| Problem | Possible Cause | Solution |
| The burner is not working | a) There is a loose connection in the boiler thermostat wiring. b) The fuse may have blown. c) The minimum gas pressure presostat is set to a higher value than required, or there is a loose connection in the wiring. d) There may be no neutral supply. e) There is a fault in the connections of the minimum gas pressure switch. f) The fan motor thermal cut-out may have tripped. | a) Check. b) Check. c) Set the minimum gas pressure switch to a value 3 to 4 mbar lower than required and check the connections. d) Check. e) Connect the minimum gas pressure presostat to normally open terminal blocks. f) Set the thermal cut-out current to the fan current setting. |
| The unit is performing a pre-purge, but when the main burner is due to engage, it switches to fault mode and the warning light comes on. | a) The minimum gas pressure presostat is set to a high value. b) There is air in the system. c) One of the main or safety solenoid valves may not be functioning. c-1) One of the solenoid valves may be closed. c-2) One of the main or safety solenoid valves may be blocked by debris. c-3) Power is not reaching one of the solenoid valves. d) The ignition transformer is not firing. e) The combustion air is not suitable. | a) Adjust the minimum gas pressure presostat to a value 3–4 mbar lower than the required setting. b) Bleed the air from the system via the test nipple. c) There is no power to the solenoid valves. Check that 220 V is present using a voltmeter. c-1) Set the main solenoid valve to the correct setting and ensure the safety solenoid valve is fully open. c-2) Clean the system. c-3) Check that 220 volts is present at the solenoid valve terminals. d) Check. e) Readjust by reducing or increasing the air setting. |
| The unit is performing a pre-sweep, but the main blower is not engaging at all. | a) The air pressure switch is set to a higher value than required. b) There may be a fault in the air pressure switch connections | a) Depending on the burner type, adjust the air pressure required for operation at the nominal flow rate to a value approximately 1–2 mbar lower. b) The air pressure switch connections must be made to normally open terminals |
| A pilot flame is forming in the burner, but the main flame is not forming | a) The required current is not reaching the ionisation rod. a-1) The tips of the ionisation rod are not within the pilot flame. a-2) The ionisation rod is not producing the required current. | a) Electrode position: a-1) Check by referring to the section ‘Position of the Electrodes Relative to the Turbulator’. a-2) Connect an ammeter in series with the ionisation rod circuit and measure that the current is between 15 and 100 mA. |
| The burner motor is not running | a) The motor thermal cut-out has tripped. b) The required voltage is not reaching the motor. c) It is tripping due to overheating. d) The circuit from the control unit to the motor is broken. e) The motor has burnt out. | a) Check the thermal cut-out, readjust the current setting and press the reset button. b) Check that 220 volts is present at the measurement terminals. c) Restart the system. d) Check the connection. e) Check the motor. |
