036-21540-001-A-0503
Unitary Products Group
17
BLOWER SPEED ADJUSTMENT
The RPM of the supply air and condenser air blowers
will depend on the required CFM, and the static resis-
tance of both the supply/discharge and the return/
intake duct systems. With this information, the RPM for
the blowers can be determined from the blower perfor-
mance tables. Adjustment of blower speed is accom-
plished as follows:
1. Loosen belt tension by moving motor towards the
blower shaft via the adjustable mounting.
2. Loosen the setscrew in the adjustable motor pulley
flange. Remove key on pulleys 4-in. diameter and
larger.
3. Blower speed will increase when moveable flange
is adjusted towards the fixed flange (closed).
Blower speed will decrease when the moveable
flange is adjusted away from the fixed flange
(opened). Pulleys are adjustable only in half-turn
increments. Do not open pulley more than five full
turns for "4L" and "A" belts, or six full turns for "B"
belts.
4. Once the pulley has been opened/closed the
appropriate numbers of turns, replace the external
key and tighten the adjustment setscrew. Proper
torque is 110-130 in.-lbs.
5. Install drive belts and adjust motor mount to ten-
sion belt.
TABLE 4: MOTOR AND PULLEY DATA
EVAPORATOR
- STANDARD BLOWER MOTOR AND DRIVE DATA
Belts
HP
Frame
Eff.(%)
Pitch Dia.(in)
Browning #
Pitch Dia.(in)
Browning#
Rating / Size
Qty
3 TON
673-1010
1/3
56
68.0
2.0-3.0
1VP34 X 5/8
5.2
AK54H
4L370
1
4 TON
714-1071
1/2
56
75.0
2.0-3.0
1VP34 X 5/8
4.9
AK51H
4L370
1
5 TON
795-1193
3/4
56
75.0
2.0-3.0
1VP34 X 5/8
4.4
AK46H
4L360
1
8 TON
784-1045
1 1/2
145
84.0
3.0-4.0
1VP44 X 7/8
6.7
AK69H
4L380
1
10 TON
820-1094
2
145
84.0
3.0-4.0
1VP44 X 7/8
6.4
AK66H
4L370
1
12 TON
784-1045
2
145
84.0
3.0-4.0
1VP44 X 7/8
6.7
AK69H
4L370
1
15 TON
848-1064
5
184
87.5
4.7-5.9
1VP60 X 1-1/8
9.7
BK100H
B40
1
20 TON
848-1064
5
184
87.5
4.7-5.9
1VP60 X 1-1/8
9.7
BK100H
B50
1
25 TON
902-1082
7-1/2
213
88.5
5.0-6.0
1VP62 X 1-3/8
9.7
BK100H
BX51
1
EVAPORATOR
- OVERSIZE BLOWER MOTOR AND DRIVE DATA
Belts
HP
Frame
Eff.(%)
Pitch Dia.(in)
Browning #
Pitch Dia.(in)
Browning#
Rating / Size
Qty
3 TON
897-1346
1/2
56
68.0
2.0-3.0
1VP34 X 5/8
3.9
AK41H
4L350
1
4 TON
946-1419
3/4
56
75.0
2.0-3.0
1VP34 X 5/8
3.7
AK39H
4L350
1
5 TON
946-1419
1
56
75.0
2.0-3.0
1VP34 X 5/8
3.7
AK39H
4L350
1
8 TON
972-1296
2
145
84.0
3.0-4.0
1VP44 X 7/8
5.4
AK56H
4L360
1
10 TON
1068-1364
3
145
86.5
3.6-4.6
1VP50 X 1-1/8
5.9
AK61H
A35
1
12 TON
984-1258
3
145
86.5
3.6-4.6
1VP50 X 1-1/8
6.4
AK66H
A36
1
15 TON
848-1064
5
184
87.5
4.7-5.9
1VP60 X 1-1/8
8.2
BK85H
B36
1
20 TON
1046-1287
7-1/2
213
88.5
5.2-6.4
1VP65 X 1-3/8
8.8
BK90H
BX50
1
25 TON
1033-1296
10
213
88.5
4.7-5.9
1VP60 X 1-3/8
15.7
BK160H
BX60
1
CONDENSER
- STANDARD BLOWER MOTOR AND DRIVE DATA
Belts
HP
Frame
Eff.(%)
Pitch Dia.(in)
Browning #
Pitch Dia.(in)
Browning#
Rating / Size
Qty
3 TON
673-1010
1
143
82.5
2.0-3.0
1VP34 X 7/8
5.4
AK54H
4L400
1
4 TON
648-972
1
143
82.5
2.0-3.0
1VP34 X 7/8
5.4
AK56H
4L400
1
5 TON
771-1068
1 1/2
145
84.0
2.6-3.6
1VP40 X 7/8
5.9
AK61H
4L420
1
8 TON
761-1014
2
145
84.0
3.0-4.0
1VP44 X 7/8
6.9
AK71H
A65
1
10 TON
875-1118
3
182
86.5
3.6-4.6
1VP50 X 1-1/8
7.2
AK74H
A65
1
12 TON
685-875
3
184
86.5
3.6-4.6
1VP50 X 1-1/8
9.2
AK94H
A68
1
15 TON
794-974
5
184
87.5
4.4-5.4
1VP56 X 1-1/8
9.7
BK100H
B69
1
20 TON
717-882
7-1/2
213
87.5
5.2-6.4
1VP65 X 1-3/8
12.7
BK130H
B80
1
25 TON
717-882
7-1/2
213
87.5
5.2-6.4
1VP65 X 1-3/8
12.7
BK130H
B88
1
Adjustable
Motor Pulley
Fixed
Blower Pulley
Adjustable
Motor Pulley
Fixed
Blower Pulley
Drive Range
(RPM)
Motor
Adjustable
Motor Pulley
Model
Drive Range
(RPM)
Fixed
Blower Pulley
Model
Motor
Motor
Model
Drive Range
(RPM)
