18
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.
Checking Temperature Rise
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 tem
-
perature 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.
Total External Static Testing
1. Using a digital manometer measure the static pressure
of the return duct at the inlet of the unit (Negative
Pressure).
2. Measure the static pressure of the supply duct
(Positive Measure).
3. Add the two readings together.
NOTE:
Both readings may be taken simultaneously and read
directly on the manometer if so desired.
4. Consult proper table for quantity of air. If the external
static pressure exceeds the minimum or maximum
allowable statics. Check for closed dampers, dirty
filters, undersized or poorly laid out ductwork.
Blower Speed Adjustments
WARNING
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.
Refer to the wiring diagram in the appendix to verify
speed tap settings.
All models are equipped with EEM motors. EEM
motors are constant torque motors with very low power
consumption. This motor is energized by 24V. Adjust the
CFM for the unit by changing the 24V low voltage leads
to the speed terminal block on the motor.
Heating-White Lead
Cooling-Yellow Lead
T1 - Low Speed
T4 - Low Speed
T2 - Medium Speed
T5 - High Speed
T3 - High Speed
Speed
Tap
Definition
Lead
Color
Speed
Tap
Definition
Lead
Color
T1
Low
Speed Heat White
T3
Low Speed
Cool
Purple
T2
High
Speed Heat Brown
T4
High Speed
Cool
Yellow
T5
High Speed
Cool Hi-Static
HEATING
COOLING
NOTE:
Heating airflow must be adjusted to provide the tempera
-
ture rise shown on rating plate.
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.
