Benchmark ZWB 7-29 CC1 Installation And Servicing page 66

Failure identification procedure
A7
flashing.
Hot water NTC sensor defective
Check
B Unplug 20-pin connector from
4.
PCB.
After max. 60 sec.:
Does the displayed code change
to a value between 0. and 5.?
5.
1) For notes, refer to Appendix
18
Action
B Power OFF the appliance.
yes:
B Disconnect the boiler electrical connection.
B Change the 20-pin connector lead assembly.
B Reconnect the boiler electrical connection.
B Turn ON the appliance.
↓5.
B Make a note of the altered service settings (see
no:
table 1, "First Service Level; Values that can be
modified" at page 8 and table 5, "Secondary
Service Level; Values that can be modified" at
page 11).
B Power OFF the appliance.
B Disconnect the boiler electrical connection.
B Change PCB control board.
B Reconnect the boiler electrical connection.
B Turn ON the appliance.
B Restore service settings previously noted down.
↓5.
To return to normal function mode:
B Press buttons
B Regulate the temperature control
temperature control
positions.
and simultaneously.
and the
on the previously set
7 181 465 346 GB (03.02)