Bryant 575A Field Control Wiring, START-UP Preliminary Checks, II. Evacuate and Dehydrate

C. Field Control Wiring

Install an approved accessory thermostat assembly accord- ing to installation instructions included with the accessory. Locate thermostat assembly on a solid wall in the condi- tioned space to sense average temperature in accordance with thermostat installation instructions.

Route thermostat cable or equivalent single leads of colored wire from subbase terminals to low-voltage connections on unit (shown in Fig. 9) as described in following Steps 1 through 3:

1.Pass the control wires through the hole provided in the corner post. (See Fig. 10.)

2.Feed wire through the raceway built into the corner post to the 24-v barriers located on the left side of the con- trol box. The raceway provides the required clearance between the high- and low-voltage wiring.

3.Connect thermostat wires to screw terminals of low- voltage connection board.

NOTE: 39 VA is available for ®eld-installed accessories. Con- trol power requirement for heat pump outdoor unit is 36 VA (sealed). The factory-supplied control transformer is rated at 75 VA.

NOTE: For wire runs, use the following insulated wire:

LENGTH		INSULATION		SIZE
Ft	M	RATING (C)	AWG		sq mm
0-50	0-15.2	35	18		0.82
50-75	15.2-22.9	35	16		1.30
Over 75	Over 22.9	35	14		2.08

LEGEND

AWG Ð American Wire Gage

CORNER	RACEWAY	THERMOSTAT	POWER WIRING
POST		FIELD CONNECTION	CONNECTIONS

Fig. 10 Ð Field Control Wiring Raceway

START-UP

I.PRELIMINARY CHECKS

1.Check that all internal wiring connections are tight and that all barriers, covers, and panels are in place.

2.Field electrical power source must agree with unit name- plate rating.

3.Ensure all service valves are open. Ensure all compres- sor service valves are backseated.

4.Verify that compressor holddown bolts have been loos- ened and that ¯at/snubber washers can be rotated by ®nger pressure (snug, but not tight).

5.Verify compressor crankcase heater is securely in place. Crankcase heater must operate for at least 24 hours be- fore start-up.

6.Note that compressor oil level is visible in the sight glass.

7.Check for leaks in refrigerant system by using soap bubbles and/or electronic leak detector.

8.Check voltage imbalance as shown in Table 4, Note 2.

All wire larger than no. 18 AWG (American Wire Gage) can- not be directly connected to the thermostat and will require a junction box and splice at the thermostat.

9.Check that both outdoor and indoor units are properly mounted in accordance with installation instructions and applicable codes.

	LEGEND
C	Ð Cooling	LLSV	Ð Liquid Line Solenoid
H	Ð Heating		Valve
HR	Ð Heater Relay	SUPL Ð Supplemental
IFC Ð Indoor Fan Contactor		TB	Ð Terminal Block

Fig. 9 Ð Control Wiring Connections

II. EVACUATE AND DEHYDRATE

Evacuate and dehydrate entire refrigerant system using meth- ods described in GTAC II, Module 4, System Dehydration.

III. REFRIGERANT AND OIL CHARGE

Refer to GTAC II, Module 5, Charging Recovery, Recycling, and Reclamation.

NOTE: Use of a Totalclaim refrigeration recovery unit is highly recommended when recovering refrigerant.

Unit panels must be in place when unit is operating during charging procedure.

Unit is shipped with holding charge only. Weigh in 15 lb of R-22 to start unit.

A. Refrigerant Charging

Use Cooling Charging Chart (see Fig. 11). Vary refrigerant until the conditions of the chart are met. Note that charging chart is different from the type normally used. Chart is based on charging the units to the correct subcooling for the vari- ous operating conditions. Accurate pressure gage and tem- perature sensing device are required. Connect the pressure gage to the service port on the liquid line service valve. Mount the temperature sensing device on the liquid line, close to the liquid line service valve, and insulate it so that outdoor am- bient temperature does not affect the reading. Indoor air¯ow must be within the normal operating range of the unit.

Operate unit a minimum of 15 minutes. Ensure pressure and temperature readings have stabilized. Plot liquid pressure and temperature on chart and add or reduce charge to meet curve. Adjust charge to conform with charging chart, using liquid pressure and temperature to read chart.

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