Troubleshooting Guide - Electronic; Troubleshooting The Electronic Ignition System - Lennox Hearth Products MLDVTCD-35NM Care And Operation Instructions Manual

LENNOX HEARTH PRODUCTS • MERIT

TROUBLESHOOTING THE ELECTRONIC IGNITION SYSTEM

Note: Before troubleshooting, be sure that the appliance main line gas shut-off valve, the gas control valve and the wall
switch are in the "ON" position.
Important: Valve system troubleshooting should only be accomplished by a qualified service technician.
SYMPTOM
1. Nothing happens when
ON/OFF switch is turned
on (pilot does not spark).
2. The main burner does
not light and the igniter
is sparking.
3. The main burner come
"ON" but then go "OFF".
4. Glass soot.
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SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • CARE AND OPERATION
®
POSSIBLE CAUSES
A. Low voltage/or bad lead
wires.
B. Damaged igniter wire.
C. Damaged pilot assembly.
D. Batteries Low
A. No fuel supply.
B. Loose sensor wire.
C. Lose wires to valve.
D. Loose wires to ignition
module.
E. Air in the gas line.
F. Low voltage.
A. Gas supply is turned
"OFF".
B. Loose wire connection on
valve or ignition module.
C. Flame does not engulf
flame sensor.
D. Obstructed vent system.
A. Improper air shutter
opening.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
CORRECTIVE ACTION
Check voltage on AC terminals of module an/or batteries. The value should be
around 2.7 to 3.2 VAC. Confirm that wire connections are secure.
Check for visible cracked casing, cuts, etc.
Check pilot assembly for visibly broken spark electrode, etc.
Check voltage on D.C. terminal of batteries. The value should be around 3.0V
Ensure that the gas supply is turned on.
Ensure sensor wire connection is secure.
Ensure black, green and orange wires connection is secure to valve.
Ensure black sensor wire (S) and black igniter wire (I) is secure to ignition module.
Purge gas line of air.
Test voltage at AC terminals of module and/or batteries. It should be around
2.7 to 3.2 VAC.
Turned gas supply to "ON".
Check wire connection.
Check location of sensor.
Check vent system for obstructions.
Check for proper air shutter openings.