York YMAE - Four-Pipe Cooling Mode; Four-Pipe Heating Mode

Four-pipe cooling mode
Low-pressure liquid refrigerant enters the cooling BPHE through solenoid valve SV2 through the
main EEV, it is evaporated and superheated by the heat energy absorbed from the chilled water.
Low-pressure vapor flow enters the compressor through the accumulator, where pressure and the
superheat are increased.
High-pressure vapor is fed to the ambient coils through the four-way reversing valve, where heat
is removed. Then, the refrigerant flows from the condenser coil to the EVI BPHE to be further
subcooled. Simultaneously, a portion of the subcooled refrigerant flow passes through the EVI’s
EEV, the refrigerant flow is evaporated and superheated in the EVI’s BPHE, then flows to the
compressor as a cool gas. Also happening parallel to this, the main portion of the subcooled liquid
refrigerant flow passes through the main EEV, significantly reducing the pressure causing the
cooling effect to occur in the BPHE before returning to compressor through the accumulator
starting the refrigerant cycle over.
Four-pipe heating mode
Low-pressure liquid refrigerant enters the air source coil through the main EEV, then passes
through SV1 and is fully evaporated and superheated by the energy absorbed from the ambient air.
Low-pressure superheated refrigerant vapor passes through the four-way reversing valve and the
accumulator, then enters the compressor where pressure and superheat are increased.
High-pressure superheated refrigerant vapor enters the main BPHE where heat is rejected to the
water. Then the refrigerant flows from the main BPHE to the EVI BPHE to be further subcooled.
Simultaneously, a portion of the subcooled refrigerant flow passes through the EVI’s EEV, the
refrigerant flow is evaporated and superheated in the EVI’s BPHE, then flows to the compressor as
a cool gas. Also happening parallel to this, the main portion of the subcooled liquid refrigerant flow
passes through the main EEV, significantly reducing the pressure for the air source coils to absorb
heat from the ambient air before returning to compressor through the accumulator starting the
refrigerant cycle over.
23YMAE Air-Cooled Inverter Scroll Chiller and Heat Pump