HearthStone Quality Home Heating Products, Inc.
MODENA 8140 Gas-Fired Direct-Vent
24
Troubleshooting
Symptom
Possible Cause
Corrective Action
3. Pilot burning, no gas
to main burner, valve
knob in the "ON"
position, thermostat
and/or on/off/t'stat
switch in the "ON"
position.
A. Thermostat switch or wires
defective.
B. Thermopile may not be
generating sufficient voltage.
C. Plugged burner orifice.
A. Check thermostat/wiring for proper connections.
Place jumper wire across terminals at thermostat. If
burner comes on, replace defective thermostat. If not
OK, place jumper across thermostat wires at gas valve.
If burner comes on, tighten connections, or replace
faulty wires.
B. Check thermopile output, using a milli-volt meter.
Take the readings across generator terminals of the
gas valve. (TPTH and TP). Milli-volt reading should be
greater than 325 mV. If not, replace the pilot assembly.
If the meter reading is OK, but the burner does not
come on, replace the gas valve.
C. Remove and check burner orifice - clean or replace.
Note: do not use any metal cleaning device, as this
may damage the orifice.
4. Pilot and burner
come on, but go out
after some warm-up.
A. Inconsistent or insufficient
flame on thermopile.
B. Insufficient gas pressure.
C. Excessive
draft.
A. Adjust pilot flame size and assure that the flame is
aimed directly at the thermopile.
B. Check line pressure to ensure that the correct inlet
pressure is present for the type of gas being used. If
propane pressure is inconsistent, check for water
condensation at the regulator.
C. Check Restriction settings per this manual.
5. Frequent pilot outage
problem.
A. Pilot flame may be too low or
blowing, (high), causing the pilot
safety to drop out.
B. Excessive draft
A. Clean and/or adjust the pilot flame for maximum
impingement on the thermopile and thermocouple.
B. Check Restriction settings per this manual.
6. Glass fogs
(condensation)
A. A normal result of gas
combustion.
A. After the heater warms up, the glass should clear.
7. Blue Flames
A. A normal result during the first
20 minutes.
A. Flames should begin to turn more yellowish after
about 20 minutes of burning.
B. If the blue color persists; adjust the air shutter for a
proper burn.
