Carrier 38AH044-084 - Manual (Page 48)

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
2 4 6 75
4 0 4 50
2 0 2 25
054
4 6 10 100
2 6 8 79
2 4 6* 59
4 0 4 42
2 0 2 21
064
6 6 12 100
4 6 10 84
2 6 8* 68
6 0 6 48
4 0 4 32
2 0 2* 16
074
6 6 12 100
4 6 10 86
2 6 8* 72
6 0 6 43
4 0 4 29
2 0 2* 15
084
6 6 12 100
4 6 10 83
2 6 8* 66
6 0 6 50
4 0 4 33
2 0 2* 17
*Requires units with VAV (variable air volume) factory-supplied
option.
NOTE: Units have 2 independent refrigeration circuits. Circuit A is 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
6 75
4 50
2 25
054
10 100
8 81
6 60
6 56
4 37
2* 19*
064
12 100
10 82
8 64
6 56
4 36
2† 18
074
12 100
10 81
8 62
6 57
4 38
2† 19
084
12 100
10 83
8 66
6 50
4 33
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 8 0 8 44
6 0 6 33
4 0 4 22
104
10 12 22 100
8 12 20 91
8 10 18 82
10 6 16 73
6 6 12 55
6 4 10 45
0 6 6 27
4 0 4 18
0 4 4 18
2† 0 2 9†
124
12 12 24 100
10 12 22 92
10 10 20 83
8* 10 18 75*
6 10 16 67
6 8* 14 58*
6 6 12 50
4 6 10 42
6 0 6 25
4 0 4 17
2* 0 2 8*
134
12 12 24 100
10 12 22 92
10 10 20 83
8* 10 18 75*
6 10 16 67
6 8* 14 58*
6 6 12 50
4 6 10 42
6 0 6 25
4 0 4 17
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