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The evaporator fan motor is factory set to provide 5 different fan
speeds to choose from for the various operation modes (see Table
4). All models are factory- -shipped for nominal high stage and low
stage cooling airflow operation at minimum external static
pressure. See Table 2.
Table 4 – 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:
Low Stage Cooling/Heat Pump (All Models): Using Tables 6 , 7,
and 8, 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, look up Table 5 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 IFB Board (see Fig. 11).
High Stage Cooling/Heat Pump (All Models):Using Table 6 , 7,
and 8, 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, look up Table 5 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 IFB Board (See Fig. 11).
High Stage Enhanced Dehumidification Cooling (208/230 VAC
Models): 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 Fig. 11, close up.) For 208/230 VAC
models, connect the chosen fan speed wire to "DHUM" connection
on the IFB Board (see Fig. 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 Fig. 11 must be moved from the No DH
to DH selection (See Fig. 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.
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,
and R to O. 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, and R to O. The compressor and indoor fan
are energized on high speed. The outdoor fan is
also energized.
51801210403
c. Electric Heating Mode
d. Heat Pump Heating
e. Heat Pump Heating with Auxiliary Heat
f. Defrost Mode
Step 4 — Defrost Control
Quiet Shift
Quiet Shift is a field- -selectable defrost mode, which will eliminate
occasional noise that could be heard at the start of defrost cycle and
restarting of heating cycle. It is selected by placing DIP switch 3
(on defrost board) in ON position.
When Quiet Shift switch is placed in ON position, and a defrost is
initiated, the following sequence of operation will occur. Reversing
valve will energize, outdoor fan will turn off, compressor will turn
off for 30 sec and then turn back on to complete defrost. At the
start of heating after conclusion of defrost reversing valve will
de- -energize, compressor will turn off for another 30 sec, and the
outdoor fan will stay off for 40 sec, before starting in the Heating
mode.
Defrost
The defrost control is a time/temperature control which includes a
field- -selectable time period (DIP switch 1 and 2 on the board)
between defrost cycles of 30, 60, 90, or 120 minutes (factory set at
60 minutes). To initiate a forced defrost, two options are available
depending on the status of the defrost thermostat.
Specifications are subject to change without notice.
(1.) Thermostat closes circuit R to W2 or W3, and R to
G. There are no on or off delays.
(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.
(1.) Thermostat closes circuits R to G, R to Y and R to
W/W1 or W2. The compressor, indoor and outdoor
fans are energized, as well as the electric heat
relays.
The defrost mode is automatically energized by the
defrost board during heating mode. The defrost board
energizes "O" (reversing valve) and "W2" (electric
heat). It also de- -energizes the outdoor fan. When defrost
is complete, unit will return to heating mode. If room
thermostat is satisfied during defrost, unit will shut
down and restart in defrost on next call for heat.
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