Worcester Greenstar CDi Compact Installation, Commissioning And Servicing Instructions page 68

FAULT FINDING AND DIAGNOSIS
Cause
Fault codes codes Description
F0 237 Internal error
238 Gas valve error
239
242 - 256
258
259 Internal error
262
263
267
272
279
290
278 Sensor test failed
280 Recycle time error
338 Too many short burner starts
without confirmation
F7 228 Flame error
328 Internal error
FA 306 False flame error
FD 231 Mains power error
FA 364 Gas valve EV2 leak test failed
Fb 365 Gas valve EV1 leak test failed
Table 21 Locking fault and cause code listing
BLOCKING ERRORS
Fault Cause
code code Description
A1 281 Pump stuck or running in air
C1 264 Airflow stopped during operation
C4 273 Airflow present during last 24 hours
D1 240 Return sensor short circuit
241 Return sensor disconnected
D4 271 Temperature difference between flow and
safety sensors exceeds limit
Table 22 Blocking codes
68
Reset type Possible cause
Call Worcester, Bosch Group
Technical helpline 0844 892 3366
Reset button Leaking gas valve
Call Worcester, Bosch Group
Technical helpline 0844 892 3366
Reset button On power up all safety sensors are checked.
Check has failed.
Reset button After the burner has stopped, the recycle mode purges gas from the
heat exchanger before attempting to burn again. The software has 3.1
seconds to intervene before the boiler goes into this fault condition.
Reset button There is an error where the pump is not detecting water.
Reset button False flame. Flame detected before burner start.
Replace control board
Reset button Flame detected after burner stop
Reset button Electrical power interruption.
Reset button Gas valve leak.
Reset button Gas valve leak.
Possible cause
Little or no water in the system.
Fan has stopped.
Fan has been running continuously during the past 24 hours.
Wet sensor.
Blocking for 300 secs before going to Locking error ( table 21).
Blocking for 300 secs before going to Locking error ( table 21).
The temperature of the primary flow and the safety sensor on the WB7 should
be within 15°C of each other.
6 720 803 800 (2012/11)