Worcester boiler error codes

The Worcester company is part of the Bosch Group. It has recently introduced a new combined gas boiler Worcester Greenstar i, which is characterized by enhanced productivity, A-class energy performance and many other useful features. And refer to the table below for Worcester boiler error codes.

Worcester Greenstar Highflow 440 boiler error codes

Display Code: Fault description: Check, repair/replace as necessary:
A5 Tank sensor fault Tank sensor (8000 – 20000 ohms at room temperature). Wiring and connections to sensor.
A6 Link fault Check link 8 to 9 in connector ST3.
A7 DHW sensor fault DHW sensor (8000 – 20000 ohms at room temperature). Wiring and connections to sensor.
A8 Module fail Night set back module TR212E and/or Roomstat TR2. Wiring and connections between modules.
b1 Code plug not detected Code plug version, condition and fitting. If OK replace control board.
C1 Fan speed too low Fan harness and connections. Fan.
Otherwise replace control board.
d3 Terminals 8-9 not shorted at connector ST7 Safety overheat thermostat for underfloor heating system (if fitted).
Otherwise fit link.
d5 Condensate pump failed Mains supply to condensate pump. Condensate Pump unit.
Continuity of all cables to pump unit.
d6 Tank overheat Tank sensor is correctly fixed to tank Wiring and connections to sensor.
E2 CH flow sensor fault CH flow sensor (8000 – 20000 ohms at room temperature).
Wiring and connections to sensor.
E9 (error solution E9) Safety overheat device tripped All air vented.
Water pressure above minimum.
Leaks or blockage.
Condition and attachment of CH flow sensor.
Pump and associated wiring/connections.
Connections and wiring to overheat thermostat devices. Otherwise replace control board.
EA Flame not detected Gas present and at correct pressure. Combustion C02 level.
Condition of flue.
Ignition electrodes.
Ignition harness and connections. Flame sense harness.
Flame sense cables and connections. Gas valve.
Otherwise replace control board.
FO Internal error Transformer.
All connections to control board. Otherwise replace control board.
F7 Flame detected with no demand. Gas valve
Flame sense electrodes/cables Moisture on control board. Blocked condensate trap. Otherwise replace control board.
FA Flame detected after gas. Gas valve switched off. Cables and connections to gas valve. Condensate trap.
Flue (for blockages).
Otherwise replace control board.
Fd Reset button pressed by mistake Press reset button again.

Worcester GREENSTAR HIGHFLOW 440CDI ERP boiler error codes

Error code Description
A7 Hot water NTC sensor defective.
A8 Break in communication to weather compensating clip-in control or Greenstar Comfort IIRF
bl Code plug not detected.
C6 Fan speed too low.
E2 CH flow NTC sensor defective.
E9 Safety temp, limiter in CH flow has tripped.
EA Flame not detected.
Check, if it safe to do so:
• if gas is on in the house
• for frozen condensate pipe
• for blocked flue outlet
FO Internal error.
F7 Flame detected even though boiler switched off.
FA Flame detected after gas shut off.
Fd Reset button pressed by mistake.

Worcester basic error codes

Locking Fault Code Possible Cause
9A Boiler has been fitted with incorrect Heat Control Module (HTM).
9U The code plug could be faulty or not properly connected.
B7 You need to replace the control board.
C6 The system is running too fast or too slow.
C7 Fan is not running or the airflow could be blocked.
D1 Sensor could be wet, damaged or disconnected. The boiler will block for 300 seconds.
D1 Boiler is overheating.
E2 The Flow sensor has shorted, is damaged or disconnected.
E5 The primary flow sensor has overheated.
E9 (error solution E9) The main heat exchanger has overheated as the main temperature is 150 degrees.
E9 (error solution E9) Maximum temperature sensor on the main heat exchanger cannot be recognised or has failed.
E9 (error solution E9) The flue gas thermostat has overheated.
EA Failure after four ignition attempts. The boiler will wait 30 seconds before another attempt is made.
EA A flame has been extinguished due to either moisture in the sump, a blocked sump or strong wind in the flue.
EA Gas valve coil has been disconnected.
EA Flame has not extinguished within first 4 seconds of ignition.
EA There is an error as the pump is not detecting water. Check the pressure gauge and re-pressurise to 1 bar.

Blocking Fault Code    Possible Cause
   A1 Little or no water in the system- Check pressure gauge and re-pressurise to 1 bar.
   C1 Fan has stopped.
   EA No flame is detected and so the boiler will block during 4 attempts before going to Locking fault.
   EF The boiler is operating at minimum burner load and there is higher flow temperature of 18 degrees.
   260 Sensor has been disconnected or there is no water content- check pressure gauge and repressurise to 1 bar.