Start Up Procedure - Williams 3508232 Owner's Manual

Installing Your Furnace
Start-Up Procedure
Start the furnace using the procedures in section OPERATING
YOUR FURNACE.
WARNING: Danger of bodily injury or death.
Liquefied petroleum L.P. Gas is heavier than air
and it will settle in any low area, including open
depressions and it will remain there unless the area
is ventilated.
Never attempt start-up of unit before thoroughly
ventilating area.
Check the furnace operation as outlined in the following
instructions. If any sparking, odors or unusual noises are
encountered, shut off electric power immediately. Recheck for
wiring errors or obstructions in or near fan motor.
WARNING: Natural gas heating value (Btu per
cubic foot) can vary significantly. Therefore, it is
the installer's responsibility to see that Btu/hr. input
to the furnace is adjusted properly. Failure to do so
could cause combustion
asphyxiation, fire or explosion resulting in damage,
bodily injury or death. Refer to the National Fuel
Gas Code (NFPA 54) to be sure the furnace is
burning fuel at the proper rate.
Under firing could cause
condensation or ignition problems. Over firing could cause sooting
flame impingement or overheating of the heat exchanger.
Before starting natural gas input check, obtain heating value of
gas (BTU per cubic foot) at standard conditions from your local
supplier. This factor is used in "Check the Gas Input" section and
procedure.
CHECK GAS INPUT AND PRESSURES
For furnaces located at elevations between sea level and 2,000
feet, the measured input must not be greater than the input shown
on the rating plate of the furnace. For elevations above 2,000 feet,
the measured input must not exceed the input on the rating plate
reduced by 4 percent for each 1,000 feet that the furnace is above
sea level.
Gas supply pressure and manifold pressure with the burners
operating must also be as specified on the rating plate.
Type of Gas
Natural
L.P.
Rated input will be obtained on a heating value of 2,500 Btu/hr. for
propane at 10 inches manifold pressure with factory-sized orifices.
If L.P. Gas having a different heating value is supplied, orifices
must be changed by a qualified service technician before the
furnace is operated.
chamber failure,
inadequate heat, excessive
Manifold Pressure, In. W.C.
4.0
10.0
CHECK THE MANIFOLD GAS PRESSURE
A tapped opening is provided in the gas valve to facilitate
measuring the manifold gas pressure. A "U Tube" manometer
having a scale range from 0 to 12-inches of water should be used
for this measurement. The manifold pressure must be measured
with the burner and pilot operating. Any major changes in flow
must be made by changing the size of the burner orifice.
Check with your local gas supplier for proper orifice sizing.
CHECK THE GAS INPUT (NATURAL GAS ONLY)
To measure the input, using the gas meter, proceed as follows:
1. Turn off gas supply to all other appliances except the furnace.
2. With the furnace operating, time the smallest dial on the meter
for one complete revolution. If this is a 2-cubic-foot dial, divide
the seconds by 2. If it is a 1-cubic-foot dial, use the time in
seconds as is. This gives the seconds per cubic foot of gas
being delivered to the furnace.
3. Assuming natural gas with a heating value of 1,000 Btu per
cubic foot and 34-seconds per cubic foot used as determined
by step (2), then:
Seconds per hour = 3,600
Input = 1,000 x 3,600 / 34 = 106,000 Btu/hr.
This measured input must not be greater than the input
indicated on the nameplate of the furnace.
4. Relight all other appliances turned off in Step 1 above. Be
sure all pilots are operating.
ADJUST PILOT BURNER (STANDING PILOT MODELS ONLY)
PiIot fIame should surround 3/8 inch to 1/2 inch of the
thermocouple tip. To adjust, remove pilot adjustment screw on gas
valve. Turn screw counterclockwise to increase flame, clockwise
to decrease. Replace cap.
CHECK THERMOSTAT
Check thermostat operation. When set above room temperature
shown on the thermostat, the main burner should light. Make
certain the thermostat turns off the furnace when the room
temperature reaches the selected setting and starts the furnace
when room temperature falls a few degrees.
FIGURE 26 Thermostat
INDICATOR
LOWEST
SETTING