Refrigerant Flow Control - York YK Manual

FORM 160.75-EG1 (519)
Equipment Overview (Cont'd)
J. Security access to prevent unauthorized change of setpoints, to allow local or remote
control of the chiller, and to allow manual operation of the pre-rotation vanes and oil
pump. Access is through ID and password recognition, which is defined by three differ-
ent levels of user competence: view, operator, and service.
K. Trending data with the ability to customize points of once every second to once every
hour. The panel will trend up to 6 different parameters from a list of over 140, without
the need of an external monitoring system.
L. The operating program stored in non-volatile memory (EPROM) to eliminate repro-
gramming the chiller due to AC power failure or battery discharge. Programmed
setpoints are retained in lithium battery-backed RTC memory for a minimum of 5 years
with power removed from the system.
M. A fused connection through a transformer in the compressor motor starter to provide
individual over-current protected power for all controls.
N. A numbered terminal strip for all required field interlock wiring.
O. An RS-232 port to output all system operating data, shutdown/cycling message, and a
record of the last 10 cycling or safety shutdowns to a field-supplied printer. Data logs
to a printer at a set programmable interval. This data can be preprogrammed to print
from 1 minute to 1 day.
P. The capability to interface with a building automation system via hard-wired connec-
tions to each feature to provide:
1. Remote chiller start and stop
2. Remote leaving chiller liquid temperature adjust
3. Remote current limit setpoint adjust
4. Remote ready to start contacts
5. Safety shutdown contacts
6. Cycling shutdown contacts
7. Run contacts

REFRIGERANT FLOW CONTROL

Refrigerant flow to the evaporator is controlled by the YORK
system. Liquid refrigerant level is continuously monitored to provide optimum subcooler,
condenser and evaporator performance. The variable orifice electronically adjusts to all
Real-World operating conditions, providing the most efficient and reliable operation of
refrigerant flow control.
16
variable orifice control
®
JOHNSON CONTROLS