2. Turn gas ON and remove adjustment screw cover on
gas valve. Turn counterclockwise to decrease pressure
and clockwise to increase.
NOTE: Adjustment screw cover MUST be placed on gas
valve before reading manifold pressure and operating
furnace.
Fire and/or explosion hazard.
Do NOT adjust manifold pressure more than -+0.3 inches
water column to obtain rated input.
Failure to properly set input pressure can result in proper-
ty damage, personal injury and/or death.
3. Set pressure to value shown in FIGURE 11, ± 0.07kPa
(0.3 inches) water column. Pressure is also listed on
furnace rating plate. In NO case should final manifold
pressure vary more than ± 0.07kPa (0.3 inches) water
column.
CIRCULATING AIR BLOWER
Check the unit's operation as outlined in the following
instructions, tf any unusual sparking, odors or unusual
noises are encountered, shut off electric power
immediately. Recheck for wiring errors, or obstructions in or
near blower motors.
1. Set thermostat Heat-Cool selector to OFE
2. Set thermostat fan switch to AUTO.
3. Turn electric power ON. Nothing should start running.
4. Turn manual gas valve ON.
5. Turn gas control valve ON.
6. Set thermostat fan switch to ON.
7. Reset thermostat fan switch to AUTO.
HEATING START-UP PROCEDURE
1. Adjust thermostat setting above room temperature and
set thermostat selector to HEAT. The combustion air
blower should come ON.
2. The ignitor should begin to glow and pilot flame should
light. Refer to Lighting/Operating Instructions label lo-
cated on Burner Access Panel of unit.
NOTE: On a call for heat the ignitor and pilot valve will
remain energized until a flame is detected by the flame
sensor. It may take several minutes to purge the air out of
the gas lines at initial start-up of the unit.
3. Once the flame sensor detects that a flame is present,
the hot surface ignitor will de-energize and the main
burners will light from the pilot.
4.30 seconds after the burners light, the circulating blow-
er should begin to run.
Fire and/or explosion hazard.
Do NOT attempt to light the pilot or burner with a match or
flame of any kind.
Failure to follow this warning can result in property damage,
personal injury, and/or death.
Temperature Rise Check
NOTE: Air temperature rise is the temperature difference
between supply and return air. With a properly designed
distribution system, the proper amount of temperature rise
will normally be obtained when the unit is operating at rated
input with the recommended blower speed.
1. The temperature rise must be within the specifications
marked on the unit rating plate.
To check the temperature rise through the unit, place ther-
mometers in the supply and return air ducts as close to the
unit as possible.
Open ALL registers and duct dampers. Operate unit AT
LEAST 15 minutes before taking readings,
If the correct amount of temperature rise is not obtained
when operating on the recommended blower speed, it may
be necessary to change the blower speed. A faster blower
speed will decrease the temperature rise. A slower blower
speed will increase the temperature rise.
NOTE: The blower speed MUST be set to give the correct
air temperature rise through the furnace as marked on the
rating plate. See FIGURE 13 for more information.
2. After 15 minutes of operation check the limit control
function by blocking the
return air grille(s).
After several minutes the main burners and pilot should
go OFF. The circulating air blower should continue to
run.
Remove air restrictions. Pilot and main burners should
relight after a cool down period of a few minutes.
3. Adjust the thermostat setting below room temperature.
Pilot and main burners and combustion air blower
should go OFF.
The circulating air blower should continue to run for 60,
100, 14-0or 180 seconds. This time is adjustable. See
FIGURE 12 for more information.
4. Set thermostat Heat-Cool selector to OFF.
FANCONTROLCHECK
462 01 1003 01
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