Page 11
1
2
3
4
SUCTION
SUCTION
ORBITING SCROLL
STATIONARY SCROLL
SUCTION
SUCTION
DISCHARGE
SUCTION
INTERMEDIATE PRESSURE
GAS
CRESCENT
SHAPED
GAS POCKET
HIGH PRESSURE GAS
FLANKS SEALED
BY CENTRIFUGAL
FORCE
MOVEMENT OF ORBIT
FIGURE 13
The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (figure
13 − 1). The centrifugal action of the orbiting scroll seals off the
flanks of the scrolls (figure 13 − 2). As the orbiting motion contin-
ues, the gas is forced toward the center of the scroll and the
gas pocket becomes compressed (figure 13 − 3). When the
compressed gas reaches the center, it is discharged vertically
into a chamber and discharge port in the top of the compressor
(figure 12). The discharge pressure forcing down on the top
scroll helps seal off the upper and lower edges (tips) of the
scrolls (figure 12). During a single orbit, several pockets of gas
are compressed simultaneously providing smooth continuous
compression.
The scroll compressor is tolerant to the effects of liquid return. If
liquid enters the scrolls, the orbiting scroll is allowed to separate
from the stationary scroll. The liquid is worked toward the cen-
ter of the scroll and is discharged. If the compressor is re-
placed, conventional Lennox cleanup practices must be used.
Due to its efficiency, the scroll compressor is capable of draw-
ing a much deeper vacuum than reciprocating compres-
sors. Deep vacuum operation can cause internal fusite
arcing resulting in damaged internal parts and will result
in compressor failure. Never use a scroll compressor for
evacuating or pumping−down" the system. This type of
damage can be detected and will result in denial of war-
ranty claims.
The scroll compressor is quieter than a reciprocating com-
pressor, however, the two compressors have much differ-
ent sound characteristics. The sounds made by a scroll
compressor do not affect system reliability, performance,
or indicate damage.
C − Outdoor Fan Motor (B4)
All units use single−phase PSC fan motors which require a run
capacitor. In all units, the condenser fan is controlled by
the compressor contactor.
ELECTRICAL DATA tables in this manual show specifi-
cations for condenser fans used in XP14’s.
Access to the condenser fan motor on all units is gained
by removing the four screws securing the fan assembly.
See figure 14. The grill fan assembly can be removed
from the cabinet as one piece. See figure 15. The con-
denser fan motor is removed from the fan guard by re-
moving the four nuts found on top of the grill. See figure
15 if condenser fan motor replacement is necessary.
Make sure all power is disconnected before
beginning electrical service procedures.
DANGER
FIGURE 14
Remove
screws
Remove
screws
