York YK M3 M3 G4 operation manual Section, SYSTEM OPERATION DESCRIPTION See Fig

SECTION 1

DESCRIPTION OF SYSTEM AND FUNDAMENTALS OF OPERATION

	COMPRESSOR
CONTROL
CENTER	MOTOR

PRE-ROTATION

DISCHARGE LINEVANE

ACTUATOR

27385A

COOLER

	27382A
OIL RESERVOIR/	CONDENSER
PUMP

FIG. 1 – MODEL YK MILLENNIUM CHILLER

SYSTEM OPERATION DESCRIPTION (See Fig. 2)

The YORK Model YK Millennium Chiller is commonly applied to large air conditioning systems, but may be used on other applications. The chiller consists of an open motor mounted to a compressor (with integral speed increasing gears) condenser, cooler and flow control chamber.

The chiller is controlled by a modern state of the art MicroComputer Control Center which monitors its op- eration. The Control Center is programmed by the op- erator to suit job specifications. Automatic timed start- ups and shutdowns are also programmed to suit nighttime, weekends, and holidays. The operating sta- tus, temperatures, pressures, and other information per- tinent to operation of the chiller are automatically dis- played and read on a 40 character alphanumeric message display. Other displays can be observed by pressing the keys as labeled on the Control Center. The chiller with the MicroComputer Control Center is applied with an electro-mechanical starter, YORK Solid State Starter (optional), or Variable Speed Drive (op- tional).

In operation, a liquid (water or brine to be chilled) flows through the cooler, where boiling refrigerant absorbs heat from the water. The chilled liquid is then piped to fan coil units or other air conditioning terminal units, where it flows through finned coils, absorbing heat from the air. The warmed liquid is then returned to the chiller to complete the chilled liquid circuit.

The refrigerant vapor, which is produced by the boiling action in the cooler, flows to the compressor where the rotating impeller increases its pressure and tempera- ture and discharges it into the condenser. Water flowing through the condenser tubes absorbs heat from the re- frigerant vapor, causing it to condense. The condenser water is supplied to the chiller from an external source, usually a cooling tower.The condensed refrigerant drains from the condenser into the flow control chamber, where the flow restrictor meters the flow of liquid refrigerant to the cooler to complete the refrigerant circuit.

The major components of a chiller are selected to handle the refrigerant which would be evaporated at full load

4 YORK INTERNATIONAL