FORM 160.52-O1
33
YORK INTERNATIONAL
However, the current draw (amperes) by the compres-
sor motor cannot exceed the setting of the
% CURRENT
LIMIT
at any time during the unit operation, since the
MicroComputer Control Center 40 to 100% three-phase
peak current limit software function, plus the 3-phase
100% solid state overload current limiter (CM-2), on
Electro-Mechanical Starter applications, or the Solid
State Starter current Limit function will override the tem-
perature control function and prevent the Prerotation
Vanes from opening beyond the
% CURRENT LIMIT
setting.
If the load continues to decrease, after the Prerotation
Vanes are entirely closed, the chiller will be shut down
by the Low Water Temperature control (LWT) function
which is displayed on the Control Center as:
MON 10:30 AM LOW WATER TEMPERATURE AUTOSTART
This occurs when the leaving water temperature falls to
4°F (2.2°C) below setpoint or 36°F (2.2°C), whichever
is higher. The LWT is part of the Micro Board.
NOTE: If the temperature setpoint has been repro-
grammed within the last 10 minutes, the LWT
cutout is 36°F (2.2°C) for 10 minutes.
Condenser Water Temperature Control
The YORK Millennium chiller is designed to use less
power by taking advantage of lower than design tem-
peratures that are naturally produced by cooling tow-
ers throughout the operating year. Exact control of con-
denser water such as a cooling tower bypass, is not
necessary for most installations. The chiller requires only
that the minimum condenser water temperature be no
SYSTEM STARTING & SHUTDOWN SEQUENCE
OPERATOR INITIATED
FIG. 15
CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE
NOTES: 1. REF. MICROBOARD PROGRAM JUMPER JP6
2. REF. MICROBOARD PROGRAM JUMPER JP4
(NOTE 2)
LD00952
