Worcester Greenstar 4000 24S Lpg Boiler Fault Codes

Operating message, is not a fault.

• Heating circuit is being heated.

Operating message, is not a fault.

• Hot water circuit is being heated.

Operating message, is not a fault.

• Anti-cycle mode - this is the standby time between heating demands - default 5 minutes.

– For example, if there is heating demand for 1 minute, the boiler will wait for 4 minutes after the heating demand before firing for a subsequent heating demand. Fault code 202 will be present during anti-cycle mode.

Operating message, is not a fault.

• Appliance in standby, awaiting a demand request.

Operating message, is not a fault.

• System waiting. The actual boiler water temperature is higher than the target boiler water temperature. The boiler heat demand is switched off.

Operating message, is not a fault.

• Chimney sweep mode active.

▶ Check the plug on the fan.

▶ Check the connecting lead to the fan.

224

224

B

V

Maximal flue gas thermostat or heat exchanger maximal thermostat has activated

Maximal flue gas thermostat or heat exchanger maximal thermostat has activated

If the blocking fault persists for a prolonged period, it becomes a locking fault.

▶ Check if the lead is disconnected from the safety temperature limiter/thermostat or the flue thermostat.

▶ Check the high limit of the safety temperature limiter/thermostat or the flue thermostat and the harness for continuity.

▶ Check the flow temperature to confirm actual temperature (may have tripped out at lower temperature, leading to a safety temperature limiter/thermostat or the flue thermostat fault).

▶ Check the system pressure and top up as required.

▶ Check if air is trapped in the system and in the boiler.

▶ Pump seized/not running: check the pump for failure or blockage.

▶ Check if a blockage/restriction within boiler/pipework is restricting the flow

Tip: Check the ceramic insulator is not damaged, this can cause the spark to earth, twist and pull the ceramic insulator to ensure it is not broken.

▶ Check the gas supply to the property and the inlet on the gas valve.

▶ Check for low pressure when the gas valve opens.

▶ Gas valve failing to open: check for voltage to the valve and for possible blockage on inlet filter of the gas valve.

▶ Obstruction in the air intake to the fan leading to incorrect CO2 ratio.

▶ Condensate siphon is blocked or restricted. Condensate pipe is frozen.

▶ Flue is blocked or restricted.

▶ Heat exchanger is blocked or restricted.

▶ Check the burner for damage.

▶ Check the spark electrode/lead for failure.

▶ Check the flame sense/lead for failure.

▶ Check the rectification ground (black wire to heat exchanger).

Tip: Check the ceramic insulator is not damaged, this can cause the spark to earth, twist and pull the ceramic insulator to ensure it is not broken.

▶ Check the flame sense and the lead and replace if required.

▶ Check the earth tags on the boiler and on the electrodes.

▶ Check the operation of the siphon and that no water is collecting in the sump.

▶ Replace the gas valve.

▶ Replace the control unit and/or burner control unit.

External cut off switch not used in UK:

▶ Ensure nothing is plugged into red I3 connection.

▶ Wrong code plug is inserted.

▶ Check the code plug is not damaged.

▶ Replace the code plug if required.

▶ Check the gas supply to the property and the inlet on the gas valve (check drop on inlet).

▶ Check the connections on the gas valve and the board (loose connection).

▶ Check the continuity down harness and replace if required.

▶ Check the voltage to the gas valve (19‒24 V DC approx. when demand).

▶ Check for water on the gas valve connections.

▶ Check the resistance on the gas valve (pins 1‒2 approx. 69.5 Ohms).

▶ Replace the gas valve if resistances are incorrect.

▶ If all tests are correct: replace the PCB.

▶ Check the code plug is not damaged.

▶ Replace the code plug if required.

▶ Replace the control unit (PCB).

▶ Check the gas supply to the property and the inlet on the gas valve (check drop on inlet).

▶ Check the connections on the gas valve and the board (loose connection).

▶ Check the continuity down harness and replace if required.

▶ Check the voltage to the gas valve (19‒24 V DC approx. when demand).

▶ Check for water on the gas valve connections.

▶ Check the resistance on the gas valve (pins 1‒2 approx. 69.5 Ohms).

▶ If all tests are correct: replace the PCB.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

Operating message, is not a fault.

• The boiler's ignition sequence alone is sufficient enough to maintain room temperature.

• The modulating heat demand is higher than the minimum modulation factor of the unit. The unit switches to proportional control.

Operating message, is not a fault.

• Appliance in component test mode

▶ Restart the appliance to see if the problem re-occurs.

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit (PCB).

Operating message, is not a fault.

• The burner and fan have been running continuously for 24 hours and have been shut down briefly for an appliance electronic inspection

▶ Check primary system water pressure.

▶ Check for air in the system and vent the pump.

▶ Check for circulation within heating system.

▶ Check hydraulic connections to the pump.

▶ Check wiring and operation of the pump, replace if necessary.

Operating message, is not a fault.

• Burner is starting.

Operating message, is not a fault.

• Gas valve is opening.

Operating message, is not a fault.

• Anti-cycle mode, domestic hot water post-heat function. Following a domestic hot water demand the boiler runs for 30 seconds or until the target temperature is met.

– Diverter valve is held in the hot water position for a period of time.

– If no domestic hot water demand is requested then check for false demands on the cold water inlet.

▶ Check the gas valve, replace if required.

▶ Check electrodes and connecting leads, replace if required.

▶ Replace the appliance electronics.

Test non-volatile lockout

Operating message, is not a fault.

• If the boiler has been operating for 24 hours without a 20-minute off period, the boiler will not respond for a period of time whilst it undertakes diagnostics checks on the fan.

Operating message, is not a fault.

• Venting/air purge program has been automatically activated.

Operating message, is not a fault.

• Blocking protection for the heating pump and diverter valve active.

– The purpose of component kick is to ensure that hydraulic components such as pumps will not get stuck by giving these functional components a “kick”, i.e. they are briefly turned on after a period of inactivity.

– After power up every 24 hours the appliance will do a component kick, where the pump will run for 10 seconds.

– If the appliance is already in a CH or DHW heat request, these heat demands will be prioritised over component kick. But once the heat demand has ended the component kick will take place.

– If this causes nuisance then please power the appliance off and on again at a more suitable time; the daily kick will then occur at the time the appliance is turned on again.

▶ Wrong code plug is inserted.

▶ Check the code plug is not damaged.

▶ Replace the code plug if required.

Is not a fault.

• Service plug detected.

▶ Check and replace the ionisation cable.

▶ Check and replace the electrodes if required.

▶ Check and replace the control unit and/or burner control unit.

▶ Reset the appliance and wait 24 hours

▶ Check the DHW valves,

▶ Check the 3-way valve, replace if necessary,

▶ Check that the tank is properly connected.

▶ If water is being drawn constantly, take action to stop this.

▶ Position the DHW temperature sensor correctly.

▶ Check that there is contact between the DHW cylinder temperature sensor and the cylinder.

▶ Vent the cylinder circuit.

▶ Set DHW heating to "priority".

▶ Check plate heat exchanger for calcification.

▶ Check sizing of DHW circulation line and heat loss.

▶ Check the grey ribbon on far right of the PCB (low voltage connection).

▶ If using a Key control product check the Key connections (black, white, red, green) are plugged into the correct position on the PCB (under installer cover on the far right hand side, leaving one space to the BUS connection).

▶ Check that the Key is pushed fully home.

▶ Check the batteries of the room control.

▶ Check the bridging links are fitted at LR & 230 V out.

▶ For wired room controls check the EMS BUS Voltage to the remote control is 12 - 15V DC.

▶ Check the 230 V external wiring does not run alongside the BUS connections, thus causing interference.

▶ Replace the control unit

The service reminder message is present due to the maximum burner hours service threshold being reached.

▶ Carry out maintenance.

▶ Reset the maintenance code via the reset menu.

▶ Top up system water and vent the system.

▶ Check the voltage to the pressure sensor and the signal back from the pressure sensor.

▶ Replace the pressure sensor.

▶ Carry out maintenance.

▶ Reset the maintenance code via the reset menu

▶ Pump communication failure or wrong pump is fitted (i.e. non-ErP).

▶ Check the pump communication wire is connected and has continuity.

▶ Replace the pump for correct modulating pump.

A 1021 error can only be cleared by powering the appliance off and back on again the hot water sensor has been changed if open or short circuit, or refitted to the pipe if it has fallen off.

▶ Check the domestic hot water temperature sensor is connected and the harness is fitted securely to the sensor.

▶ Check the resistance of the temperature sensor and replace if required.

▶ Check the continuity of harness and replace if required.

▶ Connect the plug to the temperature sensor correctly.

▶ Connect the plug to the control device correctly.

▶ Check the temperature sensor, replace if necessary.

▶ Check temperature sensor connecting lead, replace if necessary.

The service reminder message is present due to the maximum run time (boiler hours) being reached.

▶ Carry out maintenance.

▶ Reset the maintenance code via the reset menu.

Tip: Check the weather compensation is applicable and the menu has not been accidentally switched on in the menu.

▶ Check the positioning of the outside weather sensor.

▶ Check the weather sensor connections on the control board.

▶ Check the plug is connected correctly to the pressure sensor.

▶ Check pressure sensor connecting leads for breaks or short circuits, replace if necessary.

▶ Check the pressure sensor, replace if necessary.

▶ Check the plug to the temperature sensor, connect correctly.

▶ Check connecting lead for break or short circuit, replace if required.

▶ Check temperature sensor, replace if necessary.

▶ Check appliance electronics, replace control unit if necessary

Advanced service reminder warning. ▶ Check the maintenance menu.

▶ Reset the maintenance code via the reset menu.

▶ Check the maintenance menu.

▶ Reset the maintenance code via the reset menu.

▶ Check the maintenance menu.

▶ Reset the maintenance code via the reset menu.

▶ Check the flow temperature sensor plug is connected.

▶ Check the resistance of the flow temperature sensor and replace if required.

▶ Check the continuity of harness and replace if required.

▶ Replace the flow temperature sensor.

▶ Check the flow temperature sensor plug is connected.

▶ Check the resistance of the flow temperature sensor and replace if required.

▶ Check the continuity of harness and replace if required.

▶ Replace the flow temperature sensor.

▶ Replace the PCB.

▶ Check the flow temperature sensor plug is connected.

▶ Check the resistance of the flow temperature sensor and replace if required.

▶ Check the continuity of harness and replace if required.

▶ Replace the flow temperature sensor.

▶ Replace the PCB.

▶ Check the flow temperature sensor plug is connected.

▶ Check the resistance of the flow temperature sensor and replace if required.

▶ Check the continuity of harness and replace if required.

▶ Replace the flow temperature sensor.

▶ Replace the PCB.

▶ Reset the appliance.

▶ Switch off the appliance for 30 seconds and then turn back on.

▶ Check the incoming mains voltage.

▶ Check the polarity.

▶ Replace the PCB.

▶ Restart the appliance to see if the problem re-occurs.

▶ If the fault remains after resetting: the burner controller (PCB) is defective and must be replaced.

▶ Check the flue for obstructions and remove any found.

▶ Check the flue integrity test.

▶ Check for water in the sump and check the siphon operation, clean if required.

▶ Restart the appliance to see if the problem re-occurs.

▶ If the fault remains after resetting: the burner controller (PCB) is defective and must be replaced.

The fan keeps running after the post purge.

▶ Reset the appliance.

▶ Create a heat demand to test the boiler's ignition sequence.

▶ Check the voltage to the fan and the continuity of the fan harness.

▶ Check the power modulation on the fan.

▶ PCB may be defective.

Gas valve was detected as open during post-purge.

▶ Carry out a gas tightness test on the gas valve and replace if required.

▶ Check the voltage to gas valve.

▶ The gas valve or the PCB may be defective

▶ Check electrodes and connecting leads, replace if required.

▶ Check protective earth conductor connections (PE).

▶ Check appliance electronics, replace control unit if necessary.

Unexpected feedback from the modulating/current controlled gas valve.

▶ Check the voltage to the gas valve.

▶ Check the continuity of harness and replace if required.

▶ Check the resistance of the gas valve coils.

▶ The gas valve or the appliance electronics (control unit) may have a fault

No ionisation detected after ignition.

▶ Check the main shut-off valve, open if necessary.

▶ Check the appliance isolation valve, open if necessary.

▶ Measure the gas supply pressure at the rated heat input. If necessary, shut down the appliance and check the gas line.

▶ Check flame sense electrode and connecting lead, replace if required.

▶ Check venturi/injector for potential blockage.

▶ Measure the ionisation current.

▶ Check the protective earth conductor connection (PE) in the control unit.

▶ Check the ignition cable for damage, replace if necessary.

▶ Check functionality of gas valve and replace if necessary.

▶ Check CO2 settings at min and max output

▶ Check flue system.

▶ Check combustion air supply.

▶ Check the heat exchanger on the flue gas side for deposits, clean if necessary.

▶ Restart appliance.

▶ If the fault persists following a reset, the burner control unit is faulty and must be replaced, (replace control unit).

Illegal instruction.

▶ Restart appliance.

▶ If the fault persists following a reset, the burner control unit is faulty and must be replaced, (replace control unit).

Low voltage.

▶ Restart appliance.

▶ If the fault persists following a reset, the burner control unit is faulty and must be replaced, (replace control unit).

Burner starts automatically after purging. This can be caused by strong winds. If this fault occurs frequently:

▶ Check CO2 settings.

▶ Check flue outlet position for effects of excessive wind pressure.

▶ Check flue integrity.

May be caused by strong winds or flue gas recirculation. The burner starts automatically after purging.

▶ Check the flue integrity.

▶ Check the flue terminal position.

▶ Check the CO2 settings and adjust if necessary.

▶ Check the burner and the heat exchanger gaskets and the inner flue gaskets.

▶ Check the gas pressure during burning at full load (working pressure, dropping low).

▶ Check gas pressure whilst burning at full load.

▶ Check CO2 settings, adjust if necessary.

▶ Check Burner and heat exchanger gaskets.

▶ Burner restarts automatically after purging.

Maximum unexpected flame losses exceeded.

▶ Refer to the blocking error(s) that lead to this locking error. Check the fault history on appliance.

▶ Possible incomplete purging of gas pipe.

▶ Could also indicate a wide variety of issues such as undersized pipework or gas pressure dropping off, incorrectly routed condensate discharge, incorrectly sited flues, incorrectly wired etc.

▶ Perform reset.

▶ If fault persists, replace control unit.

▶ Reset appliance electronics (factory reset).

▶ Check the electrical connections on the board (check for loose wires etc.).

▶ Replace the control unit.

▶ Check the mains voltage to the fan.

▶ Check the fan harness for continuity and replace if required.

▶ Check the pulse width modulation (PWM).

▶ Replace the fan.

▶ Replace the PCB.

▶ Check the mains voltage to the fan.

▶ Check the fan harness for continuity and replace if required.

▶ Check the pulse width modulation (PWM).

▶ Replace the fan.

▶ Replace the PCB.

▶ Check the flow through the appliance and the system is filled.

▶ Check for air locks in the system and purge if required.

▶ Check the heat exchanger sensor (primary thermistor) and the plug connected to temperature sensor.

▶ Check the resistance of the temperature sensor and replace if required.

▶ Check the continuity of the temperature sensor harness and replace if required.

▶ Check the flow through the appliance and that the system is filled.

▶ Check for air locks in the system and purge if required.

▶ Check the heat exchanger sensor (primary thermistor) and the plug connected to the temperature sensor.

▶ Check the resistance of the temperature sensor and replace if required.

▶ Check the continuity of the harness and replace if required.

▶ System is not filled with water.

▶ No water flow, because CH system is closed.

▶ No water flow, because pump is not operating correctly.

▶ Check flow through appliance and system pressure.

▶ Check for air locks in the system. Purge if required.

▶ Check isolation valves.

▶ System is not filled with water.

▶ No water flow, because CH system is closed.

▶ No water flow, because pump is not operating correctly.

▶ Check pump is operating freely check voltage to pump.

▶ Check the isolation valves.

▶ Check for air locks in the system, purge if required.

▶ Check flow through appliance and system pressure.

▶ Check the flow through the appliance and that the system is filled.

▶ Check for air locks in the system and purge if required.

▶ Check the isolation valves, ensure they are open.

▶ Check the pump is operating freely and check the voltage to the pump.

▶ Check the heat exchanger sensor and the flow sensor are making correct contact with the heat exchanger assembly/pipework.

▶ Check the heat exchanger sensor for break or short circuit, replace if required.

▶ Check the resistance of the supply sensor for break or short circuit, replace if required.

▶ Check the continuity of harness, replace if required.

Too many unexpected pressure drops within a short time period. Cause code can appear if system is pressurised and the system then vented.

▶ Re-pressurise manually and vent the system.

▶ Ensure the correct pressure. If cause code does not clear, power off appliance.

System pressure is very or extremely low. This is triggered when the pressure falls to between 0.6 and 0.3 bar. Top up water until the target pressure is reached.

Filling Loop

▶ Vent the heating system and top up water until the pre-set pressure reached.

Pressure sensor

▶ Check the continuity down harness for the pressure sensor and replace if required.

▶ Check the voltage at the pressure sensor and replace if required.

▶ Establish supply voltage of at least 196 VAC.

▶ Replace control unit.

Comfort + II RF

▶ Check the configuration (address setting). The selected setting requires a hard-wired room control.

▶ Check the EMS connection cable of the room control for damage. The BUS voltage on the room control must be between 12 and 15 V DC.

▶ Disconnect the EMS-BUS connection to the control unit and power the boiler off and back on again. Reconnect the EMS-BUS connection.

▶ If the problem persists the room control may be defective.

▶ Check the gas type.

▶ Check the gas supply pressure.

▶ Check the flue system; clean or repair if required.

▶ Check the gas/air ratio.

▶ Check the gas valve; replace if required

▶ Check the gas type.

▶ Check the gas supply pressure.

▶ Check the flue system; clean, repair or replace if required.

▶ Check the gas/air ratio.

▶ Check the gas valve; replace if required.

▶ Check the ignition transformer function for misfiring in the Function check menu Ignition test, replace if required.

▶ Check the gas type.

▶ Check the gas supply pressure.

▶ Check the power supply.

▶ Check the electrodes with cable; replace if required.

▶ Check the flue system; clean or repair if required.

▶ Check the gas/air ratio.

▶ For natural gas: check the external gas flow monitor, replace if required.

▶ Check the burner, replace if required.

▶ Check the air/gas ratio control valve; replace if required.

▶ Check the electrical wiring for damage.

▶ Replace defective cables.

▶ Check the fuse, replace if required. One spare fuse is supplied.