Lennox Hearth L20 DVF-2 Gas Heater User Manual


 
TROUBLESHOOTING Qualified Technicians Only
(ALL MODELS)
PAGE 23
PROBLEM
CAUSE(S)
SOLUTIONS
1) Pilot will not light, and Piezo Igniter does not
produce a heavy blue spark.
a. Electrode wire (at Piezo Igniter) not pushed
completely on.
b. Piezo igniter is defective
Make sure connections are solid.
Replace piezo igniter.
2) Pilot will not light, but Piezo Igniter produces a
heavy blue spark.
a. Incorrect lighting procedure.
b. No gas to appliance due to shut valves or dis-
connected gas lines.
Carefully follow the lighting / operating in-
structions found in the appliance of this
owner's manual.
Check for multiple gas shut-offs; check gas
supply lines.
3) Pilot will not stay lit. a. Thermocouple is not firmly connected to control
valve.
b. Pilot flame is not directed to top of thermocou-
ple.
c. Thermocouple is defective. Make sure connec-
tion is solid.
Ensure thermocouple is fully inserted into pilot
assembly.
Replace thermocouple.
4) Pilot flame stays lit, but main burner will not
light.
a. Burner control switch (on control panel) is in
"OFF" position; or thermostat (if installed) is
turned off or temperature setting is too low.
b. Electrical wiring is damaged or poorly con-
nected
c. One of the following components may be de-
fective: burner control switch, thermostat, vent
spill switch, or thermopile.
Position the burner control switch to "ON"; or
adjust the thermostat. Refer to manufacturer's
instructions for thermostat.
Refer to Control and Safety Wiring Diagram
(page 22) and check electrical connections.
Refer to Control and Safety Systems Wiring
Diagram (page 22). Electrically bypass com-
ponents one at a time and replace defective
item. See page 24 for Spill Switch trouble-
shooting.
5) Main burner stays lit for up to 10 minutes and
then shuts off, pilot flame remains lit.
a. Flue / vent is blocked; flue gas is "spilling",
which activates the safety switch and shuts
down the appliance.
b. (B-Vent) The house is negatively pressurized.
Examine venting system for blockage. Re-
move any blockage.
Open a window to see if the problem is cor-
rected. See page 24 for Spill Switch trouble-
shooting.
6) Smell of gas a. Loose fittings may be allowing gas to leak out. Check all joints for leakage: pilot assembly,
gas supply system, main burner assembly, pi-
lot and burner adjustment screws. Use a
proper leak check solution. WARNING: Never
use an open flame to check for leaks.
7) A thin coating of black soot forms on the win-
dow. NOTE: See page 20, Cleaning Glass.
a. Burner primary air inlet is restricted or
blocked.
b. Flames make contact with logs or other sur-
faces.
c. Improper venting.
Be sure all openings (fresh air inlets) in stove
are free from dust and debris. Recheck these
areas periodically.
Make sure ceramic logs are in their correct
positions.
Check for flue blockage, disconnected flue,
improper installation. Make appropriate cor-
rections.
8) A white coating forms on windows, logs, and /
or inside walls of firebox.
a. Residues / impurities being burned off. Follow cleaning guidelines outlined in the
MAINTENANCE section of this manual.
9) Circulation blower makes a humming sound,
but there is no circulation air.
a. Impeller blades in circulation blower are dirty.
b. Circulation blower is defective.
Disconnect electrical power to circulation
blower, access blower and clean impeller
blades as outlined in the MAINTENANCE sec-
tion of this manual.
Replace blower.
REFERENCE INFORMATION FOR QUALIFIED TECHNICIAN:
Thermopile / Thermocouple Operation
Thermopile: Millivolt production should be a minimum of 325 MV
with pilot only.
Thermocouple: Millivolt product-ion should be a minimum of 14
MV with pilot only.
Drop out rate
TP 50-60 MV
TP 1 1/2-2 Min. (3 max.) if longer, replace thermopile.