OWNER’S MANUAL MODEL: 8745 TUCSON Vent-Free HEATER
-21-
TROUBLESHOOTING
Symptom
1. Pilot will not light.
2. Pilot will not stay lit
after carefully following
lighting instruction.
3. Pilot burning, no gas
to main burner, valve
knob in the “ON”
position ,On/Off/T-stat
switch in the
“ON”position, or if “T-
stat” is selected,
Thermostat is in the
“ON” postion .
4. Pilot and burner
come on, but go out
after some warm-up.
Possible Cause
A. Insufficient gas pressure,
air in the pilot line, or dirty or
kinked gas line.
B. Pilot orifice plugged.
C. Defective or misaligned
electrode at pilot.
D. Defective ignitor.
E. After sitting for “off”
season (summer), pilot
assembly may be dirty
A. Low or too high gas
pressure
B. Faulty connections
C. Defective thermocouple.
D. Pilot dirty or plugged
A. If “T-stat” is selected,
thermostat switch or wires
defective.
B. Thermopile may not be
generating sufficient voltage.
C. Plugged burner orifice.
A. Inconsistent, of
insufficient flame on
thermopile.
B. Insufficient gas pressure.
Corrective Action
;
A. Using the piezo sparker, try to light the pilot.
If it will not light, check the inlet gas pressure.
B. Clean or replace the pilot assembly
C. If a match lights the pilot, check the electrode
gap and location. Should be a
c
" gap in the
flame area.
D. Check for a good connection between ignitor
and electrode. Check wire insulation. If properly
connected and no spark, replace ignitor.
E. Clean or replace the pilot assembly
A. Check for proper inlet pressure for the gas
being used.
B. Measure voltage between valve body and
solder connection on the rear of the valve (where
the blue wire connects). It should be no less than
7 mV.
C1. Ensure that the thermocouple connection at
the gas valve is tight.
C2. Check thermocouple output using milli-volt
meter. Disconnect from valve and read voltage
across wire ends. If the reading is less than 14
mV, replace the pilot assembly.
C3. If burning NG, check pilot flame to see that
it is impinging on the top
c
" of the
thermocouple. Clean or replace pilot for
maximum flame impingement.
D. Clean or replace the pilot assembly
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. If the optional on/off kit has not been
installed, take the readings across generator
terminals of the gas valve. (TPTH and TP). With
the on/off kit, take the readings across TH and
Terminal block(which corresponds to #3 on the
switch). Millivolt 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.
A. Adjust 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.
