Worcester Greenstar CDi Compact Installation, Commissioning And Servicing Instructions page 69

Fault Cause
code code Description
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 22 Blocking codes
6 720 803 800 (2012/11)
Possible cause
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
69