OWNER’S MANUAL Model # 8890 DVI-Ht
Page 27 of 32
Symptom
Possible Cause
Corrective Action
3. Pilot burning, no gas to
main burner, and valve
knob in the "ON" position,
thermostat and/or
on/off/t'stat switch in the
"ON" position.
A. Thermostat switch or
wires defective.
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. Thermopile may not be
generating sufficient
voltage.
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). 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. Plugged burner orifice.
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, of
insufficient flame on
thermopile.
A. Adjust pilot flame size and assure that the flame is
aimed directly at the thermopile.
B. Insufficient gas pressure. 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.
5. Frequent pilot outage
problem.
A. Pilot flame may be too
low or blowing, (high),
causing the pilot safety to
drop out.
A. Clean and/or adjust the pilot flame for maximum
impingement on the thermopile and thermocouple.
6. Glass fogs
A. A normal result of gas
combustion.
A. After the heater has warmed 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 20
minutes of burning.
B. If the blue color stays; adjust the air shutter for a
proper burn.
