Worcester Greenstar 25Si Compact Installation, Commissioning And Servicing Instructions page 71

Fault Cause
codes codes Description
F0 237 -
239
242 -
256
258 Internal error
259
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 32 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
E9 224 MAX thermostat activated
276 Flow temperature exceeds 95°C
277 Safety temperature exceeds 95°C
285 Return temperature exceeds 95°C
EA 227 No ionisation detected after ignition
EF 349 Central heating, boil detect.
Large delta T despite minimum burner.
No 212 Safety or flow temperature rises too fast
code
213 Temperature difference between supply
and return exceeding limit
260 No temperature rise after burner starts
380 Inlet DHW temperature higher than the
DHW outlet temperature.
Table 33 Blocking codes
Greenstar Si Compact ErP - 6 720 813 278 (2015/07)
Reset type Possible cause
Call Worcester, Bosch Group
Technical helpline 0330 123 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 seconds before going to Locking error ( table 32).
Blocking for 300 seconds before going to Locking error ( table 32).
The temperature of the primary flow and the safety sensor on the WB7 should be within
15°C of each other.
Flue gas thermostat overheat.
Primary overheat - boiler waits for temperature to reduce; if not it becomes a Locking
error.
Main heat exchanger safety sensor overheat - boiler will wait for the temperature to
reduce; if not it becomes a Locking error 219.
The boiler will stop the burn and wait to see if it cools down. If after 2 seconds there is an
increase in temperature the boiler will go to Locking error 286.
No flame is detected. The boiler will block during 4 attempts before going to Locking
fault.
The boiler is operating at minimum burner load and there is a greater than 18°C Flow &
Return temperature difference.
Air lock or reduced water content.
Air lock or reduced water content.
Sensor disconnected or no water content.
The output is blocked until the inlet temperature drops below the output temperature.
FAULT FINDING AND DIAGNOSIS
71