Carrier A Ð One 2-StageThermostat Capacity, Control for 38AH044-084 Dual-CircuitUnits

Table 19A Ð One 2-Stage Thermostat Capacity

Control for 38AH044-084 Dual-Circuit Units

	QUANTITY OF LOADED			SYSTEM
UNIT	COMPRESSOR CYLINDERS
				CAPACITY
38AH	Circuit	Circuit	Total	(%)
	A	B
	4	4	8	100
044	2	4	6	75
	4	0	4	50
	2	0	2	25
	4	6	10	100
054	2	6	8	79
	2	4	6*	59
	4	0	4	42
	2	0	2	21
	6	6	12	100
	4	6	10	84
064	2	6	8*	68
	6	0	6	48
	4	0	4	32
	2	0	2*	16
	6	6	12	100
	4	6	10	86
074	2	6	8*	72
	6	0	6	43
	4	0	4	29
	2	0	2*	15
	6	6	12	100
	4	6	10	83
084	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 Ð One 2-Stage Thermostat Capacity Control for 38AH044-084 Optional Single-Circuit Units

UNIT	QUANTITY OF	SYSTEM
		CAPACITY
38AH	LOADED CYLINDERS
		(%)
	8	100
044	6	75
	4	50
	2	25
	10	100
	8	81
054	6	60
	6	56
	4	37
	2*	19*
	12	100
	10	82
064	8	64
	6	56
	4	36
	2²	18
	12	100
	10	81
074	8	62
	6	57
	4	38
	2²	19
	12	100
	10	83
084	8	66
	6	50
	4	33
	2²	17

*Requires accessory unloader on lead 06E-265 compressor (A1). ²Requires VAV (variable air volume) factory-installed option or ac-

cessory unloader.

Table 20 Ð One 2-Stage Thermostat Capacity

Control for 38AH094-134 Units

UNIT	QUANTITY OF LOADED			SYSTEM
	COMPRESSOR CYLINDERS			CAPACITY
38AH
	Ckt A	Ckt B	Total	(%)
	10	6	16	100
	10	4	14	85
	10	2	12	70*
094	10	0	10	55
	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	12	55
	6	4	10	45
	0	6	6	27
	4	0	4	18
	0	4	4	18
	2²	0	2	9²
	12	12	24	100
	10	12	22	92
	10	10	20	83
	8*	10	18	75*
124	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*
	12	12	24	100
	10	12	22	92
	10	10	20	83
	8*	10	18	75*
134	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 identi®ed in Table 16, page 40.

²Requires ®eld-installed accessory unloader on circuit lead compres- sor. Lead compressor is identi®ed 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 Ð 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 Ð 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).

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