York YCAJ44HE8, Инструкция по установке, эксплуатации и обслуживанию, Страница: 36 / 92

36 YORK INTERNATIONAL
The micro will accept a range of programmable values
between 200-390 PSIG for the unload point. For this fea-
ture to be functional, the Discharge Pressure Read-out
Option must be installed.
NOTE: It is required to first key in a “0” when program-
ming this cut-out (Example: 0375 PSIG).
SUCTION PRESSURE UNLOAD
The SUCTION PRESSURE UNLOAD point is a program-
mable limit designed to assure that suction gas returning
to the compressor is cool enough to provide adequate
compressor cooling.
If the suction pressure rises to the suction pressure un-
load pressure, the micro will automatically totally unload
the affected compressor which reduces motor heating.
Reloading will occur when the suction pressure drops to
10 PSIG below the programmed unload pressure and will
increment one stage at a time as dictated by the loading
timers.
This safety will only come into action on a very hot water
start with related high system suction pressure. Its sole
purpose is to prolong motor life.
To program the SUCTION PRESSURE UNLOAD, key in
the desired value and press the ENTER key. The new
value will be entered into memory and the display will
advance to the next user programmable limit.
The micro will accept a range of programmable values
between 80-105 PSIG for the unload point.
NOTE: When programming values from 80-99 PSIG, it
is required to first key in a “0”. Example: 085
PSIG.
RATE CONTROL TEMP
The RATE CONTROL TEMP establishes a temperature
range over which the micro may override normal system
loading timers and react to the actual rate of change of
return and leaving water temperature. This temperature
range is slightly above the setpoint with its band width
being programmable. This control works in conjunction
with the RATE SENSITIVITY which is also program-
mable.
These controls allow the chiller to adapt to a full range of
applications. Depending on how the controls are set up,
the chiller can be adapted to provide maximum re-
sponse, demand limiting/energy saving, or reduced
loader and compressor cycling. Typically, this value
should be programmed for 00.1°F. When program-
ming values like 00.1°F, it is first required to key in
“00”. Example: 00.1°F. Additional details for program-
ming this control will be discussed in the SELECTION
OF RETURN OR LEAVING CHILLED LIQUID CONTROL
Section (Page 40).
ANTI RECYCLE TIME
The ANTI RECYCLE TIME selection allows the user to
select the compressor anti-recycle time to best suit his
needs. Motor heating is a result of inrush current when
the motor is started. This heat must be dissipated before
another start takes place or motor damage may result.
The anti-recycle timer assures the motor has sufficient
time to cool before it is again restarted.
An adjustable timer allows for the motor cooling required,
but gives the user the ability to extend the timer to cut
down on cycling. In some applications fast compressor
start response is necessary; in others, it is not. These
needs should be kept in mind and the timer should be
adjusted for the longest period of time tolerable. Al-
though 300 seconds is adequate motor cooling time,
longer periods will allow even more heat dissipation, re-
duce cycling, and possibly increase motor life.
To program the ANTI RECYCLE TIME, key in the desired
value and press the ENTER key. The new value will be
entered into memory and the display will advance to the
next user programmable limit.
The micro will accept a range of programmable values
between 300-600 seconds for this operating control.
LEAVING WATER TEMP CUT-OUT
The LEAVING WATER TEMP CUT-OUT protects the
chiller from an evaporator freeze-up should the chilled
liquid temp drop below the freeze point. This situation
could occur under low flow conditions or if the micro
panel SETPOINT values are improperly programmed.
Anytime the leaving chilled liquid temperature (water or
glycol) drops to the cut-out point, the chiller will shut
down. Restart will occur when temperature rises above
the cut-out if the anti-recycle timers are satisfied.
S U C T I O N P R E S S U R E
U N L O A D = 0 9 0 P S I G
R A T E C O N T R O L T E M P
= 0 8 . 0 F
A N T I R E C Y C L E T I M E
= 6 0 0 S E C S
L E A V I N G W A T E R T E M P
C U T O U T = 3 6 . 0 F