Table 19A — One 2-Stage Thermostat Capacity
Control for 38AH044-084 Dual-Circuit Units
UNIT
38AH
QUANTITY OF LOADED
COMPRESSOR CYLINDERS
SYSTEM
CAPACITY
(%)
Circuit
A
Circuit
B
Total
044
4 4 8 100
24675
40450
20225
054
4 6 10 100
26879
2 4 6* 59
40442
20221
064
6 6 12 100
4 6 10 84
2 6 8* 68
60648
40432
2 0 2* 16
074
6 6 12 100
4 6 10 86
2 6 8* 72
60643
40429
2 0 2* 15
084
6 6 12 100
4 6 10 83
2 6 8* 66
60650
40433
2 0 2* 17
*Requires units with VAV (variable air volume) factory-supplied
option.
NOTE: Units have 2 independent refrigeration circuits. CircuitAis lead
circuit.
Table 19B — One 2-Stage Thermostat Capacity
Control for 38AH044-084 Optional Single-Circuit Units
UNIT
38AH
QUANTITY OF
LOADED CYLINDERS
SYSTEM
CAPACITY
(%)
044
8 100
675
450
225
054
10 100
881
660
656
437
2* 19*
064
12 100
10 82
864
656
436
2† 18
074
12 100
10 81
862
657
438
2† 19
084
12 100
10 83
866
650
433
2† 17
*Requires accessory unloader on lead 06E-265 compressor (A1).
†Requires VAV (variable air volume) factory-installed option or ac-
cessory unloader.
Table 20 — One 2-Stage Thermostat Capacity
Control for 38AH094-134 Units
UNIT
38AH
QUANTITY OF LOADED
COMPRESSOR CYLINDERS
SYSTEM
CAPACITY
(%)
Ckt A Ckt B Total
10 6 16 100
10 4 14 85
10 2 12 70*
10 0 10 55
094 80844
60633
40422
104
10 12 22 100
81220 91
81018 82
10 6 16 73
6 6 12 55
6 4 10 45
06627
40418
04418
2† 0 2 9†
124
12 12 24 100
10 12 22 92
10 10 20 83
8* 10 18 75*
61016 67
6 8* 14 58*
6 6 12 50
4 6 10 42
60625
40417
2* 0 2 8*
134
12 12 24 100
10 12 22 92
10 10 20 83
8* 10 18 75*
61016 67
6 8* 14 58*
6 6 12 50
4 6 10 42
60625
40417
2* 0 2 8*
*Requires VAV (variable air volume) unit or accessory unloader(s) field
installed on circuit lead compressor. Lead compressor is identified in
Table 16, page 40.
†Requires field-installed accessory unloader on circuit lead compres-
sor. Lead compressor is identified in Table 16, page 40.
NOTES:
1. Temperatures calculated with the minimum number of fans oper-
ating per circuit.
2. See Table 16, page 40, for information on lead and lag circuits.
CONTROL SET POINT — Control set point (cylinder load
point) is adjustable from 0 to 85 psig (0 to 586 kPag).
To adjust the set point, turn the control set point adjust-
ment nut clockwise to bottom stop. (See Fig. 46.) In this
position, load-up set point is 85 psig (586 kPag). Turn
adjustment counterclockwise to desired control set point.
Every full turn clockwise decreases the load-up set point by
7.5 psig (52 kPag).
PRESSURE DIFFERENTIAL — Pressure differential
(difference between cylinder load and unload points) is
adjustable from 6 to 22 psig (41 to 152 kPag). To adjust,
turn pressure differential adjustment screw counterclock-
wise to back stop position. The differential pressure is now
adjusted to 6 psig (41 kPag). Turn the adjustment screw clock-
wise to adjust the differential pressure. Every full clockwise
turn increases the differential by 1.5 psig (10 kPag).
48
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