YORK INTERNATIONAL
70
FORM 150.62-NM7 (103)
This safety can be triggered by two events. The fi rst is
when suction superheat <2.0°F for 3 seconds. The sec ond
is when the EEV pilot solenoid is closed 10 times in 2
min utes due to low su per heat.
The Sensor Failure Safety prevents the system from
run ning when the sensors measuring superheat are not
func tion ing properly. This safety is only active when EEV
is selected as the expansion valve type in SERVICE
Mode. This safe ty is ignored for the fi rst 15 sec onds of
system runtime.
This safety will shut down a system if either suction
tem per a ture or suction pressure sensors read out of
range high or low. This condition must be present for
3 sec onds to cause a system shutdown. The safety
locks out a system after the fi rst fault and will not allow
automatic restarting.
Unit Safeties:
Unit safeties are faults that cause all running com pres -
sors to be shut down. Unit faults are auto reset faults in
that the unit will be allowed to restart automatically after
the fault con di tion is no longer present.
The Low Ambient Temp Cutout is a safety shutdown
de signed to protect the chiller from operating in a low
am bi ent condition. If the outdoor ambient tem per a ture
falls below the pro gram ma ble cutout, the chill er will shut
down. Restart can occur when tem per a ture ris es 2°F
above the cutoff.
The Low Leaving Chilled Liquid Temp Cutout protects
the chiller form an evaporator freeze-up should the
chilled liquid temperature drop below the freeze point.
This sit u a tion could occur under low fl ow con di tions or
if the mi cro panel setpoint values are im prop er ly pro-
grammed. Any time the leaving chilled liquid tem per a ture
(water or gly col) drops below the cutout point, the chiller
will shut down. Restart can occur when chilled liquid tem-
per a ture rises 2°F above the cutout.
The Under Voltage Safety assures that the system is
not operated at voltages where malfunction of the mi-
cro pro ces sor could result in system damage. When the
115VAC to the micro panel drops below a certain lev el, a
unit fault is initiated to safely shut down the unit. Re start
is allowed after the unit is fully powered again and the
anti-recycle timers have fi nished count ing down.
When the CURRENT FEEDBACK ONE PER UNIT op-
tion is selected under the OPTIONS Key, the unit will
shut down when the voltage exceeds the pro grammed
trip voltage for 5 seconds.
The trip voltage is programmed at the factory ac cord ing
to com pres sor or unit RLA.
Restart will occur after the anti-recycle timer times
out.
UNIT WARNING
The following messages are not unit safeties and will
not be logged to the history buffer. They are unit warn-
ings and will not auto-restart. Op er a tor in ter ven tion is
re quired to al low a restart of the chiller.
The Low Battery Warning can only occur at unit
power-up. On micro panel power-up, the RTC battery
is checked. If a low battery is found, all programmed
setpoints, pro gram values, options, time, sched ule, and
history buff ers will be lost. These values will all be reset
to their default values which may not be the desired op er -
at ing values. Once a faulty battery is detected, the unit
will be pre vent ed from running until the PRO GRAM key
is pressed. Once PROGRAM is pressed the anti-re cy cle
timers will be set to the pro grammed anti-re cy cle time to
allow the op er a tor time to check setpoints, and if neces-
sary, reprogram programmable values and options.
If a low battery is detected, it should be re placed as
soon as possible. The programmed values will all be
lost and the unit will be prevented from running on the
next power interruption. The RTC/battery is located at
U17 on the microboard.
U N I T F A U L T :
L O W A M B I E N T T E M P
U N I T F A U L T :
1 1 5 V A C U N D E R V O L T A G E
U N I T F A U L T :
L O W L I Q U I D T E M P
! ! L O W B A T T E R Y ! !
C H E C K P R O G / S E T P / O P T N
Unit Controls
U N I T F A U L T :
H I G H M T R C U R R
S Y S 1 S E N S O R F A I L U R E
S Y S 2 S E N S O R F A I L U R E
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