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Crusader
MC-8
MAINTENANCE
[,.o,_1_6_-_ll _ _
oArE_Ma_rc_h_,
1_97_6_] ·
MANUAL
CAUTION: It is essential that only the correct
lubricant be used, such as Capella DI or equivalent.
There are three solenoid valves
(I)
Unloader,
(1)
Scavenger and
(I)
Capacity Control, are mounted to
one bracket at the front of the A/C compressor
mount.
Unloader Valve: Its function is to control oil flow
to the unloader power elements of two cylinders of
the A/C compressor.
a)
When the valve is at "Current Off', the valve
opens and the A/C compressor remains unloaded.
b) When the valve is at "Current On", the valve
closes and the A/C compressor is loaded.
CAPACITY CONTROL VALVE: When the valve is
at "Current Off", the valve opens and the third cylinder
of A/ C compressor is unloaded. When the valve is at
"Current On", the valve closes and the third cylinder of
the compressor is loaded and resumes operation.
SCA YEN GER VAL YE: A scavenger valve prevents
the possibility of oil migration from the compressor
crankcase during the unloaded cycle.
When the compressor is in the "OFF" cycle or
unloaded, any oil bypassing the piston rings and
carried over into the cylinder head is returned to the
crankcase by the scavenge line.
The scavenge system is operated by a normally
open solenoid valve. When the compressor is turned
on, the solenoid is energized and closes the line from
the cylinder head side to the crankcase. This prevents
bypassing of compressed gas into the crankcase.
In case of solenoid valve failure, the amount of gas
passing through the .046 restrictor is not detrimental
although it will decrease the capacity of the system.
When the compressor is in a pumping cycle or
loaded, there is enough volume of refrigerant to
return the oil to the crankcase during the normal
cycle.
During the pumping cycle there is
less
Coi I & Housing
Assembly
_ _ _ Plunger & Enclosing
Tube Assembly
·<::>_;-..-
"O" Ring
~
Body Assemb I y
&-.
Body Screws
Figure 16-13: Solenoid Valve
Disassembled
T -
Coi I Retaining Nut
~
Identification Plate
Housing
Sleeve
~ S p r i n g
Coil
Sleeve
. Bottom Plate
Figure 16-14: Solenoid Coil
Disassembled
tendency for oil to migrate past the piston rings due
to the normal compression pressure.
All Freon solenoid valves are normally open units.
When current is applied to the coil, the plunger
travels down and closes the port in the base of the
cylinder valve.
Note: Care must be taken to insure that the valve is
installed with the flow arrow in the proper direction.
If a problem is located in the mechanical portion of
the valve, the coil assembly may be removed and
moved away from the valve during repairs without
disconnecting the wires.
Similarly, if the problem is electrical, the coil can
be moved away from the valve assembly and repaired
without interfering with the refrigerant fittings.
DISASSEMBLY
There are lour parts to the solenoid valve. These are:
coil and housing assembly, plunger and enclosing tube
assembly, "O" ring and valve body.
To remove the solenoid coil, first unscrew the retain-
ing screw at the top ol the coil housing. The entire coil
assembly can then be lifted off the enclosing tube.
To disassemble the valve. unscrew the two socket-
head body screws which hold the body and bonnet to-
gether. After removing the screws, carefully lift off the
bonnet assembly (upper part of the valve). Be careful
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