FORM 201.10-NM4
77
YORK INTERNATIONAL
System Switches OFF:
This message indicates that the system switch on the
Microprocessor Board for the respective system is in
the Off position. A system can only run if the system
switch is in the On position. The switch for System 1
and System 2 should normally be in the On position for
all models. Switches for System 3 and 4 should only be
in the On position for three or four compressor chillers
respectively. See Section 1.8, page 71, for the location
of the system switches.
Anti-Recycle Timers:
The anti-recycle timer message shows the amount of
time left before a compressor can be called to restart.
These 300 - 600 second timers begin timing when a
compressor starts, although a minimum of two minutes
must always elapse after a compressor shuts down
before it may again restart. If a power failure occurs,
the anti-recycle timers will reset to 120 seconds after
power is restored.
Anti-Coincidence Timers:
The anti-coincident timer guards against two or more
compressors starting simultaneously. This avoids ex-
cessive instantaneous starting currents. A minimum of
one minute between compressor starts is maintained
even if demand is present and the anti-recycle timers
are timed out. The display shows the time before the
respective compressor can start. This display will only
appear after the anti-recycle timers have timed out.
Run Permissive Contacts OPEN:
This display indicates that an external cycling contact and/
or the flow switch connected to Terminals 13 & 14 in the
Logic Section(s) of the control panel(s) is/are open. When-
ever the contact(s) is/are open, the No Run Permissive
message will be displayed, and the indicated system will
not run.
System Loading Requirement:
This message indicates that the chilled liquid tempera-
ture is below the point where the microprocessor will
bring the lead system on and/or that the loading se-
quence has not loaded the chiller far enough to bring
the lag system on. The lag system will display this mes-
sage until the loading sequence is ready for the lag sys-
tem to start.
Refrigerant Program Mismatch:
This message indicates that the type of refrigerant pro-
grammed under the Program key does not match the
type of refrigerant selected on the S1 Dip Switches on
the Microprocessor Board. The chiller will not operate
until this situation is corrected. See Section 3.7 and 8.2
for more details.
NOTE: It is extremely important that the programmed
settings correspond to the type of refrigerant used
in the chiller or serious damage may occur.
Pumpdown Cycle:
Each compressor undergoes a pump down cycle on
start-up and shutdown. This assures that liquid refrig-
erant does not enter the compressor on start-up, elimi-
nating the need for recycling pump down, saving en-
ergy and reducing compressor starts and wear.
On start-up, the controls unload the compressor and
the system either pumps down to the low suction pres-
sure cutout setting, or for 30 seconds, whichever comes
first, after which the Liquid Line Solenoid Valve and
Economizer / Motor Cooling Liquid Supply Solenoid
Valve are energized and normal operation commences.
On shutdown, the microprocessor controls unload the
compressor, and the Liquid Line Solenoid Valve and
Economizer / Motor Cooling Liquid Supply Solenoid
Valve are de-energized. The compressor continues to
operate until it either pumps down to the low suction
pressure cutout setting or operates for 30 seconds,
whichever comes first. Pump down occurs on normal
shutdowns where cooling demand has been satisfied
or when a system is turned off, a flow switch opens, a
run permissive is lost or a Daily Schedule or a Remote
Shutdown is called for.
The pumping down display is only shown when a cool-
ing demand shutdown, micro board system switch shut-
down, or a run permissive / flow switch shutdown oc-
curs. After pump down is complete, the respective shut-
down message will be displayed for the system.
S Y S
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S Y S
S W I T C H
O F F
S Y S
#
S Y S
S W I T C H
O F F
S Y S
#
A R
T I M E R
0
S
S Y S
#
A R
T I M E R
1 2 0
S
S Y S
#
C O M P
R U N N I N G
S Y S
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A C
T I M E R
2 2
S
S Y S
#
N O
R U N
P E R M
S Y S
#
N O
R U N
P E R M
S Y S
#
N O
C O O L
L O A D
S Y S
#
N O
C O O L
L O A D
P R O G R A M
T Y P E
O F
R E F R I G E R A N T
T O
R U N
S Y S
#
P U M P I N G
D O W N
S Y S
#
P U M P I N G
D O W N
