York YCAL0043E Series, Installation Operation & Maintenance

Page: 68 / 184

YORK INTERNATIONAL
68
FORM 150.62-NM7 (103)
S Y S 1 H I G H D S C H P R E S
S Y S 2 H I G H D S C H P R E S
S Y S 1 L O W S U C T P R E S S
S Y S 2 L O W S U C T P R E S S
When this message appears, suction pres sure limiting
is in effect. Suction Pressure Lim it ing is only available
on units that have the suction pressure trans duc er
in stalled. If a low pressure switch is installed instead,
suc tion pres sure limiting will not function.
The suction pressure limit is a control point that limits
the loading of a system when the suction pressure drops
to with in 15% above the suction pressure cutout. On a
stan dard system pro grammed for 44 PSIG/3.0 Bar suc-
tion pres sure cutout, the micro would inhibit loading of
the affected system with the suction pres sure less than
or equal to 1.15 * 44 PSIG/3.0 Bar = 50 PSIG/3.5 Bar.
The system will be allowed to load after 60 sec onds
and after the suction pres sure rises above the suc tion
pres sure limit point.
This message indicates that load limiting is in effect and
the percentage of the limiting in effect. This limiting could
be due to the load limit/pwm input, ISN or RCC con trol ler
could be sending a load limit command.
If MANUAL OVERRIDE mode is se lect ed, the STATUS
display will display this message. This will indicate that
the Daily Schedule is being ignored and the chiller will
start-up when chilled liquid temperature allows, Re mote
Con tacts, UNIT switch and SYSTEM switches per mit ting.
This is a priority message and can not be over rid den by
anti-recycle messages, fault mes sag es, etc. when in the
STATUS display mode. There fore, do not expect to see
any other STATUS mes sag es when in the MAN U AL
OVERRIDE mode. MANUAL OVER RIDE is to only be
used in emergencies or for ser vic ing. Man u al override
mode au to mat i cal ly dis ables it self af ter 30 min utes.
The PUMPING DOWN message indicates that a com-
pres sor in the respective system is pres ent ly in the pro-
cess of pumping the system down. When pumpdown
is initiated on shutdown, the liquid line so le noid or EEV
will close and a com pres sor will con tin ue to run. When
the suc tion pres sure de creas es to the suction pres sure
cutout setpoint or runs for 180 seconds, whichever
comes fi rst, the com pres sor will cy cle off.
FAULT STATUS MESSAGES
Safeties are divided into two categories – sys tem
safe ties and unit safeties. System safeties are faults
that cause the individual system to be shut down. Unit
safe ties are faults that cause all run ning compressors
to be shut down. Fol low ing are display mes sag es and
ex pla na tions.
System Safeties:
System safeties are faults that cause in di vid u al sys tems
to be shut down if a safety threshold is exceeded for 3
seconds. They are auto reset faults in that the system
will be allowed to restart automatically after the fault
con di tion is no longer present. However, if 3 faults on
the same system occur within 90 min utes, that system
will be locked out on the last fault. This condition is then
a manual reset. The system switch (under OPTIONS
key) must be turned off and then back on to clear the
lockout fault.
The Dis charge Pres sure Cutout is a soft ware cutout in
the mi cro pro ces sor and is backed-up by a me chan i cal
high pressure cutout switch located in the re frig er ant
cir cuit. It assures that the system pres sure does not
ex ceed safe work ing limits. The system will shut down
when the pro gram ma ble cutout is ex ceed ed and will be
al lowed to restart when the dis charge pres sure falls 40
PSIG be low the cutout.
Discharge trans duc ers must be
in stalled for this function to operate.
The Suction Pressure Cutout is a software cutout that
helps protect the chiller from an evap o ra tor freeze-up
should the system attempt to run with a low re frig er ant
charge or a re stric tion in the re frig er ant circuit.
Repeated starts after resetting a low suc-
tion pres sure fault will cause evap o ra tor
freeze-up. When ev er a sys tem locks out
on this safety, im me di ate steps should
be tak en to iden ti fy the cause.
At system start, the cutout is set to 10% of pro-
grammed value. During the next 3 minutes the cutout
point is ramped up to the pro grammed cutout point.
If at any time during this 3 minutes the suc tion pres-
sure falls below the ramped cut out point, the system
will stop.
S Y S 1 S U C T L I M I T I N G
S Y S 2 S U C T L I M I T I N G
S Y S 1 L O A D L I M I T X X %
S Y S 2 L O A D L I M I T X X %
M A N U A L
O V E R R I D E
S Y S 1 P U M P I N G D O W N
S Y S 2 P U M P I N G D O W N
Unit Controls