Troubleshooting Guide - Millivolt - Lennox Hearth Products CI1500DVF Series Care And Operation Instructions Manual

TROUBLESHOOTING THE MILLIVOLT GAS CONTROL SYSTEM
Note: Before troubleshooting the gas control system, be sure external gas shut off valve (located at gas supply
inlet) is in the "ON" position.
Important: Valve system troubleshooting should only be accomplished by a qualifi ed service technician.
SYMPTOM
1. Spark igniter will not light pilot after
repeated triggering of igniter button.
2. Pilot will not stay lit after
carefully following the lighting
instructions.
3. Pilot burning, no gas to burner, Valve
knob "ON," Wall Switch "ON."
4. Frequent pilot/burner outage prob-
lem.
POSSIBLE CAUSES
A. Defective igniter
(no spark at electrode).
B. Defective or misaligned electrode at pilot
(spark at electrode).
C. Gas supply pressure errant.
D. Pilot orifi ce plugged.
A. Defective pilot generator
(thermocouple).
A. Wall switch or wires defective.
B. Thermopile may not be generating suf-
fi cient millivoltage.
C. Plugged burner orifi ce.
A. Pilot fl ame may be too low or blowing (high)
causing the pilot/valve safety to drop out.
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
CORRECTIVE ACTION
Check the gap between the electrode and pilot. It should
be between 1/8" and 3/16." If the gap is out of this
range, adjust the gap or replace the pilot.
Using a match, light pilot. If pilot lights, turn off pilot
and trigger the igniter button again. If pilot lights, an
improper gas mixture caused the bad lighting and a
longer purge period is recommended. If pilot will not
light – check gap at electrode and pilot – It should
be between 1/8" and 3/16." If the gap is out of this
range, adjust the gap or replace the pilot. (Figure 18
on page 9 ).
Check inlet gas pressure. It should be within the limits
as marked on the rating plate.
Clean or replace pilot orifi ce.
Check pilot fl ame, it must impinge on thermocouple
(Figure 18 on page 9 ). Clean and/or adjust pilot for
maximum fl ame impingement on thermocouple.
Ensure that the connection between the valve and
thermocouple are tight and secure.
Check wall switch and wires for proper connections.
Jumper wire across terminals at wall switch, if burner
comes on, replace defective wall switch. If okay, jumper
wires across wall switch wires at valve, if burner comes
on, wires are faulty or connections are bad.
Check thermopile with millivolt meter. Take reading
at thermopile terminals of gas valve. Should read
325 millivolts minimum with optional wall switch
"OFF." Replace faulty thermopile if reading is below
specifi ed minimum.
Check burner orifi ce for stoppage and remove.
Clean and/or adjust pilot fl ame for maximum fl ame
impingement on thermocouple (Figure 18 on page
9 ).
15