York YCAS Series, Installation Operation & Maintenance

Page: 181 / 216

181 YORK INTERNATIONAL
FORM 201.19-NM8 (804)
8
Local/Remote Communications
The panel can be programmed for “Local” or “Re mote”
communications. “Local” mode allows monitoring
through the RS-485 port only. “Remote,” allows an ex-
ter nal device such as an ISN or Remote Control Cen ter
to change setpoints and programming points.
The
!"
keys are used to change from Local to Re mote.
The ENTER Key must be pressed to save the selection
in memory.
Imperial/SI Units Display
This allows the operator to select messages to display
Imperial Units (PSIG, °F, etc.) or SI (Sci en tifi c Interna-
tional, Bars, °C, etc.).
The
!"
keys are used to change from Imperial to SI
units. The ENTER Key must be pressed to save the
selection in memory.
Automatic/Manual “Lead/Lag”
The chiller may be selected for manual lead/lag or au to -
mat ic lead/lag. In some cases the operator may want to
manually select the system that is desired to be the lead
system. In most cases, automatic lead/lag is se lect ed to
allow the micro to attempt to balance run time between
the system. Details of manual and automatic lead / lag
operation are outlined in Section 1.21.
The
!"
keys are used to change from Automatic to
Manual lead/lag. The ENTER key must be pressed to
save the selection in memory.
For the fi rst 60 seconds of operation, the unloading
control is disabled. After this time, if motor current
ex ceeds the programmed limit, the SYS X CURR
LIM IT ING mes sage will appear on the display and a
1 second unload pulse will be sent to the slide valve
of the af fect ed com pres sor every 5 seconds, until the
motor cur rent drops below the programmed limit. The
message will be re moved and additional loading will
take place when mo tor current drops below 90% of the
pro grammed thresh old.
Typically, this setpoint should be set at 100% for
maximum motor protection. Programming for 100%
is recommended. When programming values be low
100%, the use of a leading “0” is required, e.g. 085%.
To program the High Motor Current Unload, key in the
required setting and press the Enter key to store the value
into memory and scroll to the next display.
Anti-Recycle Time
The Anti-Recycle Timer controls the minimum time
between starts for each compressor. This is the time
available for the heat build-up caused by inrush current
at start to be dissipated before the next start. In suf fi cient
cooling time between starts can cause heat build-up
and motor damage. A fast compressor start re sponse
is needed in some applications and not in others. Al-
though the minimum setting allowed on this timer will
avoid excessive heat build up, adjusting the timer for
the longest period acceptable in each application will
reduce cycling and maximize motor life.
600 seconds
is recommended.
The micro will accept a range of programmable values
between 300 - 600 seconds.
To program the Anti-Recycle Time, key in the required
setting and press the Enter key to store the value into
memory and scroll to the next display.
The EEV superheat setpoint is programmable. The
setpoint can be programmed for 9.0ºF (5.0ºC) to 15ºF
(8.3ºC) with 12.0ºF (6.6ºC) as the default.
A N T I R E C Y C L E T I M E R
= 6 0 0 S E C S
L O C A L / R E M O T E M O D E
L O C A L
D I S P L A Y U N I T S
I M P E R I A L
L E A D / L A G C O N T R O L
A U T O M A T I C
S U C T I O N S U P E R H E A T
S E T P O I N T = 1 2 . 0 º F
Suction Superheat Setpoint