Saunier Duval
Saunier Duval Boilers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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F0
The boiler displays F0 and does not start heating or producing hot water.
Flow Sensor / Flow Switch Fault
F1
The boiler shows F1 and will not ignite; no flame is established.
Ignition Failure / Flame Detection Fault
F10
Boiler displays F10 and shuts down, often associated with low system pressure.
Low Water Pressure / Pressure Sensor Fault
F11
Boiler displays F11 and locks out, often with a rapid temperature rise.
Primary Circuit Overheat / Safety Thermostat Trip
F12
Boiler displays F12 and does not respond to thermostat commands.
Room Thermostat / Communication Fault
F13
Boiler displays F13 and will not operate, often after wiring changes or accessory installation.
External Sensor / Cylinder Probe Fault
F14
Boiler displays F14 and locks out, often with no ignition attempt.
Gas Valve Control Fault
F15
Boiler displays F15 and stops, sometimes with noisy operation beforehand.
Primary Heat Exchanger Overheat / Flow Restriction
F16
Boiler displays F16 and will not start, often after PCB replacement or power issues.
Configuration / Parameter Fault
F2
The boiler displays F2 and shuts down shortly after an ignition attempt.
Flame Loss During Operation
F20
Boiler shows F20 and locks out, often with high temperature readings.
General Overheat / Safety Cut-out
F22
Boiler displays F22 and will not fire; pressure gauge often near zero.
Dry Fire / Low Water Content Protection
F23
Boiler shows F23 and stops, often with a large difference between flow and return temperatures.
Flow/Return Temperature Differential Fault
F24
Boiler displays F24 and locks out, often intermittently.
Pump Protection / Low Flow Fault
F25
Boiler shows F25 and shuts down, sometimes with signs of poor combustion.
Flue Gas Temperature / Flue Sensor Fault
F26
Boiler displays F26 and will not ignite.
Gas Valve Regulation / Modulation Fault
F27
Boiler shows F27 and locks out, sometimes with a smell of gas at the flue.
Flame Detection / False Flame Signal
F28
Boiler displays F28 and fails to ignite; multiple ignition attempts may be heard.
Ignition Lockout (No Flame Detected)
F29
Boiler shows F29 after starting then shutting down; the flame goes out during operation.
Flame Loss During Operation
F3
The boiler shows F3 and locks out; the fan does not start or runs erratically.
Fan / Air Pressure Fault
F32
Boiler displays F32 and does not start; the fan may run at an incorrect speed.
Fan Speed Control / Communication Fault
F37
Boiler displays F37 and stops; pressure fluctuates or drops.
Low System Pressure / Pressure Drop
F4
The boiler displays F4 and stops heating, often after running for a short time.
Primary Flow Temperature Sensor Fault (NTC)
F5
The boiler shows F5 and locks out, often associated with overheating or poor circulation.
Return Temperature Sensor Fault (NTC) / Overheat Detection
F6
The boiler displays F6 and will not fire for central heating or hot water.
Domestic Hot Water NTC Sensor Fault
F7
Boiler displays F7 and does not start, or stops shortly after the fan starts.
Air Pressure Switch / Flue Safety Fault
F75
Boiler displays F75 on start-up; pump runs but no pressure change is detected.
Pump / Pressure Sensor Interaction Fault
F8
Boiler displays F8 and locks out, often with no fan operation.
Fan Speed / Fan Feedback Fault
F9
Boiler displays F9 and will not operate, sometimes after a power surge or wiring work.
PCB / Internal Communication Fault
Symptom
Boiler condensate pipe dripping heavily or gurgling noises from condensate trap
Condensate Drainage Issue
Symptom
Boiler display works but no response to heating demand from room thermostat
Control Signal Not Reaching Boiler
Symptom
Boiler does not start at all; no display or lights.
No Power / Electrical Supply Fault
Symptom
Boiler emits a burning smell or plastic smell during operation
Overheating Electrical Component or Dust Burn-off
Symptom
Boiler fan runs but there is no ignition and no error code displayed
Ignition Sequence Interruption
Symptom
Boiler frequently locks out and needs manual reset, with varying fault codes over time
Intermittent Electrical or Sensor Fault
Symptom
Boiler frequently loses pressure and needs topping up.
Chronic Pressure Loss
Symptom
Boiler leaking water from underneath the casing.
Internal Water Leak
Symptom
Boiler makes loud banging or kettling noises during operation.
Kettling / Localised Boiling in Heat Exchanger
Symptom
Boiler runs but radiators do not get hot or only partially heat.
Poor Central Heating Circulation
Symptom
Boiler runs for a short time then shuts down without adequately heating the property.
Short Cycling
Symptom
Hot water temperature fluctuates or runs hot then cold.
Unstable Domestic Hot Water Temperature
Symptom
Radiators heat when only hot water is requested.
Diverter Valve Passing / Stuck
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| F0 |
The boiler displays F0 and does not start heating or producing hot water.
|
Flow Sensor / Flow Switch Fault | View Details |
| F1 |
The boiler shows F1 and will not ignite; no flame is established.
|
Ignition Failure / Flame Detection Fault | View Details |
| F10 |
Boiler displays F10 and shuts down, often associated with low system pressure.
|
Low Water Pressure / Pressure Sensor Fault | View Details |
| F11 |
Boiler displays F11 and locks out, often with a rapid temperature rise.
|
Primary Circuit Overheat / Safety Thermostat Trip | View Details |
| F12 |
Boiler displays F12 and does not respond to thermostat commands.
|
Room Thermostat / Communication Fault | View Details |
| F13 |
Boiler displays F13 and will not operate, often after wiring changes or accessory installation.
|
External Sensor / Cylinder Probe Fault | View Details |
| F14 |
Boiler displays F14 and locks out, often with no ignition attempt.
|
Gas Valve Control Fault | View Details |
| F15 |
Boiler displays F15 and stops, sometimes with noisy operation beforehand.
|
Primary Heat Exchanger Overheat / Flow Restriction | View Details |
| F16 |
Boiler displays F16 and will not start, often after PCB replacement or power issues.
|
Configuration / Parameter Fault | View Details |
| F2 |
The boiler displays F2 and shuts down shortly after an ignition attempt.
|
Flame Loss During Operation | View Details |
| F20 |
Boiler shows F20 and locks out, often with high temperature readings.
|
General Overheat / Safety Cut-out | View Details |
| F22 |
Boiler displays F22 and will not fire; pressure gauge often near zero.
|
Dry Fire / Low Water Content Protection | View Details |
| F23 |
Boiler shows F23 and stops, often with a large difference between flow and return temperatures.
|
Flow/Return Temperature Differential Fault | View Details |
| F24 |
Boiler displays F24 and locks out, often intermittently.
|
Pump Protection / Low Flow Fault | View Details |
| F25 |
Boiler shows F25 and shuts down, sometimes with signs of poor combustion.
|
Flue Gas Temperature / Flue Sensor Fault | View Details |
| F26 |
Boiler displays F26 and will not ignite.
|
Gas Valve Regulation / Modulation Fault | View Details |
| F27 |
Boiler shows F27 and locks out, sometimes with a smell of gas at the flue.
|
Flame Detection / False Flame Signal | View Details |
| F28 |
Boiler displays F28 and fails to ignite; multiple ignition attempts may be heard.
|
Ignition Lockout (No Flame Detected) | View Details |
| F29 |
Boiler shows F29 after starting then shutting down; the flame goes out during operation.
|
Flame Loss During Operation | View Details |
| F3 |
The boiler shows F3 and locks out; the fan does not start or runs erratically.
|
Fan / Air Pressure Fault | View Details |
| F32 |
Boiler displays F32 and does not start; the fan may run at an incorrect speed.
|
Fan Speed Control / Communication Fault | View Details |
| F37 |
Boiler displays F37 and stops; pressure fluctuates or drops.
|
Low System Pressure / Pressure Drop | View Details |
| F4 |
The boiler displays F4 and stops heating, often after running for a short time.
|
Primary Flow Temperature Sensor Fault (NTC) | View Details |
| F5 |
The boiler shows F5 and locks out, often associated with overheating or poor circulation.
|
Return Temperature Sensor Fault (NTC) / Overheat Detection | View Details |
| F6 |
The boiler displays F6 and will not fire for central heating or hot water.
|
Domestic Hot Water NTC Sensor Fault | View Details |
| F7 |
Boiler displays F7 and does not start, or stops shortly after the fan starts.
|
Air Pressure Switch / Flue Safety Fault | View Details |
| F75 |
Boiler displays F75 on start-up; pump runs but no pressure change is detected.
|
Pump / Pressure Sensor Interaction Fault | View Details |
| F8 |
Boiler displays F8 and locks out, often with no fan operation.
|
Fan Speed / Fan Feedback Fault | View Details |
| F9 |
Boiler displays F9 and will not operate, sometimes after a power surge or wiring work.
|
PCB / Internal Communication Fault | View Details |
| – |
Boiler condensate pipe dripping heavily or gurgling noises from condensate trap
|
Condensate Drainage Issue | View Details |
| – |
Boiler display works but no response to heating demand from room thermostat
|
Control Signal Not Reaching Boiler | View Details |
| – |
Boiler does not start at all; no display or lights.
|
No Power / Electrical Supply Fault | View Details |
| – |
Boiler emits a burning smell or plastic smell during operation
|
Overheating Electrical Component or Dust Burn-off | View Details |
| – |
Boiler fan runs but there is no ignition and no error code displayed
|
Ignition Sequence Interruption | View Details |
| – |
Boiler frequently locks out and needs manual reset, with varying fault codes over time
|
Intermittent Electrical or Sensor Fault | View Details |
| – |
Boiler frequently loses pressure and needs topping up.
|
Chronic Pressure Loss | View Details |
| – |
Boiler leaking water from underneath the casing.
|
Internal Water Leak | View Details |
| – |
Boiler makes loud banging or kettling noises during operation.
|
Kettling / Localised Boiling in Heat Exchanger | View Details |
| – |
Boiler runs but radiators do not get hot or only partially heat.
|
Poor Central Heating Circulation | View Details |
| – |
Boiler runs for a short time then shuts down without adequately heating the property.
|
Short Cycling | View Details |
| – |
Hot water temperature fluctuates or runs hot then cold.
|
Unstable Domestic Hot Water Temperature | View Details |
| – |
Radiators heat when only hot water is requested.
|
Diverter Valve Passing / Stuck | View Details |
No matching codes found
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