Fault Safety Status Messages - York YCAL0019 Installation, Operation And Maintenance Manual

SECTION 7 – UNIT CONTROLS
S Y S 1 A R
S Y S 2 A R
The anti-recycle timer message shows the amount of
time left on the respective systems anti-recycle timer.
This message is displayed when the system is unable to
start due the anti-recycle timer being active.
S Y S 1 A C
S Y S 2 A C
The anti-coincidence timer is a software feature that
guards against 2 systems starting simultaneously. This
assures instantaneous starting current does not become
excessively high due to simultaneous starts. The mi-
croprocessor limits the time between compressor starts
to 1 minute regardless of demand or the anti-recycle
timer being timed out. The anti-coincidence timer is
only present on two system units.
S Y S 1 D S C H
S Y S 2 D S C H
When this message appears, discharge pressure limit-
ing is in effect. The Discharge Pressure Limiting fea-
ture is integral to the standard software control; howev-
er the discharge transducer is optional on some models.
Therefore, it is important to keep in mind that this con-
trol will not function unless the discharge transducer is
installed in the system.
The limiting pressure is a factory set limit to keep the
system from faulting on the high discharge pressure
cutout due to high load or pull down conditions. When
the unload point is reached, the microprocessor will
automatically unload the affected system by de ener-
gizing one compressor. The discharge pressure unload
will occur when the discharge pressure gets within 10
PSIG (0.69 barg) of the programmed discharge pres-
sure cutout. This will only happen if the system is fully
loaded and will shut only one compressor OFF. If the
system is not fully loaded, discharge limiting will not
go into effect. Reloading the affected system will oc-
cur when the discharge pressure drops to 85% of the
unload pressure and 10 minutes have elapsed.
S Y S 1 S U C T
S Y S 2 S U C T
When this message appears, suction pressure limit-
ing is in effect. The suction pressure limit is a control
point that limits the loading of a system when the suc-
tion pressure drops to within 15% above the suction
pressure cutout. On a standard system programmed
156
T I M E R X X S
T I M E R X X S
T I M E R X X S
T I M E R X X S
L I M I T I N G
L I M I T I N G
L I M I T I N G
L I M I T I N G
for 44 PSIG (3.0 Bar) suction pressure cutout, the
microprocessor would inhibit loading of the affected
system with the suction pressure less than or equal to
1.15 times 44 PSIG (3.0 Bar), which equals 50 PSIG
(3.5 Bar). The system will be allowed to load after 60
seconds and after the suction pressure rises above the
suction pressure load limit point.
S Y S 1 L O A D
S Y S 2 L O A D
This message indicates that load limiting is in effect
and the percentage of the limiting in effect. This limit-
ing could be due to the load limit/PWM input, ISN or
RCC controller sending a load limit command.
M A N U A L
O V E R R I D E
If MANUAL OVERRIDE mode is selected, the STA-
TUS display will display this message. This will indi-
cate that the Daily Schedule is being ignored and the
chiller will start-up when chilled liquid temperature
allows, Remote Contacts, Unit Switch and System
Switches permitting. This is a priority message and
cannot be overridden by anti-recycle messages, fault
messages, etc. when in the STATUS display mode.
Therefore, do not expect to see any other STATUS
messages when in the MANUAL OVERRIDE mode.
MANUAL OVERRIDE is to only be used in emergen-
cies or for servicing. Manual override mode automati-
cally disables itself after 30 minutes.
S Y S 1 P U M P I N G
S Y S 2 P U M P I N G
The PUMPING DOWN message indicates that a com-
pressor in the respective system is presently in the pro-
cess of pumping the system down. When pumpdown is
initiated on shutdown, the liquid line solenoid or EEV
will close and a compressor will continue to run. When
the suction pressure decreases to the suction pressure
cutout setpoint or runs for 180 seconds, whichever
comes first, the compressor will cycle OFF.

Fault Safety Status Messages

Safety Status messages appear when safety thresholds
in the unit have been exceeded. Safeties are divided
into two categories – System Safeties and Unit Safe-
ties. System safeties are faults that cause the individual
system to be shut down. Unit safeties are faults that
cause all running compressors to be shut down. Fol-
lowing are display messages and explanations.
FORM 150.67-NM1
ISSUE DATE: 4/28/2017
L I M I T X X %
L I M I T X X %
D O W N
D O W N
JOHNSON CONTROLS