
SERVICING
32
1. Using a digital manometer measure the static
pressure of the return duct at the inlet of the unit,
(Negative Pressure).
Mode
.
Total External Static
2. Measure the static pressure of the supply duct,
(Positive Pressure).
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.
Adjusting Airflow
*PGM3 models are equipped with EEM motors. This
motor is energized by 24V. Adjust the CFM for the unit by
changing the 24V low voltage leads to the speed termi nal
block on the motor.
NOTE: Heating airflow must be adjusted to pro vide the
temperature rise shown on rating plate.
Heating-White Lead
Cooling-Yellow Lead
T1 - Low Speed
T4 - Low Speed
T2 - Medium Speed
T5 - High Speed
T3 - High Speed
The APGM5[24-48] models are equipped with ECM
circulating blower motors. the blower speed is adjusted
using the DIP switches on the ECM interface module
(located in the blower compartment (See Blower
Performance section for settings).
Speed Tap Switch 1 Switch 2
A
OFF
OFF
B
ON
OFF
C
OFF
ON
D
ON
ON
Electric Heat
DIP Switch Settings
Thermostat Switch 3
Switch 4
Single-Stage
N/A
ON
Two-Stage
N/A
OFF
DIP Switch Settings for
Single & Two-Stage Thermostat
Speed Tap Switch 5 Switch 6
A
OFF
OFF
B
ON
OFF
C
OFF
ON
D
ON
ON
Cooling/HP DIP Switch Settings
CFM
Switch 7
Switch 8
Plus 10%
ON
OFF
Normal
OFF
OFF
Minus 10%
OFF
ON
Speed Tap Adjustment
Through DIP Switches