Q314, Q324, Q327, Q350, Q377, Q379, Q380 AND Q382 PILOT BURNERS
60-2075—3
21
Ignite Pilot Burner
1. Before lighting the pilot burner, turn the thermostat to its
lowest setting. Wait for unburned gas to vent.
NOTE:
LP gas is heavier than air and will not vent
upward. Smell for LP gas next to floor. If you
smell gas, shut off the main valve in the gas
piping or ON LP, at the tank. Perform Gas Leak
Test to recheck the connections.
2. Light the pilot burner according to the appliance
manufacturer instructions.
SERVICE
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE, SEVERE
INJURY, OR DEATH
Perform Gas Leak Test anytime work is done to the
system.
Pilot Outage
1. If the pilot flame goes out during normal operation, but
is properly adjusted, recheck Location instructions in
the Installation section.
2. If all Location instructions are followed but pilot flame
continues to go out, construct shielding to protect the
pilot flame from the main burner ignition and extinction
and drafts. See Fig. 25.
TYPICAL
SHIELD
M3303.AI
Fig. 25. Proper shielding of pilot flame (Q350 shown).
Pilotstat
®
Safety Control Power Unit Failure
1. Make sure the pilot flame is properly adjusted.
2. Make sure the power unit connections are clean and
tight.
3. Make sure the terminal connections are clean and tight.
4. If the power unit still fails to hold in, use the W129A
Millivoltmeter to obtain the open and closed circuit
voltage generated by the thermocouple or thermopile.
5. Compare the measured open and closed circuit voltage
values to Acceptable Range Charts in the W129A
Manual.
6. If a W129A Millivoltmeter or other meter is not available,
replace the thermocouple of thermopile. If this does not
correct the condition, replace the power unit.
Thermocouple Or Thermopile Performance
Thermocouples and thermopiles require proper temperature
differential between the hot-junction (tip) and cold-junction
(base) to provide satisfactory operation of millivoltage gas
controls. Thermocouples and thermopiles perform less
effectively when exposed to excessive cold-junction or hot-
junction temperatures.
Excessive cold-junction temperatures can be caused by heat
radiation from adjacent surfaces or high ambient air
temperatures. Excessive cold-junction temperatures can be
eliminated by shielding the pilot flame, see Fig. 25, or
constructing a baffle to direct secondary air over the pilot
burner base.
Excessive hot-junction temperatures can be eliminated by
proper pilot flame adjustment. To adjust pilot flame, see the
instructions in the Startup and Checkout section.
Pilot Turndown Test (30 mV Pilotstat® Safety
Control Systems)
The Pilot Turndown Test assures that the pilot flame ignites
the main burner within four seconds from the time gas
reaches the main burner. In this test, the pilot flame is just
sufficient enough to hold in the Pilotstat® power unit or just
above the point of flame extinction (whichever occurs at a
higher pilot gas flow rate).
1. With the pilot and main burner operating, shut off the
main burner by either lowering the thermostat
temperature setting or turning the gas control knob to
the PILOT position.
NOTE:
If using a Honeywell W129A Millivoltmeter,
turn the pilot gas adjustment screw until the
thermocouple open circuit voltage is 2 mV,
omit steps 2, 3, and 4 and proceed with
step 5.
2. Turn the pilot gas adjustment screw clockwise until the
pilot begins to decrease in size. Then turn the pilot gas
adjustment screw clockwise 1/4 turn at a time (waiting
one minute between each turn to allow the
thermocouple to cool) until safety shutoff power unit just
drops out, causing safety shutdown.
3. Turn the pilot gas adjustment screw counterclockwise
slightly.
