Viadrus
Viadrus 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 does not ignite, burner does not start, display shows E01 shortly after a call for heat or hot water.
Ignition Failure / No Flame Detection
E02
Boiler locks out with E02, burner stops, circulation pump may continue to run for a short time. Flow temperature rises rapidly before shutdown.
Overheat Thermostat Tripped / Safety Temperature Limiter
E03
Boiler attempts to start but shuts down with E03. Fan may run briefly. No ignition. Often occurs on room-sealed Viadrus gas boilers with flue fan.
Flue Gas / Air Pressure Switch Fault
E04
Boiler display shows E04 and shuts down. Often associated with low or no water in the system. Radiators are cold and pressure gauge is near zero.
Low Water Pressure / Water Shortage Protection
E05
Boiler shows E05 and will not start. Flow temperature on the display may read very low or very high compared to actual pipe temperature.
Flow Temperature Sensor (NTC) Fault
E06
Boiler locks out with E06, domestic hot water (DHW) temperature is incorrect or not displayed, burner may not fire on hot water demand.
DHW Temperature Sensor (NTC) Fault
E07
Boiler shows E07 and stops. Often occurs after a power surge or wiring disturbance. Some relays may click but no normal operation.
Control Board Communication / Internal Fault
E08
Boiler displays E08, burner stops, and the circulation pump may continue to run. Often associated with flue gas temperature issues.
Flue Gas Temperature Sensor Fault / Overtemperature
E09
Boiler shows E09, burner does not start, and there may be no sound from the gas valve when a call for heat is present.
Gas Valve Control Fault
E10
Boiler displays E10, heating does not start, and the circulation pump may not run.
Circulation Pump Fault / No Flow Detection
E11
Boiler shows E11, burner stops, and there may be a strong smell of flue gases or evidence of poor combustion.
Flame Loss During Operation
E12
Boiler displays E12, no heating or hot water. Often associated with external control or thermostat issues.
External Control / Room Thermostat Communication Fault
E13
Boiler shows E13, often after a power cut or wiring change. Display may be blank or show partial information.
Display / User Interface Board Fault
E14
Boiler displays E14, burner does not start, and there may be no response to hot water demand.
DHW Flow Switch / Flow Sensor Fault
E15
Boiler shows E15 and shuts down. There may be water present in the base tray or under the boiler.
Water Leak / Safety Float Switch Activated
E16
Boiler displays E16, heating may work intermittently, and the fan speed seems abnormal (too high or too low).
Fan Speed / Modulation Control Fault
E17
Boiler shows E17, no heating, and the return temperature reading is abnormal or fixed.
Return Temperature Sensor (NTC) Fault
E18
Boiler displays E18, burner stops, and the system pressure may be too high.
High System Pressure / Pressure Sensor Fault
E19
Boiler shows E19, burner does not start, and there may be no response to external demand signals.
OpenTherm / Digital Communication Fault
E20
Boiler displays E20, burner stops, and the flue gas analysis test mode may not function correctly.
Combustion Control / Gas-Air Ratio Fault
Symptom
Boiler casing or nearby walls show signs of soot deposits or black staining.
Incomplete Combustion / Sooting
Symptom
Boiler emits unusual smells (burning, plastic, or flue gas odour) during operation.
Overheating Components / Flue Gas Leakage
Symptom
Boiler frequently loses pressure, requiring regular top-ups via the filling loop.
Chronic Pressure Loss
Symptom
Boiler frequently trips the electrical circuit breaker or blows fuses.
Electrical Short / Overcurrent
Symptom
Boiler is excessively noisy during operation (rumbling, whistling, or fan roaring).
Mechanical Noise / Combustion Noise
Symptom
Boiler leaking water from underneath or from side panels, puddles forming below Viadrus boiler.
Internal Water Leak
Symptom
Boiler lockout occurs mainly in very cold weather, flue terminal or condensate pipe may be icy.
Frozen Condensate / Flue Obstruction
Symptom
Boiler makes loud banging or knocking noises (kettling) during operation, especially when heating up.
Heat Exchanger Kettling / Localised Boiling
Symptom
Boiler produces central heating but no domestic hot water on a combi Viadrus boiler.
No DHW Production (Combi Boiler)
Symptom
Boiler produces hot water but no central heating, even when room thermostat is calling for heat.
Heating Demand / Diverter Fault (Combi) or External Valve Fault
Symptom
Boiler runs but room temperature overshoots setpoint or fluctuates widely.
Control / Thermostat Regulation Issue
Symptom
Boiler starts but shuts down after a few seconds, radiators remain cold, no error code displayed.
Short Cycling / Inadequate Flow
Symptom
Boiler will not start at all, no display or lights, completely dead.
No Power / Electrical Supply Fault
Symptom
Boiler’s automatic air vent constantly releases water or air, causing noise and pressure fluctuations.
Faulty Automatic Air Vent
Symptom
Boiler’s flue gas spillage safety device (on open-flue Viadrus models) trips, shutting down the boiler.
Flue Spillage / Draft Failure
Symptom
Boiler’s pilot (on older Viadrus models with standing pilot) will not stay lit or goes out frequently.
Pilot Flame Instability
Symptom
Boiler’s safety relief valve discharges water intermittently, even when pressure seems normal.
Weeping Safety Relief Valve
Symptom
Condensing Viadrus boiler not producing condensate, or condensate pipe remains dry during operation.
No Condensation / Inefficient Condensing Operation
Symptom
Radiators only partially warm or remain cold while boiler runs, flow and return pipes at boiler are hot.
Poor Circulation / Sludged System
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Boiler does not ignite, burner does not start, display shows E01 shortly after a call for heat or hot water.
|
Ignition Failure / No Flame Detection | View Details |
| E02 |
Boiler locks out with E02, burner stops, circulation pump may continue to run for a short time. Flow temperature rises rapidly before shutdown.
|
Overheat Thermostat Tripped / Safety Temperature Limiter | View Details |
| E03 |
Boiler attempts to start but shuts down with E03. Fan may run briefly. No ignition. Often occurs on room-sealed Viadrus gas boilers with flue fan.
|
Flue Gas / Air Pressure Switch Fault | View Details |
| E04 |
Boiler display shows E04 and shuts down. Often associated with low or no water in the system. Radiators are cold and pressure gauge is near zero.
|
Low Water Pressure / Water Shortage Protection | View Details |
| E05 |
Boiler shows E05 and will not start. Flow temperature on the display may read very low or very high compared to actual pipe temperature.
|
Flow Temperature Sensor (NTC) Fault | View Details |
| E06 |
Boiler locks out with E06, domestic hot water (DHW) temperature is incorrect or not displayed, burner may not fire on hot water demand.
|
DHW Temperature Sensor (NTC) Fault | View Details |
| E07 |
Boiler shows E07 and stops. Often occurs after a power surge or wiring disturbance. Some relays may click but no normal operation.
|
Control Board Communication / Internal Fault | View Details |
| E08 |
Boiler displays E08, burner stops, and the circulation pump may continue to run. Often associated with flue gas temperature issues.
|
Flue Gas Temperature Sensor Fault / Overtemperature | View Details |
| E09 |
Boiler shows E09, burner does not start, and there may be no sound from the gas valve when a call for heat is present.
|
Gas Valve Control Fault | View Details |
| E10 |
Boiler displays E10, heating does not start, and the circulation pump may not run.
|
Circulation Pump Fault / No Flow Detection | View Details |
| E11 |
Boiler shows E11, burner stops, and there may be a strong smell of flue gases or evidence of poor combustion.
|
Flame Loss During Operation | View Details |
| E12 |
Boiler displays E12, no heating or hot water. Often associated with external control or thermostat issues.
|
External Control / Room Thermostat Communication Fault | View Details |
| E13 |
Boiler shows E13, often after a power cut or wiring change. Display may be blank or show partial information.
|
Display / User Interface Board Fault | View Details |
| E14 |
Boiler displays E14, burner does not start, and there may be no response to hot water demand.
|
DHW Flow Switch / Flow Sensor Fault | View Details |
| E15 |
Boiler shows E15 and shuts down. There may be water present in the base tray or under the boiler.
|
Water Leak / Safety Float Switch Activated | View Details |
| E16 |
Boiler displays E16, heating may work intermittently, and the fan speed seems abnormal (too high or too low).
|
Fan Speed / Modulation Control Fault | View Details |
| E17 |
Boiler shows E17, no heating, and the return temperature reading is abnormal or fixed.
|
Return Temperature Sensor (NTC) Fault | View Details |
| E18 |
Boiler displays E18, burner stops, and the system pressure may be too high.
|
High System Pressure / Pressure Sensor Fault | View Details |
| E19 |
Boiler shows E19, burner does not start, and there may be no response to external demand signals.
|
OpenTherm / Digital Communication Fault | View Details |
| E20 |
Boiler displays E20, burner stops, and the flue gas analysis test mode may not function correctly.
|
Combustion Control / Gas-Air Ratio Fault | View Details |
| – |
Boiler casing or nearby walls show signs of soot deposits or black staining.
|
Incomplete Combustion / Sooting | View Details |
| – |
Boiler emits unusual smells (burning, plastic, or flue gas odour) during operation.
|
Overheating Components / Flue Gas Leakage | View Details |
| – |
Boiler frequently loses pressure, requiring regular top-ups via the filling loop.
|
Chronic Pressure Loss | View Details |
| – |
Boiler frequently trips the electrical circuit breaker or blows fuses.
|
Electrical Short / Overcurrent | View Details |
| – |
Boiler is excessively noisy during operation (rumbling, whistling, or fan roaring).
|
Mechanical Noise / Combustion Noise | View Details |
| – |
Boiler leaking water from underneath or from side panels, puddles forming below Viadrus boiler.
|
Internal Water Leak | View Details |
| – |
Boiler lockout occurs mainly in very cold weather, flue terminal or condensate pipe may be icy.
|
Frozen Condensate / Flue Obstruction | View Details |
| – |
Boiler makes loud banging or knocking noises (kettling) during operation, especially when heating up.
|
Heat Exchanger Kettling / Localised Boiling | View Details |
| – |
Boiler produces central heating but no domestic hot water on a combi Viadrus boiler.
|
No DHW Production (Combi Boiler) | View Details |
| – |
Boiler produces hot water but no central heating, even when room thermostat is calling for heat.
|
Heating Demand / Diverter Fault (Combi) or External Valve Fault | View Details |
| – |
Boiler runs but room temperature overshoots setpoint or fluctuates widely.
|
Control / Thermostat Regulation Issue | View Details |
| – |
Boiler starts but shuts down after a few seconds, radiators remain cold, no error code displayed.
|
Short Cycling / Inadequate Flow | View Details |
| – |
Boiler will not start at all, no display or lights, completely dead.
|
No Power / Electrical Supply Fault | View Details |
| – |
Boiler’s automatic air vent constantly releases water or air, causing noise and pressure fluctuations.
|
Faulty Automatic Air Vent | View Details |
| – |
Boiler’s flue gas spillage safety device (on open-flue Viadrus models) trips, shutting down the boiler.
|
Flue Spillage / Draft Failure | View Details |
| – |
Boiler’s pilot (on older Viadrus models with standing pilot) will not stay lit or goes out frequently.
|
Pilot Flame Instability | View Details |
| – |
Boiler’s safety relief valve discharges water intermittently, even when pressure seems normal.
|
Weeping Safety Relief Valve | View Details |
| – |
Condensing Viadrus boiler not producing condensate, or condensate pipe remains dry during operation.
|
No Condensation / Inefficient Condensing Operation | View Details |
| – |
Radiators only partially warm or remain cold while boiler runs, flow and return pipes at boiler are hot.
|
Poor Circulation / Sludged System | View Details |
No matching codes found
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