16.Explain the basic operations of a
combination ORI and ORD low ambient head pressure control valve.
Answer : ORD valve sense a factory preset pressure difference of 20 psi between the
receiver and compressor discharge , It will start to open and bypass hot compressor discharge gas to the receivers inlet The ORI valve stows refrigerant in the condenser to maintain the correct head pressure. Both the ORI and the ORD will work in conjunction of one another to maintain proper receiver pressure, regardless of outside temperature.