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)
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