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27
7.10.1 FAULT FINDING TEST ‘A’: CHECKING OPERATION OF ELECTRONIC CONTROL BOARD AT
START UP
MAINS
ON FAN
REPLACE FAN
YES
NO
YES
REPLACE WIRING
OR CONNECTIONS
MAINS
ON PUMP
REPLACE
PUMP
NO
YES
YES
YES
NO
NO
A1
A
CHECK &/OR
REPLACE WIRING
AND
CONNECTIONS
MAINS
ON FAN
CONNECTOR
CN4.1 & CN4.2
ON PCB
MAINS ON
PUMP CONNECTOR
CN2.1 & CN2.2
ON PCB
FAN RUNNING
PUMP
RUNNING
GREEN LED
BLINKS
START
NO
NO
YES
REPLACE WIRING
OR CONNECTIONS
AIR FLOW
SWITCH
OFF?
REPLACE AIR
FLOW SWITCH OR
CHECK FLUE GAS
TUBE
YES
REPLACE
CONTROL BOARD
IS
THERE 0 VCC
BETWEEN TERMINALS
CN8.3 & CN8.5
ON PCB
NO
NO
YES
MADE A LINK BETWEEN BLACK &
BLACK WIRES AT BOILER
TERMINAL STRIP AND CLOSE THE
TIMER CONTACT
SWITCH ON BOILER AND
SELECT MODE TO
WINTER C/H
THERMOSTAT AT MAX.
YES
LOOSE THE PUMP
ACTING WITH A
SCREWDRIVER ON
THE IMPELLER
RESTART THE
TEST
NO
NO
NO
NO
IS ROOM
THERMOSTAT
INPUT LINKED
MADE A LINK
BETWEEN THE ROOM
THERMOSTAT INPUT
CHECK IDRAULIC
CIRCUIT
WATER
PRESSURE SWITCH
IS OK
NO
IS
THERE 24dc
BETWEEN TERMINALS
CN8.3 & CN8.5
ON PCB
REPLACE
CONTROL BOARD
YES
IS
THERE 24dc
BETWEEN TERMINALS
CN9.1 & CN9.2
ON PCB
CHECK WIRING AND
CONNECTIONS OR
WATER PRESSURE
SWITCH
MAINS
BETWEEN PIN
CN1.4 & CN1.5
ON PCB
REPLACE
CONTROL BOARD
RESTART THE
TEST
CHECK WIRING OR
CONNECTIONS
BETWEEN TERMINAL
STRIP AND CONTROL
BOARD
YES
YES
YES
YES
NO
NO
PUMP RUNNING
YES