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On GUD models, the flame may be inspected through the
observation window on the front cover of the burner box.
Check the burner flames for:
1. Good adjustment
2. Stable, soft and blue
3. Not curling, floating, or lifting off.
Figure 30
Burner Flame
CHECK TEMPERATURE RISE
Check the temperature rise through the unit by placing
thermometers in supply and return air registers as close to
the furnace as possible. Thermometers must not be able
to "see" the heat exchangers, or false readings could be
obtained.
1. All registers must be open; all duct dampers must be
in their final (fully or partially open) position, and the
unit operated for 15 minutes before taking readings.
2. The temperature rise must be within the range speci-
fied on the rating plate.
Note: Air temperature rise is the temperature difference
between supply and return air.
With a properly designed system, the proper temperature
rise will normally be obtained when the unit is operated at
rated input with the recommended blower speed.
If the correct temperature rise is not obtained, it may be
necessary to change the blower speed. A higher blower
speed will decrease the temperature rise. A slower blower
speed will increase the temperature rise.
Note: Blower speed must be set to give the correct air
temperature rise through the furnace as marked on the
rating plate.
CHANGING BLOWER SPEEDS
WARNING
To avoid electrical shock, injury or death,
when changing speed taps turn off power
to the furnace.
A multispeed motor is used in the furnace blower. It
provides easy speed selection for both heating and cooling
air flow. The Specification Sheet shows the CFM and ESP
relationship for proper selection of heating and cooling
speeds. All furnaces ship as high speed for cooling and the
speed listed on the wiring diagram for heating. These
speeds should be adjusted by the installer to match the
local conditions.
Refer to the WIRING DIAGRAM on the furnace to connect
the correct motor leads to the correct control terminals. If
heating speed will equal cooling speed, use the jumper
wire provided. All unused motor leads that are not con-
nected to "park" terminals on the control must be taped.
CHECK LIMIT AND FAN CONTROL
WARNING
To avoid premature failure of heat
exchanger or possible property damage,
injury or fire, do not change the limit control,
which is factory preset.
Check limit control operation after 15 minutes of operation
by blocking the return air grille(s).
1. After several minutes the main burners will go OFF.
Blower will continue to run.
2. Remove air restrictions. Main burners will relight after
a few minutes.
TO TURN FURNACE OFF
Adjust the thermostat setting below room temperature.
1. Main burners will go OFF.
2. Circulating Air Blower will continue to run for 60, 90,
120 or 180 seconds.
3. Set the thermostat to lowest setting.
4. Turn off the electrical power supply to the furnace.
5. Remove the louvered door on the front of the furnace
by turning the latch screws 1/4 turn each.
6. White Rodgers Model 36E36 or 36E37 or Honeywell
Model VR-8205 (Figures 25 and 26): Turn the gas
control knob clockwise
White Rodgers Model 36E22 or 36E23 (Figure 27):
Push the selector switch to OFF.
7. Close manual gas cutoff valve external to the furnace.
8. Replace the door on the furnace.
AIR CIRCULATION BLOWER FAN TIMING
All items in this section refer to the air circulation blower
fan, not to the induced draft blower. The timing sequence
for the induced draft blower is not adjustable.
When a call for cooling occurs, the circulation fan will come
on following a five second delay. It will remain on for 45
seconds after the call for cooling ends. This fan timing is
not adjustable.
During normal heating operation, the circulation fan will
come on 36 seconds after the gas valve opens. This timing
is not adjustable.
As shipped, the circulation fan will remain on for 90
seconds after the gas valve closes. If desired, this timing
may be adjusted. The adjustment pins or switches are
near the low voltage terminal strip (see Figures 31 and 32).
25
to the OFF position.
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