52
YORK INTERNATIONAL
Oil Pressure Safety
The Oil Pressure Safety assures that the compressors
mechanical components receive proper lubrication. The
micro begins monitoring compressor oil pressure after 4
seconds of operation. For operating periods of 4 seconds
to 30 seconds, oil pressure must be greater than 5 PSID.
From 30 seconds to 240 seconds, oil pressure must be
greater than 20 PSID. After 240 seconds, oil pressure
must be greater than 25 PSID for as long as the com-
pressor continues to run. If the required oil pressure lim-
its are not met, the system will shut down.
The micro computes differential oil pressure by meas-
uring oil pump pressure and subtracting suction pres-
sure (Oil - Suction = Oil PSID).
An example of an oil pressure fault display message is
shown below.
Discharge Pressure Safety
The Discharge Pressure Safety assures that the system
pressure does not exceed safe working limits which
could open a relief valve or other pressure relief device
causing refrigerant loss.
This safety is a back-up for the mechanical safety in the
system. Anytime the cut-out point is exceeded, the sys-
tem will shut down.
The Discharge Pressure Safety Cut-out is programmable
by the user (Page 34). An example of a discharge pres-
sure fault display message is shown below.
NOTE: This safety is only operable if optional discharge
pressure transducers are installed.
Pumpdown Safety
The Pumpdown Safety assures that a compressor does
not run unless it completes a proper pumpdown. This
prevents operation of a refrigerant system which has a
leaking liquid line solenoid valve.
On start-up, the system must pump down to the suction
pressure cut-out within 300 seconds or the system will
shut down.
An example of the Pump down fault display message is
shown below.
NOTE: LLSV refers to liquid line solenoid valve.
Motor Protector
Three internal temperature sensors are built into the mo-
tor stator. These sensors are wired into the motor protec-
tor module located inside the Motor terminal box. As the
motor windings heat and cool, the resistance of the mo-
tor temperature sensors will change . If the windings
overheat, the change in resistance in the sensors will be
sensed by the Motor protector module. The module will
open its MP contacts breaking the 115VAC fed to the
motor contactor. When the motor contactor
de-energizes, motor current falls to zero. The low motor
current is sensed by the microprocessor and the system
is shut down. For more information, see MOTOR CUR-
RENT SAFETY (Page 51).
Auto-restart will be permitted after a shutdown, when the
motor sensors cool and the MP contacts close. A fault
lock-out will result if safety thresholds are exceeded
three times in a 90 minute period.
Mechanical High Pressure Cut-out (HPCO)
A mechanical high pressure cut-out is located on each
compressor discharge or in the compressor head. This
is the primary high pressure safety in the system. Any
microprocessor controls are secondary.
Anytime discharge pressure exceeds 405 PSIG, the
contacts in the high pressure cut-out will open which re-
moves 115VAC from the motor protector module. When
115VAC control power is lost to the module, the
modules MP contacts open breaking the 115VAC fed to
the motor contactor. The motor contactor de-energizes
and motor current falls to zero. The low motor current is
sensed by the microprocessor and the system is shut
down. For more information see MOTOR CURRENT
SAFETY (Page 51).
Auto-restart will be permitted after a shutdown when dis-
charge pressure drops to below 330 PSIG which allows
the mechanical high pressure cut-out to reset and its
contacts to close. This re-applies 115VAC to the motor
protector closing the MP contact. A fault lock-out will
result if safety thresholds are exceeded three times in a
90 minute period.
S Y S # 1
L O W
S U C T I O N
S Y S # 2
L O W
S U C T I O N
S Y S # 1
L L S V
N O T
O N
S Y S # 2
L L S V
N O T
O N
S Y S # 1
L O W
O I L
P R E S S
S Y S # 2
L O W
O I L
P R E S S
S Y S # 1
H I G H
D S C H
S Y S # 2
H I G H
D S C H
Содержание YCAJ44HE8
Страница 16: ...16 YORK INTERNATIONAL WIRING DIAGRAMS LD02165 FIG 5 ELEMENTARY DIAGRAM...
Страница 17: ...FORM 150 60 NM3 17 YORK INTERNATIONAL FIG 5 ELEMENTARY DIAGRAM Cont d LD02166...
Страница 20: ...20 YORK INTERNATIONAL CONNECTION DIAGRAM ELECTRICAL BOX FIG 7 CONNECTION DIAGRAM LD02171...
Страница 21: ...FORM 150 60 NM3 21 YORK INTERNATIONAL FIG 7 CONNECTION DIAGRAM Cont d LD02172...