Worcester CDi Combi N.G Service Booklet page 33

A8
and fault indicator LED are flashing.
Bus communication to the programmer interrupted (set value not received)
Check
1. B Switch off the appliance.
B Disconnect the appliance power.
B Remove the upper section of the
programmer mount and slide the
programmer out of the wall
mount.
B Check the wiring between the
programmer and the appliance.
Are terminals B being used, the cen-
tre terminal must not be used for
bus connections.
Check that terminals B are con-
nected on the appliance and pro-
grammer.
B Is there continuity
2. Where multiple bus modules are
installed:
B Check the wiring between bus
modules and the branch box.
B Ensure that the B terminals are
employed.
B Switch off the appliance.
B Disconnect the appliance power.
B Is there continuity
3. Where multiple bus modules are
installed:
B Check the wiring between branch
box and the programmer.
B Ensure that the B terminals are
employed.
B Switch off the appliance.
B Disconnect the appliance power.
B Is there continuity
4 Has the programmer been replaced?
Tab. 17 A8 Error codes
8 716 115 748 (2009/09)
Supplied By www.heating spares.co Tel. 0161 620 6677
Action
yes: A8? go to 2
no: B Wire up or correct bus cable.
B Reconnect appliance power.
B Switch on appliance.
A8? go to 2
yes: A8? go to 3
no: B Cable between bus module and branch box is
defective.
B Repair or replace cable.
B Reconnect appliance power.
B Switch on appliance.
A8? go to 3
yes: A8? go to 4
no: B Cable between the branch box and programme is
defective.
B Repair or replace cable.
B Reconnect appliance power.
B Switch on appliance.
A8? go to 4
yes: A8? go to 5
no: B Switch off appliance
B Disconnect electrical power
B Replace programmer
B Reconnect appliance power
B Switch on appliance
A8? go to 5
RECTIFYING FAULTS
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