York 160.87-OM1, Operation And Maintenance Manual

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Description of system and fundamentals of
operation
System operation description
The YORK Model YK-EP Chiller is commonly applied to large air conditioning systems, but may
be used on other applications. The chiller consists of an two open motors, each mounted to a
compressor (with integral speed increasing gears), condenser, evaporator and variable flow
control.
The chiller is controlled by a modern state of the art Microcomputer Control Center that monitors
its operation. The Control Center is programmed by the operator to suit job specifications.
Automatic timed start-ups and shutdowns are also programmable to suit nighttime, weekends,
and holidays. The operating status, temperatures, pressures, and other information pertinent to
operation of the chiller are automatically displayed and read on a graphic display. Other displays
can be observed by pressing the keys as labeled on the Control Center. The chiller with the
OptiView Control Center is applied with an Electro-Mechanical Starter, YORK Solid State Starter
(optional), or Variable Speed Drive (optional). The economizer compressor motor is controlled by a
solid-state starter exclusively.
When the compressor motor is driven by a YORK Solid State Starter, one of three different starters
could be applied. Chillers are equipped with either the Style B Liquid Cooled Solid State Starter
(LCSSS), the Medium Voltage Solid State Starter (MVSSS) or Remote Mounted Medium Voltage Solid
State Starter (MVSSS).
Figure 2: Model YK-EP chiller
11 YK-EP Style B Centrifugal Chiller