Bryant 575C, 575B, 541A dimensions IV. Complete Electrical Connections

IV. COMPLETE ELECTRICAL CONNECTIONS

A. Power Supply

Electrical characteristics of available power supply must agree with nameplate rating. Supply voltage must be within tolerances shown in Table 7. Phase imbalance must not exceed 2%. Operation of unit on improper supply voltage or with excessive phase imbalance constitutes abuse and is not covered by Bryant warranty.

Per local code requirements, provide an adequate fused disconnect switch within sight of unit and out of reach of children. Provision the switch for locking open (off) to prevent power from being turned on while unit is being serviced. The disconnect switch, fuses, and field wiring must comply with local requirements. Refer to Table 7 for unit electrical data.

B. Power Wiring

All power wiring must comply with applicable local require- ments. Run power wires from disconnect switch through unit power opening and connect to terminal block inside the unit control box. Unit must be grounded.

C. Unbalanced 3-Phase Supply Voltage

Never operate a motor where a phase imbalance in supply voltage is greater than 2%. Use the following formula to determine the percentage of voltage imbalance:

% Voltage Imbalance:

=100 x max voltage deviation from average voltage average voltage

Example: Supply voltage is 460-3-60.

AB = 452 v BC = 464 v AC = 455 v

452 + 464 + 455

Average Voltage =

3

= 1371 3

= 457

(AB) 457 – 452 = 5 v

(BC) 464 – 457 = 7 v

(AC) 457 – 455 = 2 v Maximum deviation is 7 v.

Determine percent of voltage imbalance. % Voltage Imbalance= 100 x 4577

= 1.53%

This amount of phase imbalance is satisfactory as it is below the maximum allowable 2%.

IMPORTANT: If the supply voltage phase imbalance is more than 2%, contact your local electric utility company immediately.

WARNING: Unit cabinet must have an uninter- rupted, unbroken electrical ground to minimize the possibility of personal injury if an electrical fault should occur. This ground may consist of electrical wire connected to unit ground lug in control compartment, or conduit approved for electrical ground when installed in accordance with NEC (National Electrical Code), ANSI/NFPA (American National Standards Institute/National Fire Protection Association), and local electrical codes. Failure to follow this warning could result in the installer being liable for personal injury of others.

IMPORTANT: Operation of unit on improper power supply voltage or with excessive phase imbalance constitutes abuse and is not covered by Bryant warranty.

D. General Wiring Notes (See Fig. 8-13)

1.A crankcase heater is wired in the control circuit so it is always operable as long as power supply disconnect is on, even if any safety device is open or unit stop/ start switch is off.

2.The power-circuit field supply disconnect should never be open except when unit is being serviced or is to be down for a prolonged period. When operation is resumed, crankcase heater should be energized for 24 hours before start-up. If system is to be shut down for a prolonged period, it is recommended that the suction and discharge valves be closed to prevent an excessive accumulation of refrigerant in the com- pressor oil.

3.Terminals for field power supply are suitable for cop- per, copper-clad aluminum, or aluminum conductors.

4.Bryant recommends an indoor airflow switch (field supplied) be installed and interlocked with the outdoor unit. This prevents the outdoor unit from operating if indoor airflow fails (broken fan belt, etc.). Operation of the compressor in vacuum can damage bearing surfaces. Install indoor airflow switch in a convenient location at the indoor supply air duct and wire per Fig. 14.

5.If the system is equipped with an accessory electric heater, refer to the 524A-H installation instructions and tables.

E.Control Circuit Wiring

Control voltage is 24 v. See unit label diagram for field supplied wiring details. Route control wires through opening in unit to connection in unit control box.

Control Transformer Wiring

On 208/230V units, check the transformer primary wiring connections. See Fig. 8 or refer to unit label diagram.

For 575B,C Unit — If unit will be operating at 208-3-60 power, remove black wire (BLK) from the transformer pri- mary connection labeled “230” and move it to the connection labeled “208”. See Fig. 8.

For 541A Unit — Transformers no. 1 and 2 are wired for a 230-v unit. If a 208/230-v unit is to be run with a 208-v power supply, the transformers must be rewired as follows:

1.Remove cap from red (208 v) wire.

2.Remove cap from orange (230 v) spliced wire.

3.Replace orange wire with red wire.

4.Recap both wires.

IMPORTANT: BE CERTAIN UNUSED WIRES ARE CAPPED. Failure to do so may result in damage to the transformer.

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