Worcester CDi Combi N.G Service Booklet page 30

RECTIFYING FAULTS
A5
and fault indicator LED are flashing. Appliance still available for heating demands.
Tank (Heat Bank) NTC sensor defective.
Check
1. Is the tank NTC sensor connection
corroded, damaged or dirty?
2. B Power OFF the appliance.
B Disconnect the appliance electrical
connection.
B Unplug the 20 pin connector from
the PCB.
B Check the resistance across
connections 5 and 6 on the cable
side.
Does the value match the one in
table 43?
3. B Unplug the NTC sensor from the
cable.
B Check the resistance of the NTC
sensor.
Does the value match the one in
table 43?
Tab. 14 A5 Error codes
30
Supplied By www.heating spares.co Tel. 0161 620 6677
Action
yes: Change relevant parts
A5? go to 2
no: go to 2
yes: B Reconnect the appliance electrical connections.
B Turn ON the appliance
B Make a note of the altered service function settings.
B Power OFF the appliance.
B Disconnect the appliance electrical connections.
B Change the PCB control board.
B Reconnect the appliance.
B Turn the appliance ON.
B Restore the service setting noted previously.
no: go to 3
yes: B Change the 20 pin connector lead assembly.
B Reconnect the appliance.
B Turn the appliance ON.
no: B Change the NTC sensor.
B Reconnect the appliance.
B Turn the appliance ON.
8 716 115 748 (2009/09)