Bryant 538J-18-1 manual LOW Pressure Switch, VI. Service Valves, VII. Accurater Bypass Type Device

Table 3 — Electrical Data

		OPERATIONAL		COMPRESSOR			POWER SUPPLY
		VOLTAGE*
538J	V-PH-Hz
		Min	Max	RLA	LRA	Fan FLA	MCA	Max Fuse† or HACR-Type
								Ckt Bkr Amps
018				10.7	47.0	.70	14.1	25
024				13.2	59.0	.70	17.2	30
030	208/230-1-60	187	254	15.7	73.0	.70	20.3	35
036				15.7	93.0	.70	20.3	35
048				24.3	131.0	.45	31.8	50
060				28.6	170.0	.45	37.2	65

		LEGEND
FLA	—	Full Load Amps
HACR —		Heating, Air Conditioning, Refrigeration
LRA	—	Locked Rotor Amps
MCA	—	Minimum Circuit Amps per NEC Section 430-24
NEC	—	National Electrical Code (U.S.A. Standard)
RLA	—	Rated Load Amps (Compressor)

*Permissible limits of the voltage range at which unit will operate satisfactorily.

†Time-delay fuse.

NOTES:

1. Control circuit is 24 v on all units and requires an external power source.

2.All motors and compressors contain internal overload protection.

3.In compliance with NEC (U.S.A. Standard) requirements for multimotor and combination load equipment (refer to NEC Articles 430 and 440), the overcurrent protective device for the unit shall be fuse or HACR breaker.

4.Motor RLA values are established in accordance with UL (Underwriters’ Laboratories) Standard 465 (U.S.A. Standard).

V. LOW PRESSURE SWITCH

This switch, mounted on the suction line, has fixed non- adjustable settings. To check pressure switch, attach pres- sure gage to suction service valve gage port. Slowly close liquid shutoff valve and allow compressor to pump down. Do not allow compressor to pump down below 2 psig (14 kPa). Compressor should shut down when suction pressure drops to cutout pressure in Tables 1A and 1B, and should restart when pressure builds up to cut-in pressure shown after accessory CLO (compressor lockout) switch has been reset and accessory Time Guard® II device has completed its tim- ing cycle.

VI. SERVICE VALVES

The service valves in the outdoor unit come from the factory frontseated. This means the refrigerant charge is isolated from the line-set connection ports. To prevent damage to the valve, use a wet cloth or other acceptable heat sink material on the valve before brazing.

The service valves must be backseated (turned counterclock- wise until seated) before the service port caps can be removed and the hoses of the gage manifold connected. In this position, refrigerant has access from the through out- door and indoor unit. The service valve cannot be field repaired; only a complete valve or valve stem seal and service port caps are available for replacement.

VII. ACCURATER® (BYPASS TYPE) DEVICE

See Fig. 4 for bypass type AccuRater device components. The piston has a refrigerant metering hole through it. The retainer forms a stop for the piston in the refrigerant bypass mode and a sealing surface for liquid line flare connection. To check, clean or replace piston:

1.Shut off power to unit.

2.Pump down using Pumpdown Procedure section on page 7.

3.Remove liquid line flare connection from AccuRater device.

4.Pull retainer out of body, being careful not to scratch flare sealing surface. If retainer does not pull out easily, carefully use locking pliers to remove retainer.

5.Slide piston out by inserting a small soft wire, with small kinks, through metering hole. Ensure metering

hole, sealing surface around piston cones, and fluted portion of piston are not damaged.

6.Clean piston refrigerant metering hole.

7.Replace retainer O-ring before reassembling Accu- Rater device (O-ring part no. 99CC501052).

VIII. REFRIGERANT CHARGING

WARNING: To prevent personal injury, wear safety glasses and gloves when handling refrigerant. Do not overcharge system — this can cause compressor flooding.

NOTE: Do not vent or depressurize unit refrigerant to atmo- sphere. Remove and recover refrigerant following practice.

A. Superheat Method (Cooling, Non-TXV)

To check and adjust charge during cooling season, use Tables 4A-5B and the following procedure:

1.Operate unit a minimum of 15 minutes before check- ing charge.

2.Measure suction pressure by attaching a gage to suc- tion valve service port.

3.Measure suction line temperature by attaching a ser- vice thermometer to unit suction line near suction valve. Insulate thermometer for accurate readings.

4.Measure outdoor coil inlet-air dry bulb temperature with a second thermometer.

5.Measure indoor coil inlet-air wet bulb temperature with a sling psychrometer.

6.Refer to Tables 4A and 4B. Find air temperature enter- ing outdoor coil and wet-bulb temperature entering indoor coil. At this intersection, note the superheat temperature.

7.Refer to Tables 5A and 5B. Find superheat tempera- ture and suction pressure and note suction line temperature.

8.If unit has higher suction line temperature than charted temperature, add refrigerant until charted temperature is reached.

9.If unit has lower suction line temperature than charted temperature, remove and recover refrigerant until charted temperature is reached.

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