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Saunier Duval
Fault Codes
Listed below are the common Saunier Duval fault codes as described by the boiler manufacturer along with a possible cause.
Saunier Duval Ecosy Fault codes
If a fault has occurred during operation of the boiler the display will start flashing. Two numbers will alternate to show what type of fault has occurred. The second number has a decimal point after it. After correcting the fault, press the ‘reset’ button to restart the boiler.
| Fault Code = 0 and 0. | There is a flame signal without there being a flame present. Press the 'reset' button. If the fault recurs, check the ignition electrode and wire. Check to see if there is 24V a.c. on the gas valve. | If there is 24V a.c. at the gas valve then replace the Automatic control module, see section 14.4. After replacing the Automatic Control Module, press the 'reset' button and check that the boiler functions correctly. Check that flames extinguish correctly and that after heating demand is complete there is not 24V a.c. present at the gas valve. |
| Fault Code = 0 and 2. | There is no flame ionisation. This fault code may appear on commissioning the boiler and may simply due to the presence of air in the gas line. Press the 'reset' button and the ignition phase will be repeated. If the problem recurs, then proceed as follows: | Check that the gas supply to the boiler is turned on. Check that during the ignition phase there are sparks present at the electrode. Check that the spark gap of the electrode is correct, |
| Fault Codes = 0 and 3., 0 and 5., 0 and 6., 0 and 7., 1 and 1., 1 and 3., 1 and 4., 1 and 5.,1 and 6., 1 and 7., 4 and 1., 4 and 2. and 6 and 0. | There is an internal fault in the Automatic Control Module. Try pressing the 'reset' button. | If the fault is not cleared, the Automatic Control Module should be replaced. Refer to section 14.4. |
| Fault Codes = 0 and 4. | Power supply has been interrupted. This fault code may appear on first commissioning the boiler, or if the power is interrupted while the boiler is in operation. | Press the 'reset' button. If the fault code is not removed then an internal fault has occurred in the Automatic Control Module |
| Fault Code = 2 and 4. | The heating flow thermistor and heating return thermistor are connected the wrong way round. | Exchange the thermistor positions or their wiring. |
| Fault Code = 3 and 0. | There is excessive temperature difference between the flow and return thermistors. | Check that the pump is functioning correctly. Check that the system is not air locked. Check that the flow rate through the installation is high enough. |
| Fault Code = 3 and 1. | The heating flow thermistor is short circuited. | Check the wiring between the thermistor and the Automatic Control Module for a short circuit |
| Fault Code = 3 and 2. | The heating return thermistor is short circuited. | Check the wiring between the thermistor and the Automatic Control Module for a short circuit. If the wiring is sound, change the thermistor |
| Fault Code = 3 and 6. | The heating flow thermistor is too resistant. | Check that the wiring has not become disconnected If the wiring is sound, change the thermistor. |
| Fault Code = 3 and 7. | The heating return thermistor is too resistant. | Check that the wiring has not become disconnected. If the wiring is sound, change the thermistor. |
| Fault Code = 0 and 8. | The Air pressure switch has not closed. | Check that the air pressure switch is functioning correctly Check that the condense drain is not blocked and backing up into the heat exchanger. |
|---|---|---|
| Fault Code = 2 and 8. | The fan is stationary or there is no fan speed signal. | Check the wiring to the fan. Check the fan and replace as necessary. |
| Fault Code = 2 and 9. | The fan is stationary and open circuit. | Check the wiring to the fan. |
| Fault Code = 1 and 8. | The heating flow thermistor is detecting a temperature in excess of 100°C. | Check that the pump is functioning correctly. Check that the system is not air locked. Check that the flow rate through the installation is high enough. |
| Fault Code = 1 and 9. | The heating return thermistor is detecting an excessive temperature. | Check that the pump is functioning correctly. Check that the system is not air locked. Check that the flow rate through the installation is high enough. |
| Fault Code = 2 and 5. | The rate of temperature rise measured by the heating flow thermistor is too high. | Check that the pump is functioning correctly. Check that the system is not air locked. Check that the flow rate through the installation is high enough. |
13.2 Central Heating If the central heating fails to operate, or the temperature provided is poor, check the following: Check that all external controls are calling for heat. Check that the boiler controls are set correctly, see section 11. Increase temperature or return to 'Normal mode', if necessary.
If there is still a problem, check that no domestic hot water taps are dripping. A dripping tap can prevent the boiler from operating in the central heating mode. Repair any leaking taps as necessary.
Saunier Duval Isotwin Condens Fault Codes
|
Code |
Description |
Possible cause |
|---|---|---|
|
F1, F4 |
Ignition fault, boiler failed to light |
No gas / Insufficient gas Incorrect gas valve adjustment Electrode ignition lead defect Electronic igniter defective Check air inlet duct Check connections to igniter unit |
|
F5 |
Overheat fault |
Overheat stat operated Maximum temperature exceeded Check thermistor connections Air in system with thermistor at maximum setting Faulty overheat stat connection |
|
F6 |
Central heating flow thermistor fault |
Thermistor cable defective/broken Thermistor faulty Check that thermistor attached correctly to pipe |
|
F7 |
DHW thermistor fault |
Thermistor cable defective/broken Thermistor faulty Check that thermistor attached correctly to pipe |
|
F8 |
Tank thermistor fault |
Thermistor cable defective/broken Thermistor faulty Check that thermistor attached correctly to pipe |
|
F9 |
Water pressure sensor fault |
Faulty sensor connection Check wiring |
|
F10 |
Central heating return thermistor fault |
Thermistor cable defective/broken, thermistor faulty Check that thermistor attached correctly to pipe |
|
F11 |
User interface connection fault |
Check wiring between mainboard and user interface |
|
F12 |
Main board connection fault |
Check wiring between mainboard and user interface |
|
F13 |
Main board connection fault |
Check connection and wires |
|
F14 |
Central heating flow T° > 95°C |
System fault / Possible pump failure Check thermistor on flow |
|
F16 |
Flame detection fault (flame presence for more than 5 seconds after burner stopped) |
Gas valve defective |
|
F17 |
Power supply is less than 170V |
Check electrical supply / polarity |
|
F18 |
User interface fault |
Faulty user interface |
|
F19 |
Central heating thermistor unplugged |
Thermistor cable defective/broken, thermistor faulty Check that thermistor attached correctly to pipe |
|
F20 |
Software incompatibility |
Incorrect user interface or main board Incorrect product code |
|
F23 |
Water circulation fault |
Possible pump failure |
|
F26 |
Maximum delta temperature |
Water circulation fault Check central heating flow and return connection |
Saunier Duval Thema Condens Fault Codes
|
Code |
Description |
Possible cause |
|---|---|---|
|
F1, F4, |
Ignition fault, boiler failed to light |
No gas / Insufficient gas Incorrect gas valve adjustment Electrode ignition lead defect Electronic igniter defective Check air inlet duct and connections to igniter unit |
|
F5 |
Overheat fault |
Overheat stat operated Maximum temperature exceeded Check thermistor connections Air in system with thermistor at maximum setting Faulty overheat stat connection |
|
F6, F7, |
Central heating flow thermistor fault DHW thermistor fault |
Thermistor cable defective/broken Thermistor faulty Check that thermistor attached correctly to pipe |
|
F9 |
Water pressure sensor fault |
Faulty sensor connection Check wiring |
|
F10 |
Central heating return thermistor fault |
Thermistor cable defective/broken, thermistor faulty Check that thermistor attached correctly to pipe |
|
F11 |
User interface connection fault |
Check wiring between mainboard and user interface |
|
F13 |
Main board connection fault |
Main board defective Check connection and wires |
|
F16 |
Flame detection fault (flame presence for more than 5 seconds after burner stopped) | Gas valve defective |
|
F18 |
User interface fault |
Faulty user interface |
|
F19 |
Central heating thermistor unplugged |
Thermistor cable defective/broken, thermistor faulty Check that thermistor attached correctly to pipe |
|
F20 |
Software incompatibility |
Incorrect user interface or main board Incorrect product code |
|
F23 |
Water circulation fault |
Possible pump failure |
|
F26 |
Maximum delta temperature (flow - return) |
Water circulation fault Check central heating flow and return connection |
|
F28 |
Permanent drift between flow sensor and return sensor | Check central heating flow and return thermistor connection Thermistor defective |
|
F29 |
Thermal fuse |
Replace the heat exchanger |
Saunier Duval Xeon Fault Codes
|
Code |
Description |
Possible Cause |
|---|---|---|
|
F1 |
Ignition fault (lockout) Boiler failed to light | No gas,Insufficient gas, Incorrect gas valve adjustment, Electrode ignition lead defect, Electronic igniter defective, Check air inlet duct, Check connections to igniter unit |
|
F4 |
Ignition fault (lockout) Went out when lit | As F1 possible cause |
|
F5 |
Overheat fault | Overheat stat operated, Maximum temperature exceeded, Check thermistor connections,
Air in system with thermistor at maximum setting, Faulty overheat stat connection, Check that the pump is wired into appliance and not from programmer. This would cause no pump overrun. |
|
F6 |
Central heating flow thermistor fault | Thermistor cable defective or broken, thermistor faulty, Check that the thermistor is connected correctly to pipework |
|
F10 |
Central heating return thermistor fault | Thermistor cable defective/broken, thermistor faulty. Check that thermistor attached correctly to pipe |
|
F11 |
Main board connection fault | Check wiring between mainboard and user interface. |
|
F12 |
User interface connection fault | Check wiring between mainboard and user interface. |
|
F13 |
Main PCB connection fault | Check connections and wires |
|
F14 |
Central heating flow temperature is greater than
95 °C |
System fault, Possible pump failure, Check Thermistor on flow |
|
F16 |
Flame detection fault (flame presence for more than 5 seconds after burner stop) | Gas valve defective |
|
F17 |
Power supply is less than 170/V | Check electrical supply/polarity |
|
F18 |
User interface fault | Faulty User Interface |
|
F19 |
Central heating thermistor unplugged | Check thermistor connection |
|
F20 |
Software incompatibility | Incorrect user interface or Main PCB |
|
F24 |
Central heating return temperature is greater than
90 °C |
System fault, Possible pump failure, Check thermister on return line |
|
F25 |
Maximum temperature rise slope | Possible pump failure, Air in system |
|
F26 |
Maximum delta temperature | Check thermistor on return, system too restrictive. |
