Carrier 38AH044-134 User Manual
Page 46
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Table 19A — One 2-Stage Thermostat Capacity
Control for 38AH044-084 Dual-Circuit Units
Table 20 — One 2-Stage Thermostat Capacity
Control for 38AH094-134 Units
UNIT
38AH
QUANTITY OF LOADED
COMPRESSOR CYLINDERS
SYSTEM
CAPACITY
(%)
Circuit
A
Circuit
B
Total
4
4
8
100
044
2
4
4
0
6
4
75
50
2
0
2
25
4
6
10
100
2
6
8
79
054
2
4
6'
59
4
0
4
42
2
0
2
21
6
6
12
100
4
6
10
84
064
2
6
6
0
8*
6
68
48
4
0
4
32
2
0
2'
16
6
6
12
100
4
6
10
86
074
2
6
6
0
8*
6
72
43
4
0
4
29
2
0
2'
15
084
6
4
2
6
4
2
6
6
6
0
0
0
12
10
8'
6
4
2*
100
83
66
50
33
17
'Requires units with VAV (variabie air voiume) factory-suppiied
option
NOTE- Units have 2 independent refrigeration circuits. Circuit Ais 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
6
4
2
100
75
50
25
10
100
8
81
054
6
6
60
56
4
37
2'
19'
12
100
10
82
064
8
6
64
56
4
36
2t
18
12
100
10
81
074
8
6
62
57
4
38
2t
19
084
12
10
8
6
4
2t
100
83
66
50
33
17
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
10
12
22
100
8
12
20
91
8
10
18
82
10
6
16
73
104
6
6
6
4
12
10
55
45
0
6
6
27
4
0
4
18
0
4
4
18
2f
0
2
9t
12
12
24
100
10
12
22
92
10
10
20
83
8'
10
18
75*
6
10
16
67
124
6
8*
14
58*
6
6
12
50
4
6
10
42
6
0
6
25
4
0
4
17
2'
0
2
8*
12
12
24
100
10
12
22
92
10
10
20
83
8'
10
18
75*
6
10
16
67
134
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 accessory unioader on lead 06E-265 compressor (At).
tRequires VAV (variable air volume) factory-installed option or ac
cessory unloader
’Requires VAV (variable air volume) unit or accessory unloader(s) field
installed on circuit lead compressor. Lead compressor is identified in
Table 16, page 39
tRequires field-installed accessory unloader on circuit lead compres
sor Lead compressor is identified in Table 16, page 39
NOTES-
1 Temperatures calculated with the minimum number of fans oper
ating per circuit
2 See Table 16, page 39, 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 adjustment nut
clockwise to bottom stop. (See Fig 46.) In this position, load-up
set point is 85 psig (586 kPag). Turn adjustment counter
clockwise to desired control set point. Every full turn clock
wise decreases the load-up set point by 7.5 psig (52 kPag).
PRESSURE DIFFERENTIAL — Pressure differential (dif
ference between cylinder load and unload points) is adjust
able from 6 to 22 psig (41 to 152 kPag). To adjust, turn pres
sure differential adjustment screw counterclockwise to back
stop position. The differential pressure is now adjusted to 6
psig (41 kPag). Turn the adjustment screw clockwise to ad
just the differential pressure. Every full clockwise turn in
creases the differential by 1.5 psig (10 kPag).
46