Instruction manual

15
Check Airflow (Variable Speed Motor)
For proper cooling operation, the airflow through the indoor coil
should be between 350 and 450 CFM per ton of cooling capacity
(or 350 - 450 CFM per 12,000 Btu/h) based on the rating of the
outdoor condensing unit.
IMPORTANT: The cooling blower speed must be set to provide a
minimum of 350 CFM airflow per ton (12,000 Btu/h) of outdoor
cooling capacity.
To change blower speed: Refer to “Wiring Diagram—
Blower (Variable Speed Motor).”
1. Disconnect all power supplies.
2. Locate the control board in the blower control box.
3. Set the HEAT and COOL taps by moving the board jumpers
to the A, B, C, or D positions (see Control Board Taps and
Dehumidify Resistor) based on the information found in the
Blower Performance Chart—Variable Speed Motor.
NOTE: If using a humidistat, the dehumidify resistor located
on the bottom right of the control board must be removed to
enable it. See Control Board Taps and Dehumidify Resistor.
The HUM terminal on the board must be connected to the
Normally Closed contact of the humidistat so that the board
senses an open circuit on high humidity. If a humidistat is
used, the dehumidify LED (see D1 below) will light when the
humidistat opens and the motor runs at reduced airflow.
Blower Performance Chart
Air
Handler
Model
Blower
Speed
CFM @ ESP. - in. W.C.
0.1 0.2 0.3 0.4 0.5
18
Low* (Red) 655 647 628 578 480
Med (Blue) 794 786 747 672 555
High (Black) 1,074 1,000 913 809 672
24
Low (Red) 655 647 628 578 480
Med* (Blue) 794 786 747 672 555
High (Black) 1,074 1,000 913 809 672
30
Low (Red) 860 851 842 813 721
Med* (Blue) 1,020 1,006 1,003 963 886
High (Black) 1,199 1,195 1,182 1,121 1,033
36
Low* (Red) 1,135 1,120 1,112 1,079 995
Med (Blue) 1,354 1,345 1,317 1,260 1,090
High (Black) 1,494 1,469 1,417 1,336 1,250
42
Low (Red) 1,202 1,192 1,160 1,116 998
Med* (Blue) 1,404 1,413 1,386 1,303 1,192
High (Black) 1,540 1,530 1,507 1,386 1,254
48
Low (Red) 1,593 1,582 1,526 1,444 1,318
Med* (Blue) 1,759 1,709 1,636 1,538 1,395
High (Black) 1,886 1,820 1,742 1,606 1,446
60
Low (Red) 1,782 1,755 1,672 1,554 1,393
Med* (Blue) 2,066 1,960 1,860 1,714 1,476
High (Black) 2,109 2,067 1,949 1,770 1,586
All data given while air handler is operating with a wet DX coil
and no air filter installed.
Speeds marked with an asterisk (*) are the factory settings for
both heating and cooling.
Cooling speeds should not be reduced below factory settings.
Different speeds can be set for heating mode.
WARNING
Electrical Shock Hazard
Disconnect all power supplies before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.