Millivolt Troubleshooting - Empire Comfort Systems VFD20MS30N-1 Installation Instructions And Owner's Manual

IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning supplies, paint, paint remover, cigarette smoke,
cements and glues, new carpet or textiles, etc., create fumes. These fumes may mix with combustion air and create odors.
1. When ignitor button is pressed, there is no spark at ODS/
pilot.
a. Ignitor electrode positioned wrong - Replace ignitor.
b. Ignitor electrode broken - Replace ignitor.
c. Ignitor electrode not connected to ignitor cable - Reconnect
ignitor cable.
d. Ignitor cable pinched or wet - Free ignitor cable if pinched
by any metal or tubing. Keep ignitor cable dry.
e. Broken ignitor cable - Replace ignitor cable.
f. Bad piezo ignitor - Replace piezo ignitor.
2. When ignitor button is pressed, there is spark at ODS/pilot,
but no ignition.
a. Gas supply turned off or manual shut-off valve closed - Turn
on gas supply or open manual shut-off valve.
b. Control knob not in PILOT position - Turn gas control knob
to PILOT position.
c. Control knob not pressed in while in PILOT position - Press
in control knob while in PILOT position.
d. Air in gas lines when installed - Continue holding down control
knob. Repeat igniting operation until air is removed.
e. Depleted gas supply - Contact local gas company.
f. ODS/pilot is clogged - Clean ODS/pilot or replace ODS/pilot
assembly.
g. Gas regulator setting is not correct - Replace gas
regulator.
3. ODS/pilot lights but flame goes out when control knob is
released.
a. Control knob not fully pressed in - Press in control knob
fully.
b. Control knob not pressed in long enough - After ODS/pilot
lights, keep control knob pressed in 30 seconds.
c. Safety interlock system has been triggered (thermostat
models only) - Wait one minute for safety interlock system
to reset. Repeat ignition operation.
d. Manual shut-off valve not fully open - Fully open manual
shut-off valve.
e. Thermocouple connection loose at control valve - Hand
tighten until snug, then tighten 1/4 turn more.
f. Pilot flame not touching thermocouple, which allows
thermocouple to cool, causing pilot flame to go out. This
problem could be caused by either 1) low gas pressure
- Contact local gas company or 2) dirty or partially
clogged ODS/pilot - Clean ODS/pilot or replace ODS/pilot
assembly.
g. Thermocouple damaged - Replace thermocouple.
h. Control valve damaged - Replace control valve.
4. Main burner does not light after ODS/pilot is lit.
a. Main burner orifice clogged - Clean main burner or replace
main burner orifice.
b. Main burner orifice diameter is too small - Replace main
burner orifice.
c. Inlet gas pressure is too low - Contact local gas company.
5. Pilot burning, no gas to burner, valve knob "ON", on/off
switch "ON."
a. "On/Off" switch, wall switch, remote control or wires defective
- Check "on/off" switch and wires for proper connections.
Page 26

MILLIVOLT TROUBLESHOOTING

SYMPTOMS - POSSIBLE CAUSES AND CORRECTIONS
Place jumper wires across terminal at switch - if burner
comes on, replace defective switch. If OK, place jumper
wires across switch wires at gas valve-if burner comes on,
wires are faulty or connections are bad.
b. Thermopile may not be generating sufficient millivolts - If the
pilot flame is not close enough physically to the thermopile,
clean the ODS/pilot.
- Be sure the wire connections from the thermopile at the
gas valve terminals are tight and the thermopile is fully
inserted into the pilot bracket.
- Check the thermopile with a millivolt meter. Take the reading
at TH-TP & TP terminals of the gas valve. The meter should
read 350 millivolts minimum, while holding the valve knob
depressed in the PILOT position, with the pilot lit, and the
ON/OFF switch in the OFF position. Replace the faulty
thermopile if the reading is below the specified minimum.
- With the pilot in the ON position, disconnect the thermopile
leads from the valve. Take a reading at the thermopile leads.
The reading should be 350 millivolts minimum. Replace the
thermopile if the reading is below the minimum.
c. Defective valve - Turn valve knob to "ON." Place ON/OFF
switch to "ON." Check with millivolt meter at thermopile
terminals. Millivolt meter should read greater than 200
millivolts. If the reading is okay and the main burner does
not ignite, replace the gas valve
d. Plugged main burner orifice - Check main burner orifice for
blockage and remove.
6. Delayed ignition of main burner.
a. Manifold pressure is too low - Contact local gas company.
b. Main burner orifice clogged - Clean main burner and main
burner orifice.
7. If burning at main burner orifice occurs (a loud, roaring
blow torch noise).
a. You must turn off burner assembly and contact a qualified
service person.
b. Main burner orifice is clogged or damaged – Clean main
burner and main burner orifice or replace main burner ori-
fice.
c. Damaged main burner – Replace damaged main burner.
d. Gas regulator defective – Replace gas regulator.
8. Yellow flame in front section of main burner during main
burner combustion.
a. Not enough air - Check main burner for dirt and debris. If
found, clean main burner.
b. Gas regulator defective - replace gas regulator.
42605-3-0621