Bryant 556A, 552A, 550A Route Ground and Power Wires, Connect Ground and Power Wires, Xi. Start-Up

NOTE: Install branch circuit disconnect of adequate size per NEC to handle unit starting current. Locate disconnect within sight from and readily accessible from unit, per Section 440-14 of NEC.

A. ROUTE GROUND AND POWER WIRES

Remove access panel to gain access to unit wiring. Extend wires from disconnect through power wiring hole provided and into unit control box.

WARNING: The unit cabinet must have an uninter- rupted or unbroken ground to minimize personal injury if an electrical fault should occur. The ground may consist of electrical wire or metal conduit when installed in accordance with existing electrical codes. Failure to follow this warning can result in an electric shock, fire, or death.

B. CONNECT GROUND AND POWER WIRES

Connect ground wire to ground connection in control box for safety. Connect power wiring to contactor as shown in Fig. 9.

XI. START-UP

CAUTION: To prevent compressor damage or personal injury, observe the following:

• Do not overcharge system with refrigerant.

• Do not operate unit in a vacuum or at negative pressure.

•Do not disable low-pressure switch. In scroll compressor applications:

•Dome temperatures may be hot.

CAUTION: To prevent personal injury wear safety glasses, protective clothing, and gloves when handling refrigerant and observe the following:

• Back seating service valves are not equipped with Schrader valves. Fully back seat (counter clockwise) valve stem before removing gage port cap.

•Front seating service valves are equipped with Schrader valves.

DISCONNECT

PER N. E. C. AND/OR LOCAL CODES

FIELD POWER

WIRING

FIELD GROUND

WIRING

CONTACTOR

GROUND

LUG

A91056

CAUTION: Do not vent refrigerant to atmosphere. Re- cover during system repair or final unit disposal.

Follow these steps to properly start up the system:

1.	After system is evacuated, fully back seat (open) liquid and
	vapor service valves.
2.	Unit is shipped with valve stem(s) front seated (closed) and
	caps installed. Replace stem caps after system is opened to
	refrigerant flow (back seated). Replace caps finger-tight and
	tighten with wrench an additional 1/12 turn.
3.	Close electrical disconnects to energize system.
4.	Set room thermostat at desired temperature. Be sure set

Fig. 9—Line Power Connections

C. CONNECT CONTROL WIRING

Route 24-v control wires through control wiring grommet and connect leads to control wiring. (See Fig. 10.)

Use No. 18 AWG color-coded, insulated (35°C minimum) wire. If thermostat is located more than 100 ft from unit, as measured along the control voltage wires, use No. 16 AWG color-coded wire to avoid excessive voltage drop.

All wiring must be NEC Class 1 and must be separated from incoming power leads.

Use furnace transformer, fan coil transformer, or accessory trans- former for control power, 24-v/40-va minimum.

NOTE: Use of available 24-v accessories may exceed the mini- mum 40-va power requirement. Determine total transformer load- ing and increase the transformer capacity or split the load with an accessory transformer as required.

IX. COMPRESSOR CRANKCASE HEATER

When equipped with a crankcase heater, furnish power to heater a minimum of 24 hr before starting unit. To furnish power to heater only, set thermostat to OFF and close electrical disconnect to outdoor unit.

A crankcase heater is required if refrigerant tubing is longer than 50 ft. Refer to the Application Guideline and Service Manual—Air Conditioner with Puron® Refrigerant.

X. INSTALL ELECTRICAL ACCESSORIES

Refer to the individual instructions packaged with kits or acces- sories when installing.

point is below indoor ambient temperature.

5. Set room thermostat to COOL and fan control to ON or

AUTO mode, as desired. Operate unit for 15 minutes.

Check system refrigerant charge.

A. SEQUENCE OF OPERATION

Turn on power to indoor and outdoor units. Transformer is energized.

On a call for cooling, thermostat makes circuits R-Y and R-G. Circuit R-Y energizes contactor, starting outdoor fan motor and compressor circuit. R-G energizes indoor unit blower relay, starting indoor blower motor on high speed.

When thermostat is satisfied, its contacts open, de-energizing contactor and blower relay. Compressor and motors stop.

If indoor unit is equipped with a time-delay relay circuit, the indoor blower will run an additional 90 sec to increase system efficiency.

XII. CHECK CHARGE

A. UNIT CHARGE

Factory charge and charging method are shown on unit informa- tion plate. Puron® refrigerant cylinders contain a dip tube which allows liquid refrigerant to flow from cylinder in upright position. Charge Puron® units with cylinder in upright position and a commercial-type metering device in manifold hose. Charge refrigerant into suction line.

→NOTE: Charge must be adjusted in accordance with unit rating plate, ± 0.6 oz/ft of 3/8-in. liquid line above or below 15 ft, respectively.

→EXAMPLE:

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