Blocking Errors - Worcester 27i System Compact Installation, Commissioning And Servicing Instructions

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 20 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 21 Blocking codes
Greenstar i System Compact - 6 720 807 726 (2013/05)
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 seconds before going to Locking error ( table 20).
Blocking for 300 seconds before going to Locking error ( table 20).
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
65