Riello
Riello Boilers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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A01
Boiler locks out shortly after a heat demand, with the red lockout light on the burner control, and no flame established.
Ignition Failure / Flame Not Detected
A02
Boiler attempts to start but shuts down with a lockout, the fan runs but no flame is established, often after several ignition attempts.
Flame Detection Failure After Ignition
A03
Boiler locks out with an overheat indication; the flow temperature is very high, and the boiler's flow pipe is very hot to the touch.
Overheat Thermostat Tripped
A04
Boiler displays a low water pressure fault, will not fire, and the pressure gauge is below minimum (often below 0.5 bar).
Low System Water Pressure
A05
Boiler shows a fan/air pressure fault, the burner does not ignite, and the fan may or may not run.
Air Pressure Switch / Fan Fault
A06
Boiler locks out with a flue/combustion fault; it may start then shut down repeatedly.
Flue Gas / Combustion Fault
A07
Boiler indicates flue temperature is too high and shuts down to protect the heat exchanger.
Excessive Flue Gas Temperature
A08
Boiler shows flow temperature sensor fault, may not start, or may run erratically.
Flow NTC Sensor Failure
A09
Boiler shows return temperature sensor fault, may cycle rapidly, or shut down.
Return NTC Sensor Failure
A10
Boiler indicates domestic hot water (DHW) sensor fault on a combi or system boiler with a cylinder sensor.
DHW NTC Sensor Failure
A11
Boiler shows flame present when there should be none, or fails to start due to false flame detection.
False Flame Signal / Ionisation Fault
A12
Boiler displays gas valve or fuel valve fault; no ignition sequence.
Gas/Oil Valve Control Fault
A13
Boiler shows pump fault; it will not fire or shuts down on overheat.
Primary Circulation Pump Failure
A14
Boiler indicates flue sensor or safety thermostat fault; it may lock out.
Flue Safety Thermostat / Sensor Failure
A15
Boiler shows condensate fault, often during cold weather; the boiler will not fire.
Blocked or Frozen Condensate Drain
A16
Boiler displays a communication error between the main PCB and burner control or remote controller.
Control Communication Fault
A17
Boiler shows thermostat or room control fault; it will not respond to demand.
External Control / Thermostat Fault
A18
Boiler indicates flame loss during operation, cycles on and off with lockouts.
Unstable Flame / Intermittent Flame Failure
A19
Boiler shows lockout immediately on start with no fan or pump operation.
Internal Control Self-Check Failure
A20
Boiler indicates high system pressure, may discharge water from the safety valve and shut down.
High System Pressure
Symptom
Boiler casing or flue joints show signs of soot or staining
Flue Gas Leakage
Symptom
Boiler cycles on and off rapidly without reaching set temperature
Short Cycling
Symptom
Boiler display is on but unresponsive, buttons do not work or menu is frozen
Control Panel / User Interface Fault
Symptom
Boiler fan runs continuously even when there is no demand for heat
Fan Overrun / Stuck Relay
Symptom
Boiler frequently loses pressure and needs topping up every few days.
Chronic System Water Loss
Symptom
Boiler frequently trips the household RCD or MCB when starting
Electrical Short or Earth Leakage
Symptom
Boiler ignites but then shuts down after a few seconds repeatedly
Post-Ignition Flame Dropout
Symptom
Boiler is leaking water from underneath or from casing joints.
Internal Water Leak
Symptom
Boiler lockout occurs mainly in very cold weather when an external condensate pipe is present.
Frozen Condensate Pipe
Symptom
Boiler makes loud banging or knocking noises (kettling) during operation.
Boiler Kettling / Localised Boiling
Symptom
Boiler or flue emits unusual rumbling or roaring noise during firing.
Combustion Instability
Symptom
Boiler provides heating but not hot water to cylinder on system/regular boilers
No Cylinder Heating
Symptom
Boiler runs but radiators do not get hot or only partially heat up.
Poor Central Heating Circulation
Symptom
Boiler runs for heating but does not provide domestic hot water (combi models)
No DHW Production
Symptom
Boiler starts normally but shuts down when multiple radiators heat up
Flow Restriction Under Load
Symptom
Boiler will not start at all, no lights or display, completely dead.
No Power to Boiler
Symptom
Domestic hot water temperature fluctuates or runs hot then cold on a combi boiler
Unstable DHW Temperature Control
Symptom
Strong smell of gas or oil around the boiler or burner.
Fuel Leak / Incomplete Combustion
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| A01 |
Boiler locks out shortly after a heat demand, with the red lockout light on the burner control, and no flame established.
|
Ignition Failure / Flame Not Detected | View Details |
| A02 |
Boiler attempts to start but shuts down with a lockout, the fan runs but no flame is established, often after several ignition attempts.
|
Flame Detection Failure After Ignition | View Details |
| A03 |
Boiler locks out with an overheat indication; the flow temperature is very high, and the boiler's flow pipe is very hot to the touch.
|
Overheat Thermostat Tripped | View Details |
| A04 |
Boiler displays a low water pressure fault, will not fire, and the pressure gauge is below minimum (often below 0.5 bar).
|
Low System Water Pressure | View Details |
| A05 |
Boiler shows a fan/air pressure fault, the burner does not ignite, and the fan may or may not run.
|
Air Pressure Switch / Fan Fault | View Details |
| A06 |
Boiler locks out with a flue/combustion fault; it may start then shut down repeatedly.
|
Flue Gas / Combustion Fault | View Details |
| A07 |
Boiler indicates flue temperature is too high and shuts down to protect the heat exchanger.
|
Excessive Flue Gas Temperature | View Details |
| A08 |
Boiler shows flow temperature sensor fault, may not start, or may run erratically.
|
Flow NTC Sensor Failure | View Details |
| A09 |
Boiler shows return temperature sensor fault, may cycle rapidly, or shut down.
|
Return NTC Sensor Failure | View Details |
| A10 |
Boiler indicates domestic hot water (DHW) sensor fault on a combi or system boiler with a cylinder sensor.
|
DHW NTC Sensor Failure | View Details |
| A11 |
Boiler shows flame present when there should be none, or fails to start due to false flame detection.
|
False Flame Signal / Ionisation Fault | View Details |
| A12 |
Boiler displays gas valve or fuel valve fault; no ignition sequence.
|
Gas/Oil Valve Control Fault | View Details |
| A13 |
Boiler shows pump fault; it will not fire or shuts down on overheat.
|
Primary Circulation Pump Failure | View Details |
| A14 |
Boiler indicates flue sensor or safety thermostat fault; it may lock out.
|
Flue Safety Thermostat / Sensor Failure | View Details |
| A15 |
Boiler shows condensate fault, often during cold weather; the boiler will not fire.
|
Blocked or Frozen Condensate Drain | View Details |
| A16 |
Boiler displays a communication error between the main PCB and burner control or remote controller.
|
Control Communication Fault | View Details |
| A17 |
Boiler shows thermostat or room control fault; it will not respond to demand.
|
External Control / Thermostat Fault | View Details |
| A18 |
Boiler indicates flame loss during operation, cycles on and off with lockouts.
|
Unstable Flame / Intermittent Flame Failure | View Details |
| A19 |
Boiler shows lockout immediately on start with no fan or pump operation.
|
Internal Control Self-Check Failure | View Details |
| A20 |
Boiler indicates high system pressure, may discharge water from the safety valve and shut down.
|
High System Pressure | View Details |
| – |
Boiler casing or flue joints show signs of soot or staining
|
Flue Gas Leakage | View Details |
| – |
Boiler cycles on and off rapidly without reaching set temperature
|
Short Cycling | View Details |
| – |
Boiler display is on but unresponsive, buttons do not work or menu is frozen
|
Control Panel / User Interface Fault | View Details |
| – |
Boiler fan runs continuously even when there is no demand for heat
|
Fan Overrun / Stuck Relay | View Details |
| – |
Boiler frequently loses pressure and needs topping up every few days.
|
Chronic System Water Loss | View Details |
| – |
Boiler frequently trips the household RCD or MCB when starting
|
Electrical Short or Earth Leakage | View Details |
| – |
Boiler ignites but then shuts down after a few seconds repeatedly
|
Post-Ignition Flame Dropout | View Details |
| – |
Boiler is leaking water from underneath or from casing joints.
|
Internal Water Leak | View Details |
| – |
Boiler lockout occurs mainly in very cold weather when an external condensate pipe is present.
|
Frozen Condensate Pipe | View Details |
| – |
Boiler makes loud banging or knocking noises (kettling) during operation.
|
Boiler Kettling / Localised Boiling | View Details |
| – |
Boiler or flue emits unusual rumbling or roaring noise during firing.
|
Combustion Instability | View Details |
| – |
Boiler provides heating but not hot water to cylinder on system/regular boilers
|
No Cylinder Heating | View Details |
| – |
Boiler runs but radiators do not get hot or only partially heat up.
|
Poor Central Heating Circulation | View Details |
| – |
Boiler runs for heating but does not provide domestic hot water (combi models)
|
No DHW Production | View Details |
| – |
Boiler starts normally but shuts down when multiple radiators heat up
|
Flow Restriction Under Load | View Details |
| – |
Boiler will not start at all, no lights or display, completely dead.
|
No Power to Boiler | View Details |
| – |
Domestic hot water temperature fluctuates or runs hot then cold on a combi boiler
|
Unstable DHW Temperature Control | View Details |
| – |
Strong smell of gas or oil around the boiler or burner.
|
Fuel Leak / Incomplete Combustion | View Details |
No matching codes found
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