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Temperature Rise Check
Check the temperature rise through the unit by placing thermometers in supply and return air registers as close to the unit
as possible. Thermometers must not be able to sample temperature directly from the unit 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 specified on the rating plate.
NOTE: Air temperature rise is the temperature difference between supply and return air.
With a properly designed system, the proper amount of temperature rise will normally be obtained when the unit is operated at
rated input with the recommended blower speed.
If the correct amount of temperature rise is not obtained, it may be necessary to change the blower speed. A higher blower speed
will lower 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 unit as marked on the rating plate.
External Static Pressure Check
The total external static pressure must be checked on this unit to determine if the airflow is proper.
Blower Speed Adjustments
Refer to the wiring diagram and airflow data in the appendix to
verify speed tap settings.
Depending upon the model, blower speeds are changed at the
indoor blower. The ignition control board has four blower speeds:
LOW HEAT, HI HEAT, LOW COOL and HIGH COOL.
NOTE:
FAN ONLY energizes at LOW HEAT speed.
The *PD14 models are equipped with EEM motors. EEM motors are
constant torque motors with very low power consumption. This
motor is energized by 24VAC. Adjust the CFM for the unit by
changing the 24VAC leads to the speed terminal block on the
motor.
NOTE: Heating airflow must be adjusted to provide the temperature
rise shown on rating plate. A higher speed tap may not provide
more airflow. Blower speeds are programmed to deliver adequate
airflow at rated external static pressure (ESP). Refer to airflow
table provided in the Appendix for details.
Limit Check
Check limit control operation after 15 minutes of operation by
blocking the return air grille(s).
1. After several minutes the main burners must go OFF. Blower will continue
to run.
2. Remove air restrictions and main burners will relight after a cool down
period of a few minutes.
Adjust the thermostat setting below room temperature.
1. Main burners must go OFF.
2. Circulating Air Blower will continue to run for 90, 120, 150 or 180 seconds,
depending on the setting.
NOTE: If necessary, adjust fan OFF delay settings to obtain satisfactory com-
fort level.
Unit Shutdown
1. Set the thermostat to lowest setting.
2. Turn off the electrical power supply to the unit.
3. Remove the heat exchanger door on the side of the unit by removing
screws.
4. Move the gas control valve switch to the OFF position. Do
not force.
5. Close manual gas shutoff valve external to the unit.
6. Replace the heat exchanger door on the unit.
7. If cooling and/or air circulation will be desired, turn ON
the electrical power.
T
O AVOID PERSONAL INJURY OR DEATH DUE TO ELECTRIC SHOCK, REMOVE
ELECTRICAL POWER FROM THE UNIT BEFORE CHANGING SPEED TAPS ON THE
BLOWER MOTOR.
GAS HEATING
Lead
Speed
Definition
Color
Tap
White
T1
Speed Heat
High
Brown
T2
Speed Heat
LO COOL
U6
HI COOL
U7
LO HEAT
U4
HI HEAT
U5
SPEEDUP
SW1
FAULT
BLOWER
STAGE
RECALL
OFF DELAY
DELAY
18
WARNING
COOLING
Lead
Speed
Color
Tap
Low
T3
Yellow
T4
T5
U3
K2
P1
F1
C W1 W2 G Y1 Y2
R
ECON
Control Board (Top)
Definition
Cool/HP
Optional Low
Speed
Cool/HP
Speed
High Static
K1
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