Benchmark ZWB 7-29 CC1 Installation And Servicing page 63

3.3 Error codes on the display
A5
flashing.
Heat store NTC sensor 2 defective
Check
1.
B Press button
B Select service function .3 .
Is a temperature between 0. and
5. displayed?
2. Heat store NTC:
B Unplug connector.
B Short circuit the connector.
Display changes to temperature
between 99. and 95.
3. Temperature between 95. and 99. is
displayed.
B Unplug connector.
After max. 60 sec.:
Does the displayed code change
to a value between 0. and 5.?
B Unplug 20-pin connector from
4.
PCB.
After max. 60 sec.:
Does the displayed code change
to a value between 0. and 5.?
7 181 465 346 GB (03.02)
yes:
.
no:
yes:
no:
yes:
no:
yes:
no:
Failure identification procedure
Action
B Note the setting of the temperature controls
and .
B Flue gas connector corroded
dirty?. Change relative parts.
↓2.
↓3.
B Power OFF the appliance.
B Change NTC sensor.
B Plug the connection wire.
B Turn ON the appliance.
A5? ↓3.
B Change the 20-pin connector lead assembly.
↓3.
B Power OFF the appliance.
B Change NTC sensor.
B Plug the connection wire.
B Turn ON the appliance.
A5? ↓4.
↓4.
B Power OFF the appliance.
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
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.
1)
, damaged or
15