Carrier 38AH044-084 Capacity Control, Pressure Switch Settings Psig kPag, Switch Cutout CUT-IN

Page 47

Winter Start Control Ð A 21¤2-minute low-pressure switch (LPS) bypass function in the timer prevents nuisance LPS trips during start-up in low-ambient conditions.

High-Pressure Switch Ð This switch has nonadjust- able settings. Figure 29 shows connection on a cylinder head. See Table 18 for pressure switch settings.

NOTE: High-pressure switch must be removed from cylin- der head before removing compressor from the unit.

TO CHECK Ð Slowly close the discharge shutoff valve un- til the compressor shuts down. This should be at approxi- mately 426 psig (2935 kPag). Slowly open the valve. When the pressure drops to approximately 320 psig (2205 kPag), the pressure switch resets. To reenergize the control circuit, manually switch the fan circuit breaker off and then on. The compressor starts again under Time Guard controls.

Low-Pressure Switch Ð The low-pressure switch (LPS) has ®xed nonadjustable settings. It is located at the pump end of the compressor above the bearing head. See Table 18 for pressure switch settings.

TO CHECK Ð Slowly close the suction cut-off valve and allow the compressor to shut down. This should occur at approximately 27 psig (186 kPag). Slowly open the valve. The compressor restarts under Time Guard control when the pressure builds to approximately 67 psig (462 kPag).

Table 18 Ð Pressure Switch Settings,

Psig (kPag)

SWITCH

CUTOUT

CUT-IN

High

426 ± 7

320 ±

20

(2935 ± 48)

(2205

±

138)

 

Low

27

± 4

67

±

7

(186

± 28)

(462

±

48)

 

Capacity Control

38AH044-084 DUAL-CIRCUIT UNITS Ð Capacity con- trol is achieved by a pressure-actuated cylinder bank un- loader on lead compressor A1. As the cooling load decreases and the suction pressure drops, the unloader actuates at the pre-set suction pressure and unloads the cylinder bank. (See Fig. 44 and Table 19A.) The unloading of the compressor cylinder bank has no effect on the operation of lag compres- sor B2, which is controlled by TC2.

38AH044-084 SINGLE-CIRCUIT UNITS AND MOD- ULES 124A, 124B, 134A, AND 134B Ð Capacity control is achieved by a pressure-actuated cylinder bank unloader on lead compressor A1. See Table 16. As the cooling load decreases and the suction pressure drops, the unloader actuates at the pre-set suction pressure and unloads the cyl- inder bank. (See Fig. 44 and Table 19B and 20.) Lag com- pressor A2 is controlled by ®xed setting capacity control pressure switches (CCPSs) as follows:

 

CUT-IN Ð

CUTOUT Ð

 

Psi (kPa)

Psi (kPa)

CCPS 1

83 (572)

63 (531)

CCPS 2

80 (551)

53 (365)

CCPS Ð Capacity Control Pressure Switch

If suction pressure continues to drop after lead compres- sor A1 unloads and lag compressor A2 is operating, A2 will stop operating when the suction pressure drops to the CCPS cutout point.

38AH094,104 Ð Capacity control is achieved by a pressure- actuated cylinder bank unloader on the lead compressor (A1, B1) on each of the 2 refrigeration circuits. As the cool- ing load decreases and the suction pressure drops, the un- loader actuates at the pre-set suction pressure and unloads the cylinder bank. (See Fig. 44 and Table 20.) The unloading of the compressor cylinder bank has no effect on the opera- tion of the circuit lag compressor (A2, B2 [except 38AH094, circuit B]) which is controlled by ®xed setting capacity con- trol pressure switches (CCPSs) as follows:

 

CUT-IN Ð

CUTOUT Ð

 

Psi (kPa)

Psi (kPa)

CCPS 1

83 (572)

63 (531)

CCPS 2

80 (551)

53 (365)

CCPS Ð Capacity Control Pressure Switch

Pressure Relief Ð High-side pressure relief is pro- vided by a fusible plug in the liquid line at the service valve. For low-side pressure relief, a fusible plug is inserted in the side of the accumulator (all units except 38AH044-084 dual- circuit, constant-volume units). See Fig. 45. The 38AH044- 084 dual-circuit, constant-volume units have a fusible plug in the suction tubing. A pressure relief valve installed on the compressor relieves at 450 psig (3102 kPag) (see Fig. 1-6).

Unloader Settings

Unload, psig (kPag)

56 (386)

Load, psig (kPag)

76 (524)

 

 

*Unloader location.

Fig. 44 Ð Unloader Location and Settings

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Contents Installation, Start-Up Service Instructions Module Rigging Center of Gravity Ð in. mmUnit Check Compressor Mounting Unit Total Operational Corner WeightWeight Dimensions Ð Units 38AH044,054,064 Dimensions Ð Units 38AH074,084 Chart 1, Field Power Supply Connections Dimensions Ð Unit 38AH094Dimensions Ð Unit 38AH104 Dimensions Ð Unit 38AH124 Dimensions Ð Unit 38AH134 Ð Units 38AH044-084 Physical Data Ð 50/60 Hz SI Ð Units 38AH044-084 Physical Data Ð 50/60 Hz EnglishÐ Units 38AH094-134 Physical Data Ð 50/60 Hz SI Ð Units 38AH094-134 Physical Data Ð 50/60 Hz EnglishControl BOX Sheet Metal Cover Panel Removed Ð Typical Module with Cover Panels Removed Unit Maximum Liquid Lift Make Refrigerant Piping ConnectionsLiquid Lift Dual Circuit Single Circuit 38AH 044 STR Ð StreetPipe D Diameter Unit Total Linear Length of Interconnecting Pipe Ð FT M Unit 15¤8 21¤8 124B,134A 074 Total Linear Length of Interconnecting Pipe Ð FT Unit38AH 6.1 124B, 134A 07415-20 20-50 50-75 TXV Ð Thermostatic Expansion Valve TYP Ð Typical Units 38AH124 and 134 with Installed Piping Kit Fully Assembled Piping and Trim Kit Unit 38AH134 Shown Kit RailsÐ Electrical Data Ð 50/60 Hz 38AH044-084 Dual-Circuit Units Make Electrical ConnectionsRLA Optional SINGLE-CIRCUIT Unit CompressorFLA CKT Model Electrical Data Ð 50/60 Hz Units 38AH094,104Unit Voltage Nameplate Supply COMPRESSOR² MCA DesignationControl Circuit Electrical Data Ð 50/60 Hz Electrical Data Ð 50/60 Hz Units 38AH124Unit 38AH Module Fan Motor Electrical DataUnit Condenser FAN 38AH Nameplate Qty Total No.* FLA Each No.* LRA EachLength Ð Insulated Wire Ð AWG Length Ð Insulated Wire Ð AWG Field Wiring, One 2-Stage Thermostat Ð Units 38AH094 Field Wiring, One 2-Stage Thermostat Ð Units 38AH124 GND Terminal Block for Field Wiring, Single ModuPanel Control, Unit 38AH094 Field Wiring, Single ModuPanel Control, Unit 38AH104 Field Wiring, Single ModuPanel Control, Units 38AH124 Control Power Install AccessoriesMain Power Connection and Control Circuit Wiring Main Power Connection Control Circuit06E Compressors, Typical Preliminary ChecksAdjust Refrigerant Charge Compressor, Lead Compressor Lag Index of Lead/Lag Circuits and Compressors044-084 094 104 124 134 38AH STD OPT Lead CircuitCharging Chart Ð Unit 38AH044 50/60 Hz Ð Dual Circuit Charging Chart Ð Unit 38AH064 50/60 Hz Ð Dual Circuit Page Page Charging Chart Ð Unit 38AH104 50/60 Hz Charging Chart Ð Unit 38AH094 50/60 HzFan Cycling Control Ð Psig kPag Control by Pressure ± 10 Switch Opens 160 Switch Closes 255Refrigerant Circuit CUT-IN Ð Cutout Ð Pressure Switch Settings Psig kPagSwitch Cutout CUT-IN Capacity ControlLoaded Cylinders Quantity of Loaded System Unit Compressor Cylinders38AH Circuit Total Unit Quantity System CapacityControl Timer Cycle Unit Control Box 06E-250 06E-265 06E-275 06E-299 Compressor Replacement Ð Perform the followingCompressor OIL Required Compressor Cycles on LOW-PRESSURE Switch Problem Solution Compressor does not RUNCompressor Stops on HIGH-PRESSURE Switch Troubleshooting Pre-Start-Up Preliminary InformationComp A1 Comp A2 Comp B1 Comp B2 Start-Up

38AH044-084 specifications

The Carrier 38AH044-084 is an innovative air conditioning unit designed to provide efficient cooling solutions for residential and light commercial applications. This model is a part of Carrier's Aqua Series and is well-regarded for its combination of performance, energy efficiency, and innovative features.

One of the standout characteristics of the Carrier 38AH044-084 is its high-efficiency rating, which often exceeds the minimum efficiency standards set by the Department of Energy. Its Seasonal Energy Efficiency Ratio (SEER) rating is commendable, indicating significant energy savings over traditional air conditioning units. This efficiency translates to lower utility bills and a reduced carbon footprint, making it an environmentally friendly option.

In terms of technology, the Carrier 38AH044-084 is equipped with a modern scroll compressor. This type of compressor is known for its durability and quiet operation, contributing to a more pleasant indoor environment. The unit also incorporates advanced refrigerant technology, often using R-410A refrigerant, which is recognized for its lower environmental impact compared to older refrigerants like R-22.

The design of the 38AH044-084 focuses on ease of installation and maintenance. The compact footprint makes it suitable for various installation scenarios, whether on rooftops or ground levels. Additionally, the unit is engineered for durability, featuring weather-resistant components that can withstand harsh environmental conditions.

Another notable feature is the advanced airflow system, which ensures even distribution of cooled air throughout the space. This technology minimizes hot spots and enhances overall comfort. Furthermore, the unit supports a range of thermostatic controls, allowing users to customize their cooling experience according to their specific needs.

The Carrier 38AH044-084 is also designed with noise reduction in mind. Its sound-dampening technology helps minimize operational noise, making it a suitable choice for residential areas where noise levels are a concern.

In summary, the Carrier 38AH044-084 offers an excellent combination of energy efficiency, advanced technology, and user-friendly features. Whether for a home or a light commercial space, this unit provides reliable cooling performance while maintaining a focus on environmental responsibility and occupant comfort. With its robust design and innovative capabilities, it's a solid choice for those seeking effective and efficient air conditioning solutions.
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