Lennox SPBH4 Series, Unit Information

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Page 13
FIGURE 12
SCROLL
HOW A SCROLL WORKS
SUCTION
SUCTION
SUCTION
MOVEMENT OF ORBIT
STATIONARY SCROLL
ORBITING
CRESCENT
SHAPED GAS
POCKET
HIGH
PRESSURE
GAS
DISCHARGE
POCKET
FLANKS
SEALED BY
CENTRIFUGAL
FORCE
1 2
3
4
SUCTION
INTERMEDIATE
PRESSURE
GAS
SUCTION
POCKET
FIGURE 13
Bypass Ports
Closed
High Capacity
Bypass Ports
Open
Low Capacity
TWO−STAGE MODULATION
INTERNAL SOLENOID (L34)
The internal unloader solenoid controls the two−stage op-
eration of the compressor by shifting a slide ring mecha-
nism to open two by−pass ports in the first compression
pocket of the scrolls in the compressor. The internal sole-
noid is activated by a
24 volt direct current solenoid co i l.
The coil power requires 20VAC. The internal wires from the
solenoid in the compressor are routed to a 2 pin fusite con-
nection on the side of the compressor shell. The external
electrical connection is made to the compressor with a
molded plug assembly. This plug contains a full wave rectifi-
er that converts 24 volt AC into 24 volt DC power to power
the unloader solenoid. Refer to unit diagram for internal cir-
cuitry view of plug.
If it is suspect the unloader is not operating properly, check
the following