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32. INDOOR BLOWER OPERATION
All models have multiple speed direct drive blower
motors. If supply and return ducts are connected to the
unit, the ducts must be of adequate size. Refer to the
appropriate blower tables. See Tables 10, 11, 12, 13,
14 and 15 for maximum static pressures acceptable.
Note the minimum CFM for cooling operation.
If voltage and duct design permit, (see blower tables)
single speed operation can be achieved as follows:
BLOWER MOTOR SPEED CHANGE
1. Disconnect power supply to unit.
2. Place desired blower motor speed lead wire to
"COOL" terminal of integrated furnace control
board.
3. Place desired blower motor speed lead wire to
"HEAT" terminal of integrated furnace control
board.
4. Place unused blower motor speed lead wire to
"UNUSED" terminal of integrated furnace control
board.
5. Energize the system in cooling and heating modes to
check for proper blower operation.
* NOTE: On 460 Volt motors, there are two motor isolation leads. The orange must connect with the black high
speed blower motor lead wire for medium and low speed blower operation. The purple wire must
connect with the blue medium speed blower motor lead wire for low speed blower operation. This is all
automatically accomplished with blower relays HSBR, MSBR and LSBR, and speed changes are all
made by changes at the integrated furnace control board.
FURNACE CONTROL BOARD AND BLOWER CONTROL
FIGURE 18
If it is desirable to have both HEAT/COOL blower
motor speed at the same speed, install a jumper wire
between "HEAT" and "COOL" terminals of the
integrated furnace control board, and place both unused
motor speed lead wires on the two "UNUSED" terminals
on the integrated furnace control board. (See Figure 18.)
230 VOLT MOTOR SPEED TAPS
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460 VOLT MOTOR SPEED TAPS
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TABLE 9
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2100-535
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