Patent ID: 7559207

Claim:
A method for controlling refrigerant pressure in an HVAC system comprising the steps of: providing a compressor, a condenser and an evaporator connected in a closed refrigerant loop, the condenser having a header arrangement capable of distributing refrigerant to a plurality of refrigerant circuits within the condenser and capable of selectively isolating at least one of the circuits from refrigerant flow; providing at least one valve arrangement capable of controlling refrigerant flow into and out of at least one of the circuits that can be selectively isolated from refrigerant flow; sensing refrigerant pressure at a predetermined location in the refrigeration system; isolating at least one of the refrigerant circuits, in response to the sensed refrigerant pressure; selectively drawing refrigerant from the at least one refrigerant circuit isolated from refrigerant flow into the refrigerant loop to increase the refrigerant pressure in the refrigerant loop; and selectively drawing refrigerant into the at least one refrigerant circuit isolated from refrigerant flow from the refrigerant loop to decrease the refrigerant pressure in the refrigerant loop.