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factory- -shipped with 3 speed wires connected and 2 speed wires
available. The fan speed wires are color- -coded as follows:
Table 11 – Color Coding for Indoor Fan Motor Leads
Black = High Speed
Orange = Med --- High Speed
Red = Med Speed
Pink = Med --- Low Speed
Blue = Low Speed
Selection of Proper Fan Speeds for Operation
Modes:
NOTE: All models are factory- -shipped for nominal high stage
and low stage cooling airflow operation at minimum external static
pressure. Many models are factory- -shipped for nominal high stage
and/or low stage gas heating airflow at minimum external static
pressure. Tables 14 (208/230 VAC models) and 15 (460 VAC
models) provide airflow data for higher external static pressures.
Low Stage Gas Heating (208/230 VAC models): Table 13 and 14
show the suitability of each speed for a given external static
pressure for low stage gas heating. Any speed/static combination
that is outside the rise range is marked "NA" and must not be used.
For single phase units only, "High" blower speed is for high static,
high stage cooling only and must not be used for low stage gas
heating speed. The unit must operate within the low stage gas heat
rise range printed on the rating plate. Connect the chosen fan speed
wire to "LO HEAT" connection on the IGC Board (see Fig. 20).
High Stage Gas Heating (208/230 VAC models): Table 13 and
14 show the suitability of each speed for a given external static
pressure for high stage gas heating. Any speed/static combination
that is outside the rise range is marked "NA" and must not be used.
For single phase units only, "High" blower speed is for high static,
high stage cooling only and must not be used for high stage gas
heating speed. The unit must operate within the high stage gas heat
rise range printed on the rating plate. Connect the chosen fan speed
wire to "HI HEAT" connection on the IGC Board (see Fig. 20).
Gas Heating (460 VAC models): Table 15 shows the suitability of
each speed for a given external static pressure for gas heating
operation. Any speed/static combination that is outside the rise
range is marked "NA" and must not be used. The unit must operate
within the gas heat rise range printed on the rating plate. Connect
the chosen fan speed wire to "GAS HEAT" connection on the
Interface Fan Board (IFB, See Fig. 21).
Low Stage Cooling (All models): Using Tables 16, 17, and 18,
and the nominal airflow for low stage cooling (Table 1) find the
external static pressure drops for wet coil, economizer, and filter,
and add them to dry coil measured on the system. Using this total
static pressure, use Table 13 or 14 (208/230 VAC models) and
Table 15 (460 VAC models) to find the airflows available at the
total static pressure. For 208/230 VAC models, connect the chosen
fan speed wire to "LO COOL" connection on the IGC Board (see
Fig. 20). For 460 Vac models, connect the chosen fan speed wire to
"LOW" connection on the IFB (see Fig. 21).
High Stage Cooling (All models)Using Tables 16, 17, and 18,
find the external static pressure drops for wet coil, economizer, and
filter, and add them to dry coil measured on the system. Using this
total static pressure, use Table 13 or 14 (208/230 VAC models) and
Table 15 (460 VAC models) to find the airflows available at the
total static pressure. The speed chosen must provide airflow of
between 350 to 450 CFM per ton of cooling. For 208/230 VAC
models, connect the chosen fan speed wire to "HI COOL"
connection on the IGC Board (See Fig. 20). For 460 VAC models,
connect the chosen fan speed wire to "HIGH" connection on the
IFB (see Fig. 21).
High Stage Enhanced Dehumidification Cooling (208/230 VAC
Models): Using the total static pressure for selecting the high stage
cooling speed, use Table 13 or 14 to find lower speed/airflows
available at that total static pressure. All airflows highlighted in
Table 13 and 14 are acceptable for Dehum speed. The speed
chosen must provide airflow of between 320 to 400 CFM per ton
of cooling. For 208/230 VAC models, connect the chosen fan
speed wire to "DHUM" connection on the IGC Board (see Fig.
20).
To activate the high stage enhanced dehumidification cooling
mode, the shunt jumper in Fig. 20 must be moved from the No DH
to DH selection (See Fig. 20, close up).
Continuous Fan (All models): Continuous fan speed is the same
speed as Low Stage Cooling.
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 ener-
gized on high speed. The outdoor fan is also ener-
gized.
L2
L2 HIGH LOW
P2
T1
D 7
Q 3
C9
D 2 6
T 2
R 5 4
R 5 5
D 6
R 5 7
R 6 8
C 7
R 5 6
C 8
JW4
R 1 3
Q 1
Q 2
R 6 0
K 1 1 D 2 4
R 5 9
R 5 8
U 2
R 6 1
C 6
R 5 3
R 1 4
K 1 2
R 1 5
D 2 5
R 7 2
R 7 3
Z1
C 5
K 9
D 2 2
R 4 4
R 2
K 1 0
U 3
R 2 2
D 2 3
R 2 2
R 5 1
D 2 1
R 4 7
R 4 8
R 7 0
R 5
JW5
R 2 5
R 5 2
K 8
R 6
R 1 9
A N 1
C 2
C 3
F 1
D 5
JW9
C 1
M O V 1
R 4
R 1
R 3 4
R 4 6
R 4 9
D 3
J 1
D 1
1 8 0
D 2
1 5 0
D 4
1 2 0
9 0
BLOWER
OFF DELAY
dehumidification
Fig. 20 - - Interface Fan Board (IFB) 208/230 VAC Models
31
L1
CCH
K 5
K 4
K 3
C 1 1
D 1 4
D 1 2
JW6
P 3
D 1 3
Q 7
Q 6
D 1 9
D 2 8 D 2 0
R 6 7
D 1 8
R 6 6
D 1 7
R 6 9
D 1 6
K 7
D 1 5
D 1 0
R 6 5
K 6
Q 4
Q 5
C 1 0
D 2 7
K 2
R 6 3
R 6 2
D 9
D 8
R 6 4
JW3
C 4
R 4 3
R 4 5
R 3 2
R 3 3
R 2 9
K 1
R 3 0
R 1 7
R 1 8
R 3 8
R 3 9
R 4 1
R 4 2
R 3 5
R 3 6
R 2 0
R 2 1
R 2 6
R 2 7
R 2 4
P1
R 1 2
R 4 0
R 1 1
R 3 7
R 3
R 1 6
R 7
R 2 8
R 3 1
R 9
R 1 0
JW8
JW10
J 2
JW7
P 4
D H
D H
Y2 Y1 G W1W2 C R DH
DH
DH
DH
DH
Shunt in
Shunt in no
dehumidification
position
position
A13017
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