Operation
900738-00 04/2017
Innovative Hearth Products
MHD35 Series Direct-Vent Gas Fireplaces
68
TROUBLESHOOTING
Before troubleshooting, ensure that the fi replace main line gas shutoff valve and the wall switch are in the ON position. The following
troubleshoots the fi replace only to an elementary level. For detailed remote and ignition system troubleshooting, refer to the
instructions provided with the remote.
Detailed valve system troubleshooting should only be performed by a qualifi ed service technician.
Table 51 - Troubleshooting Millivolt Systems
SYMPTOM
POSSIBLE CAUSES
CORRECTIVE ACTION
1.
Spark igniter will
not light pilot after
repeated triggering of
igniter button.
WARNING: if the
pilot will not light
after 1 minute of
attempting, wait for
at least 5 minutes for
gas to clear before
attempting again.
a.
Defective igniter (no spark at electrode).
Check for spark at electrode and pilot; if no spark and
electrode wire is properly connected, replace igniter.
b.
Defective or misaligned electrode at pilot
(spark at electrode).
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 – should
be 1/8” to have a strong spark. If gap measures 1/8”,
replace pilot.
c.
Gas supply pressure errant.
Check inlet gas pressure. It should be within the limits
as marked on the rating plate.
d.
Pilot orifi ce plugged.
Clean or replace pilot orifi ce.
2.
Pilot will not stay
lit after carefully
following the lighting
instructions.
a.
Defective pilot generator (thermocouple).
Check pilot fl ame, it must impinge on thermocouple.
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.
3.
Pilot burning, no
gas to burner, Valve
knob “ON,” and the
(standard) burner
OFF/ON switch is ON.
NOTE:
If an optional*
remote switch is used
for burner operation,
if the standard burner
OFF/ON switch is still
installed on fi replace
it must be in the OFF
position.
a.
Wall switch or wires defective.
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.
b.
Thermopile may not be generating
suffi cient millivolts.
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.
c.
Plugged burner orifi ce.
Check burner orifi ce for blockage and remove.
d.
OFF/ON Switch and *Remote Switch are
in the “ON” position resulting in excessive
resistance.
When turning on the burner using a *remote switch,
ensure that the standard OFF/ON switch is in the OFF
position. If both switches are in the ON position,
it may result in excessive resistance (and millivolt
drainage) and the burner may not come on.
4.
Frequent pilot/burner
outage problem.
a.
Pilot fl ame may be too low or blowing
(high) causing the pilot/valve safety to
drop out.
Clean and/or adjust pilot fl ame for maximum fl ame
impingement on thermocouple
* Optional remote switch kits—wall switch, wall thermostat or remote control.
