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High Stage Enhanced Dehumidification Cooling: Using the
total static pressure for selecting the high stage cooling speed,
look up Table 5 to find lower speed/airflows available at that
total static pressure. All airflows highlighted in Table 5 are
acceptable for the Dehum speed. The speed chosen must
provide airflow of between 320 to 400 CFM per ton of cooling.
To activate the high stage enhanced dehumidification cooling
mode, the shunt jumper must be moved from the "No DH" to
the "DH" selection. (See Figure 11, close up.) Connect the
chosen fan speed wire to "DHUM" connection on the IFB Board
(see Figure 11).
Continuous Fan (All Models): Continuous fan speed is the
same speed as Low Stage Cooling.
To activate the high stage enhanced dehumidification cooling
mode, the shunt jumper in Figure 11 must be moved from the
No DH to DH selection (See Figure 11, close up).
Using the Same Fan Speed for More than One Mode: Some
fan speeds are ideal for more than one mode of operation. It is
permissible to use a field--supplied jumper wire to connect one
speed tap wire to two or more speed connections on the
Interface Fan Board (IFB). Jumper wires must use 18 AWG
wire with at least 2/64" insulation.
COOLING SEQUENCE OF OPERATION
a. Continuous Fan
(1.) Thermostat closes circuit R to G energizing the
blower motor for continuous fan. The indoor fan
is energized on low speed.
b. Cooling Mode
(1.) Low Stage: Thermostat closes R to G, R to Y1.
The compressor and indoor fan are energized on
low speed. The outdoor fan is also energized
(2.) High Stage: Thermostat closes R to G, R to Y1,
R to Y2. The compressor and indoor fan are
energized on high speed. The outdoor fan is also
energized.
c. Electric Heating Mode
(1.) Thermostat closes circuit R to W2 or W3, and R
to G. There are no on or off delays.
51901190402
DH
LOW COM
HIGH
QC5
QC6
QC4
H S C I
2 4 V
M OTO R
TA P S
US
K2
K4
K3
674
674
674
Q1
R13
R10
C5
C9
C4
R15
C8
R7 R9
D11 D6 D4 Z2
R11
R8
D4
C7
674
D5
D3
Pb
Pb
e
1
R2 R5 R3 R6 C3
P2
QC8
1
674
R
W2
Y
C
Y
J2
6 7 4
P1
DH
DH
DH W3 W2 Y2 G Y1 C
H K 6 1 E A 0 2 3
Shunt in
dehumidification
DH
DH
position
Shunt in no
dehumidification
DH DH
position
208/230 VAC Models
Figure 11 - - Interface Fan Board (IFB)
C
QC9
QC3
K1
QC2
674
R12
D2
QC1
C1
R1 D1
C2
F1
C6
Z1
R4
R14
JW2
P4
1
674
W3 W3
W2 W2
C
1
R
A12571
13
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