
FORM 150.60-NM4
YORK INTERNATIONAL
69
LD02095
LD02096
UNLOADING
When the solenoid valve is energized, discharge gas pres-
sure is applied to the top of the unloader piston, forcing
it down against spring pressure. The bottom end of the
piston seats against the recessed opening to the suc-
tion plenum, effectively blocking the flow of suction gas
into the cylinders (blocked suction unloading). The cyl-
inders are now unloaded.
LOADING
When the solenoid valve is de-energized, gas pressure
on top of the unloader piston is relieved to the suction
plenum. The coil spring forces the piston up, uncovering
the recessed opening which allows the suction gas to
flow through the port and into the cylinders. The cylin-
ders are now loaded.
Z COMPRESSOR (STYLE B)
LOADING /UNLOADING
An external line, connected to the discharge side of the
compressor, supplies high pressure gas to the unloader
mechanism which is mounted next to the associated
bank of cylinders. The unloader mechanism consists of
a solenoid valve integrally mounted on the outside of the
cover plate, and an internal spring loaded piston.
NOTE: 6 cylinder compressors do not connect the loading sole-
noid wiring on cylinders 1 & 2, effectively making them
permanently loaded in the standard unloading scheme.
The loading solenoid wiring on these cylinders is con-
nected to additional electronics for extra steps of unload-
ing. Currently, extra steps of unloading are not available.
Cylinders 3 & 4 have no loading solenoids and are truly
permanently loaded.
FIG. 27
Z COMPRESSOR UNLOADING SEQUENCE
NOTE: 6 cylinder compressors do not connect the loading sole-
noid wiring on cylinders 1 & 2, effectively making them
permanently loaded in the standard unloading scheme.
The loading solenoid wiring on these cylinders is con-
nected to additional electronics for extra steps of unload-
ing. Currently, extra steps of unloading are not available.
Cylinders 3 & 4 have no loading solenoids and are truly
permanently loaded.
FIG. 28
J COMPRESSOR UNLOADING SEQUENCE
JCOMPRESSOR (STYLE G)
LOADING/UNLOADING
An internal line, connected to the discharge side of the
compressor, supplies high pressure gas to the unloader
mechanism which is mounted next to the associated
bank of cylinders. The unloader mechanism consists of
a solenoid valve integrally mounted on the outside of the
cover plate, and an internal spring loaded piston.
UNLOADING
When the solenoid valve is energized, discharge gas pres-
sure is applied to the top of the unloader piston, forcing
it down against spring pressure. The bottom end of the
piston seats against the recessed opening to the suc-
tion plenum, effectively blocking the flow of suction gas
into the cylinders (blocked suction unloading). The cyl-
inders are now unloaded.
LOADING
When the solenoid valve is de-energized, gas pressure
on top of the unloader piston is relieved to the suction
plenum. The coil spring forces the piston up, uncovering
the recessed opening which allows the suction gas to
flow through the port and into the cylinders. The cylin-
ders are now loaded.