reading.
|
Low Water Pressure / System Pressure Switch Fault | View Details |
| E10 |
Boiler locks out with E10; this may indicate high system pressure or a pressure sensor error.
|
High Water Pressure / Pressure Sensor Range Fault | View Details |
| E11 |
Boiler displays E11; the burner may shut down unexpectedly during operation.
|
Flame Loss During Operation | View Details |
| E12 |
Boiler displays E12; this may indicate fan speed out of range or a fan feedback error.
|
Combustion Fan Speed / Feedback Fault | View Details |
| E13 |
Boiler displays E13; this may be associated with condensate issues or a blocked drain.
|
Condensate Drain / Float Switch Fault | View Details |
| E14 |
Boiler locks out with E14; this may indicate a domestic hot water (DHW) sensor fault on combi models.
|
DHW Temperature Sensor Fault | View Details |
| E15 |
Boiler displays E15; this may indicate a flow switch or flow sensor issue, especially on combi units.
|
DHW Flow Detection Fault | View Details |
| E16 |
Boiler displays E16; this may indicate an internal communication error between control modules.
|
Internal Control Communication Fault | View Details |
| E17 |
Boiler displays E17; this may be associated with sensor calibration or a parameter error.
|
Configuration / Parameter Fault | View Details |
| E18 |
Boiler locks out with E18; this may indicate a gas valve or gas train fault.
|
Gas Valve Control Fault | View Details |
| E19 |
Boiler displays E19, which may indicate a pump or flow-related fault on the primary circuit.
|
Primary Pump / Flow Fault | View Details |
| E20 |
Boiler displays E20, which may indicate a low voltage or power supply issue.
|
AC Supply / Low Voltage Fault | View Details |
| – |
Boiler cycles on and off while maintaining a constant low-level noise even when there is no call for heat or hot water.
|
Standby Pump Overrun / Ghost Flow | View Details |
| – |
Boiler display backlight works but text is missing, garbled, or unreadable.
|
Display / User Interface Failure | View Details |
| – |
Boiler display shows normal operation but there is no hot water at taps on a combi model.
|
No Domestic Hot Water Production | View Details |
| – |
Boiler emits a strong exhaust or burning smell near the unit or vent termination.
|
Abnormal Combustion / Venting Issue | View Details |
| – |
Boiler frequently goes into lockout during very cold weather but runs normally at milder temperatures.
|
Cold Weather Operational Issues | View Details |
| – |
Boiler frequently needs manual resetting to restore operation, even though different error codes may appear intermittently.
|
Intermittent Lockouts / Unstable Operation | View Details |
| – |
Boiler frequently short cycles, turning on and off every few minutes during a call for heat.
|
Short Cycling | View Details |
| – |
Boiler ignites with a loud pop or boom at startup.
|
Delayed Ignition | View Details |
| – |
Boiler is leaking water from the bottom of the cabinet or from piping connections near the unit.
|
General Water Leak | View Details |
| – |
Boiler makes loud banging or knocking noises when starting or during operation.
|
Kettling / Water Hammer in Heat Exchanger | View Details |
| – |
Boiler or nearby piping vibrates excessively during operation; humming or rattling noises are heard.
|
Mechanical Vibration / Resonance | View Details |
| – |
Boiler pressure rises significantly when heating and the relief valve occasionally discharges water.
|
Thermal Expansion / Overpressure | View Details |
| – |
Boiler runs, but radiators or in-floor heating remain lukewarm or cold.
|
Insufficient Space Heating Output | View Details |
| – |
Boiler will not start at all; the display is blank, and no lights are on.
|
No Power / Dead Boiler | View Details |
| – |
Domestic hot water temperature fluctuates or is not hot enough on a combi boiler.
|
Unstable DHW Temperature | View Details |
| – |
The boiler display is on, but there is no response to thermostat calls; the unit stays in standby.
|
No Call for Heat Recognition | View Details |
No matching codes found
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