23
Mynute 24m
7.8.3
FAULT FINDING TEST ‘C’: CHECK CONTROL IN CH MODE
NO
YES
NO
YES
YES
NO
YES
NO
REPLACE
CONTROL BOARD
REPLACE
CONTROL BOARD
REMOVE JUMPER
IS
TIMER JUMPER
ON
IS
VOLTAGE
ACROSS TERMINALS OF
MODULATOR COIL
>10 VDC
IS
VOLTAGE
ACROSS TERMINALS OF
MODULATOR COIL
< 8 VDC
CHECK BOILER
STARTUP TEST A
SET TIMER
JUMPER ON
DOES
BURNER
LIGHT
MADE A LINK BETWEEN
BLACK & BLACK WIRES AT
BOILER TERMINAL
STRIP.
SWITCH ON BOILER
AND SELECT MODE
TO WINTER C/H
THERMOSTAT AT
MAX.
START
RESTART THE
TEST
NO
NO
YES
REPLACE WIRE
AND
CONNECTIONS
REPLACE
CONTROL BOARD
REPLACE
MODULATOR COIL
IS THE
RESISTENCE OF
MODULATOR COIL
ABOUT 70/80
OHM
IS
THERE A
VOLTAGE <8 VDC
BETWEEN TERMINALS
CN9.3 & CN9.4
ON PCB
YES
C
IS
VOLTAGE
ACROSS TERMINALS OF
MODULATOR COIL
>10 VDC
SWITCH CH
THERMOSTAT AT MIN.
NO
YES
NO
WAIT TILL THE
VOLTAGE BETWEEN
TERMINAL CN9.3 & CN9.4
ON PCB IS < 1.2 Vdc
IS THE
VOLTAGE
TERMINAL CN9.3 &
CN9.4 ON PCB IS
< 1.2 Vdc
IS
D.H.W.
TEMPERATURE
>80 °C
WAIT D.H.W.
TEMPERATURE
>80 °C
YES
NO
YES
NO
IS
C.H. NTC
OK
REPLACE
C.H. NTC
REPLACE
CONTROL BOARD
YES
BETWEEN
