132
YORK INTERNATIONAL
simply called the “Range” and is best described as the
maximum acce and - deviation from Setpoint.
The minimum acceptable temperature is the Lower
Range and is calculated by subtracting the “-” Range
from the Setpoint. The Lower Range is the lowest ac-
ceptable leaving temperature. The highest acceptable
temperature is referred to as the Upper Range and is
calculated by adding the “+” Range to the Setpoint. The
Upper Range is the highest acceptable leaving tempera-
ture. For example, if the desired Setpoint temperature
is 7°C (44.0°F) and the allowable deviation (+ / - Range)
from this temperature is +/- 1°C (2.0°F), then the micro
will attempt to control leaving chilled liquid tempera-
tures to 6°C (42.0°F) to 8°C (46.0°F). This can be
viewed pictorially as follows:
To assure that the chilled liquid leaving temperature
stays within the Control Range, the micro will attempt
to control the leaving temperature to the actual Setpoint
temperature. This is accomplished by analyzing the tem-
6. SETPOINTS KEYS & CHILLED LIQUID CONTROL
6.1
GENERAL
The microprocessor monitors leaving chilled liquid tem-
perature and adjusts the chiller cooling capacity to main-
tain this temperature within a programmed range. The
capacity is controlled by switching compressors on or
off, and by varying a load/unload current to each com-
pressor slide valve to adjust the capacity of the com-
pressors. The microprocessor controls chilled liquid
temperature through a combination of Fuzzy Logic con-
trol and internal timers. Fuzzy Logic enables the micro
to analyze the deviation from setpoint and the rate of
change and determine the amount of loading and un-
loading necessary to control to the desired chilled liq-
uid setpoint temperature. The micro also attempts to
maximize efficiency by spreading the cooling load be-
tween compressors, minimize compressor cycling, and
optimally utilize evaporator tube surface (maximize
efficiency). This method of control is suitable for both
water and brine cooling. Control setpoints can be pro-
grammed into the chiller to establish the desired range
of leaving chilled liquid operating temperatures. A de-
scription of the operation and programming follows.
6.2
CHILLED LIQUID TEMPERATURE
CONTROL
The Setpoints keys are used to program the required
chilled water liquid temperature for the application. This
is accomplished by programming the “Setpoint” and
the acceptable deviation (+ or - Range) This deviation is
29023A
7°C
(44.0°F)
SETPOINT
Temp.
(User
acceptable
leaving
chilled liquid
operating
range)
CONTROL
RANGE
8°C
(46.0°F)
6ºC
(42.0ºF)
SETPOINTS
KEYS
Micro Panel Contents
Summary of Contents for eco2 YCAS0425EB
Page 26: ...26 YORK INTERNATIONAL This page intentionally left blank Product Description ...
Page 49: ...49 YORK INTERNATIONAL FORM 201 18 NM8 This page intentionally left blank 7 ...
Page 60: ...60 YORK INTERNATIONAL FIG 20 CONTINUED ELEMENTARY DIAGRAM Technical Data ...
Page 65: ...65 YORK INTERNATIONAL FORM 201 18 NM8 WIRING DIAGRAM WYE DELTA START LD03229 FIG 23 CONT D 7 ...
Page 66: ...66 YORK INTERNATIONAL FIG 23 CONTINUED ELEMENTARY DIAGRAM Technical Data ...
Page 68: ...68 YORK INTERNATIONAL FIG 24 POWER PANEL FRONT INSIDE VIEW WYE DELTA START Technical Data ...
Page 71: ...71 YORK INTERNATIONAL FORM 201 18 NM8 LD03282 LD03283 LD03284 FIG 27 DETAIL A 7 ...
Page 74: ...74 YORK INTERNATIONAL FIG 32 DETAIL B Technical Data LD03285 ...
Page 75: ...75 YORK INTERNATIONAL FORM 201 18 NM8 FIG 33 DETAIL C 7 3 4 5 6 7 8 5 6 3 4 7 8 9 10 LD06841 ...