Goodmans ASX, GSZ, ASZ, SSX, DSZ, DSX, GSX, SSZ manual Capacity Control

PRODUCT DESIGN

CAPACITY CONTROL

During the compression process, there are several pockets within the scroll that are compressing gas. Modulation is achieved by venting a portion of the gas in the first suction pocket back to the low side of the compressor thereby reducing the effective displacement of the compressor. See Figure A. Full capacity is achieved by blocking these vents, increasing the displacement to 100%. A solenoid in the compressor, controlled by an external 24-volt ac signal, moves the slider ring that covers and uncovers these vents. The vent covers are arranged in such a manner that the compressor operates somewhere around 67% capacity when the solenoid is not energized and 100% capacity when the solenoid is energized. The loading and unloading of the two step scroll is done “on the fly” without shutting off the motor between steps. See Figure B below. The unloaded mode default was chosen for two reasons:

FIGURE B

1.It is expected that the majority of run hours will be in the low capacity, unloaded mode.

2.It allows a simple two-stage thermostat to control capac- ity through the second stage in both cooling and possibly heating if desired.

UNLOADER SOLENOID

Anominal 24-volt direct current coil activates the internal unloader solenoid. The input control circuit voltage must be 18 to 28 volt ac. The coil power requirement is 20 VA. The external electrical connection is made with a molded plug assembly. This plug is connected to the Comfort Alert Module which contains a full wave rectifier to supply direct current to the unloader coil.

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