Bryant R-22 Major Components, StageControl Board, Field Connections, Two Stage Compressor

Quiet Shift

Quiet Shift is a field-selectable defrost mode which may eliminate occasional noise that could be heard at the start of the defrost cycle and restarting of the heating cycle. On a non-communicating system, this feature must be enabled by selecting the 3rd position of the 3-position dip switch. For communicating (Evolution) systems, it must be enabled at the User Interface. When activated, the following sequence of operation will occur. Reversing valve will energize and compressor will turn off for 30 seconds, then turn back on to complete defrost. At the end of the defrost cycle, the reversing valve de-energizes, compressor will turn off for another 30 seconds, and the fan will turn off for 40 seconds, before starting in the heating mode.

Liquid-Line Solenoid Accessory

In heat pump long-line applications, a liquid-line solenoid is required to control refrigerant migration in the heating mode. The solenoid should be installed near the outdoor unit with the arrow facing the outdoor unit. This is the direction of flow control. See application manual for long-line application details.

Accessory Liquid Solenoid with Evolution Communicating Control:

When using the Evolution Control, the liquid-line solenoid output is provided at the Y1 connection. Connect the solenoid as shown in the wiring label diagram. This is a 24vac output that is energized whenever the compressor is energized. It closes, in the compressor off mode, to prevent refrigerant migration into the unit through the liquid-line.

On Systems with Accessory Liquid Solenoid Using a Non-Communicating Thermostat:

The liquid solenoid is connect to the Y1 and C terminal connections. The liquid solenoid closes, in the compressor off mode, to prevent refrigerant migration into the unit through the liquid-line.

CHECK CHARGE

Charged in high or low stage

Factory charge amount and desired subcooling are shown on unit rating plate for high stage. Charging method is shown on information plate inside unit. To properly check or adjust charge, conditions must be favorable for subcooling charging. Favorable conditions exist when the outdoor temperature is between 70_F and 100_F (21.11_C and 37.78_C), and the indoor temperature is between 70_F and 80_F (21.11_C and 26.67_C). Follow the procedure below:

Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge by adding or removing 0.6 oz/ft (17.74 g/m) of 3/8 liquid line above or below 15ft (4.57 m) respectively.

For standard refrigerant line lengths (80 ft/24.38 m or less), allow system to operate in cooling mode at least 15 minutes. If conditions are favorable, check system charge by subcooling method. If any adjustment is necessary, adjust charge slowly and allow system to operate for 15 minutes to stabilize before declaring a properly charged system.

If the indoor temperature is above 80_F (26.67_C), and the outdoor temperature is in the favorable range, adjust system charge by weight based on line length and allow the indoor temperature to drop to 80_F (26.67_C) before attempting to check system charge by subcooling method as described above.

If the indoor temperature is below 70_F (21.11_C), or the outdoor temperature is not in the favorable range, adjust charge for line set length above or below 15ft (4.57 m) only. Charge level should then be appropriate for the system to achieve rated capacity. The charge level could then be checked at another time when the both indoor and outdoor temperatures are in a more favorable range.

NOTE: If line length is beyond 80 ft (24.38 m) or greater than 20 ft (6.10 m) vertical separation, See Long Line Guideline for special charging requirements.

Heating Check Chart Procedure

To check system operation during heating cycle, refer to the Heat Pump Charging Instructions label on outdoor unit. This chart indicates whether a correct relationship exists between system operating pressure and air temperature entering indoor and outdoor units. If pressure and temperature do not match on chart, system refrigerant charge may not be correct. Do not use chart to adjust refrigerant charge.

NOTE: In heating mode, check refrigerant charge only when pressures are stable. If in doubt, remove charge and weigh in correct refrigerant charge.

NOTE: When charging is necessary during heating season, charge must be weighed in accordance with unit rating plate, ±0.6 oz./ft (±17.74 g/m). of 3/8-in. liquid-line above or below 15 ft (4.57 m)., respectively.

EXAMPLE:

To calculate additional charge required for a 25-ft. line set:

25 ft. - 15 ft. = 10 ft. X 0.6 oz./ft. = 6 oz. of additional charge.

MAJOR COMPONENTS

2-Stage Control Board

The HP control board controls the following functions: S High and low stage compressor contactor operation S Outdoor fan motor operation

S Reversing valve operation S Defrost operation

S Low ambient cooling

S Crankcase heater operation

S Compressor external protection S Pressure switch monitoring

S Time Delays

Field Connections

On non-communicating (non-Evolution) system, the two-stage control receives 24vac low-voltage control system inputs through the R, C, Y1, Y2 and O connections located at the bottom of the control board (see Fig. 54.) On a non-communicating system, output W1 is connected at the bottom of the control board for auxiliary heat.

For a communicating system, use the ABCD Evolution connections.

Two Stage Compressor

The two stage compressor contains motor windings that provide 2-pole (3500 RPM) operation.

Compressor Internal Relief

The compressor is protected by an internal pressure relief (IPR) which relieves discharge gas into the compressor shell when differential between suction and discharge pressure exceeds 550-625 psi. The compressor is also protected by an internal overload attached to motor windings.

Compressor Control Contactor

The contactor has a 24volt coil. The electronic control board controls the operation of the contactor.

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