Copeland Scroll Two Stage Compressor | Mechanical HVAC Engineer's

A Copeland Digital Scroll compressor utilizes a piston attached to the top scroll. At the top of the compressor sits a modulation chamber, separating the chamber and the discharge gas is a small bleed port. A solenoid valve is piped between the top of the compressor and the suction line. When the solenoid valve is energized (open), discharge gas bypasses into the suction line lifting up on the piston, separating the scrolls which unloads the compressor (stops pumping). When the solenoid valve de