036-21521-001-A-0103
8
Unitary Products Group
BLOWER PERFORMANCE
All units employ direct-drive blower motors with multi-
ple speed taps available. The motors have been
selected to deliver the nominal air volume against vary-
ing external static pressures when necessary. After
installation of the unit, it will be necessary to check the
air volume and change the motor speed connection
accordingly if the air volume is too high or too low. All
units are factory-wired with the medium speed winding
connected.
A simple method for approximating sufficient air vol-
ume is to measure the difference between the supply
and return air temperatures. In Heating mode, the air
temperature rise should be in the range of 20ºF to 30ºF.
In Cooling mode, the temperature drop should be
between 15ºF to 25ºF. If values are outside the appro-
priate range, increase or reduce the motor speed as
necessary.
TABLE 4: BLOWER PERFORMANCE (CFM)
EXTERNAL STATIC PRESSURE (in w.g.)
UNIT
SPEED
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
007
High
-
-
-
-
270
235
195
150
-
Med
-
-
260
240
210
175
-
-
-
Low
225
215
200
180
150
-
-
-
-
009
High
-
-
380
360
330
290
240
-
-
Med
350
340
325
300
270
235
-
-
-
Low
285
275
260
240
210
-
-
-
-
012
High
495
475
450
420
385
345
300
-
-
Med
470
455
430
400
365
325
-
-
-
Low
385
370
355
330
300
-
-
-
-
018
High
-
-
705
660
610
555
495
430
-
Med
-
700
660
615
565
510
450
-
-
Low
690
665
630
585
535
480
-
-
-
024
High
-
-
1005
950
890
820
740
650
-
Med
925
905
875
840
790
730
660
-
-
Low
-
-
780
765
725
660
590
-
-
030
High
-
-
1170
1120
1060
985
905
810
-
Med
1150
1125
1090
1045
990
925
850
765
-
Low
-
975
970
940
905
855
785
-
-
036
High
-
1390
1330
1270
1210
1140
1055
960
-
Med
1355
1320
1270
1215
1155
1085
1005
920
-
Low
1200
1190
1170
1130
1085
1020
950
-
-
048
High
-
-
1990
1915
1835
1750
1660
1550
1415
Med
1880
1860
1820
1770
1710
1640
1550
1450
1320
Low
-
1490
1485
1480
1460
1420
1360
1285
1160
060
High
2340
2280
2210
2140
2070
1990
1895
1790
1660
Med
2040
2030
2005
1970
1925
1860
1785
1700
1590
Low
-
-
1705
1700
1680
1660
1610
1540
-
Note:
Units are shipped pre-wired for Medium speed.
All airflow ratings are at lowest voltage rating of dual rating (i.e., 208 volt)
Airflow ratings include resistance of wet coil and clean air filters.