Crown Boiler BSI172 Installation Instructions Manual page 40

Standing Pilot Ignition System Troubleshooting Chart
START
(24 VOLTS PRESENT ACROSS TH AND TR
ON GAS VALVE, BUT MAIN BURNERS DO
NOT LIGHT)
Y
Ensure knob
Pilot lit? on gas valve is
set to ON
N
Turn control on
gas valve to
PILOT. Depress
red button and
light pilot. Hold
button for at
least one
minute.
Y
Does pilot
light?
N
Line pressure
within the range
indicated on
boiler's rating
plate?
Y
*Pilot tubing
blocked, kinked
or leaking
*Pilot orifice
blocked
*Gas line not
purged of air
*Pilot improperly
adjusted.
Main
burners
light?
Turn control
on gas valve
to ON.
Y
Does pilot
stay lit when
red button is
released?
N
Consult gas
supplier.
*Defective thermocouple
*Pilot improperly
adjusted
*Pilot tube blocked, kinked, or
leaking
*Pilot orifice partially plugged
Caution: Read page 34 before
attempting to use this chart
Y
Does pilot
stay lit?
N
*Defective gas
valve
Disconnect
thermocouple from
gas valve. Connect a
volt meter to the
N
thermocouple. Light
the pilot and hold
down the red button
while reading the
voltage across the
thermocouple.
Is voltage at
least 18mV?
N
*Loose or defective
thermocouple
connection at gas valve
*Defective gas valve
40
39
Y
END
N
*Loose
thermocouple
connection at
gas valve.
*Defective
thermocouple.
*Condensation
quenching pilot.
*Low line
pressure.
Y