Wrong Signal From Pin 8-9 - Worcester ZSBR 7-28 ICS1 Service Booklet

Rectifying faults
d 3
flashing.

Wrong signal from pin 8-9.

Check
1. Jumper 8 - 9 fitted correctly?
2. B Turn ON the appliance.
B Measure voltage between Termi-
nal 4 and Terminal 8.
24 V DC?
3. Heat store NTC sensor connected to
terminals 7, 8 and 9?
4. Existing heat store thermostat con-
nected to Terminals 7, 8 and 9?
5. The PCB control board is damaged.
24
Action
↓2.
yes:
B Power OFF the appliance.
no:
B Fit jumper 8 - 9 correctly, tighten screw.
B Turn ON the appliance.
d3? ↓2.
↓3.
yes:
↓5.
no:
B Power OFF the appliance.
yes:
B Plug heat store NTC sensor connector into PCB
control board (303, page 46, Pos. 303). If lead
has no connector: replace heat store NTC sen-
sor.
B Turn ON the appliance.
d3? ↓4.
↓4.
no:
B Power OFF the appliance.
yes:
B Fix the additional bridge 8-9 in the right position
and close the screws.
B Turn ON the appliance.
d3? ↓5.
↓5.
no:
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.
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