Worcester Bosch Oil Boiler Error Codes 2021

Worcester Bosch Oil Boiler Error Codes 2021

Worcester Error Codes


The Worcester Bosch range of Combi, Regular and System oil boilers show either an error code on the digital display or have a sequence of flashing lights to help identify the cause of any faults.

Use the table below to find out what the various error codes and flashing light sequences on Worcester Bosch oil boilers all mean.

Lockout – false flame signal

Fault Descriptione System Behaviour
Red steady on Lockout – no flame and safety time
Red 0.5 seconds on, red 0.5 seconds off
Red 0.2 seconds on, red 0.2 seconds off Lockout – maximum number of flame loss relights
Red 2.5 seconds on, orange 0.5 seconds on Lockout – fan motor failure
Red 2.5 seconds on, green 0.5 seconds on Lockout – oil valve circuit driver failure
Orange 0.5 seconds on, green 0.5 seconds on Lockout – EEPROM failure
Red 0.5 seconds, on red ⅖ seconds off Max pre-heat time exceeded
Green 0.5 seconds on, green 2.5 seconds off Pre-heating time error
Green 0.5 seconds on, red 0.5 seconds on Extraneous light – lockout after 25 seconds
Orange steady on Pre-purge the burner remains in prep-purge
After ignition burner remains in operation
When anomalies disappear the burner re-starts
Orange 0.2 seconds on, green 0.2 seconds on Control box internal error
Green 0.2 seconds on, green 0.2 seconds on Remote reset button is activated for more than 60 seconds – when anomaly appears the burner does not stop
1 Control box is supplier with heat demand
2 The pre-heater is fitted or if no pre-heater is fitted is the link fitted
3A Green 0.5 seconds on / red 0.5 seconds on before lockout
3B Fan motor or oil pump is seized
3C 230 volts to motor across blue and black motor wired
3D Approximately 35 across blue and black motor wires
4A Motor gives 50 volts a.c across black and white wires
5A Burner fires when the photocell is covered
5B Photocell voltage 3.8> in the dark and approximately 0v in the light
6A Pump pressure more than 6 bar
6B Check oil supply to the pump
6C Drive coupling broken
7A Are ignition leads and electrodes ok and set correctly
8A Does burner light or green 0.5 seconds on / red 0.5 seconds before lockout
8B Contaminated fuel filter
8C Coil lead okay
8D Solenoid coil resistance
8E After 15 seconds from motor start 25 to 30 volts
10A Is the nozzle atomising the fuel
10B Needs new nozzle
10C Check oil pipe from pump to nozzle holder
11A Flame goes out then relights
11B Boiler or flue blocked
11C Ibalance flue and snorkel test
11D Balanced flues can recirculates gases causing recycling
11E Photocell voltage 3.8 in the dark and approximately 0v in light

Worcester Bosch Error Code EA 229 or D5

If you’re seeing the error code EA 229 or D5 on your Worcester Bosch boiler, this means that the condensate pipe is frozen. This happens due to the condensate pipe running outside, however this is an issue that you could fix yourself if you feel confident enough, you can find out how in our handy guide.


Worcester Bosch Boilers

If you’re looking to replace your Worcester Bosch oil boiler with a more efficient model, visit the Boiler Guide home of Worcester Bosch to find out the benefits and costs of all the units available in their oil and gas boiler ranges.

Common Worcester Bosch Boiler Problems

There are some common Worcester Bosch boiler problems that can prevent your boiler from working properly. If your boiler isn’t operating, use our Worcester Bosch repair advice to find out the common problems and how to fix them.