 |
|||
|
|
|||
|
|
|||
| ||||||||||
|
|
 TM 5-4110-217-14
1.
Tube
26.
Bracket
50.
Pan
75.
Washer, lock
2.
Elbow
27.
Valve, expansion
51.
Rivet, pop, 3/16 Alum.
76.
Nut, hex
3.
Heat Exchanger
28.
Distributor
52.
Elbow
77.
Tube
4.
"U" Bolt
29.
Tube
53.
Tube
78.
Elbow
5.
Washer, lock
30.
Elbow
54.
Clamp
79.
Tube
6.
Nut
31.
Tube
55.
Tube
80.
Elbow
7.
Clamp
32.
Elbow
56.
Elbow
81.
Tube
8.
Screw
33.
Tube
57.
Clamp
82.
Valve, solenoid
9.
Nut
33A.
Tube
58.
Tube
83.
Indicator, liquid. (sight. gauge)
10.
Washer
34.
Fitting
59.
Clamp
84.
Tube
11.
Thermostat
35.
Bracket
60.
Screw
85.
Valve, solenoid
12.
Tube
36.
Screw
61.
Washer, lock
86.
Tube
13.
Connector
37.
Elbow
62.
Nut, hex
87.
Tee
14.
Tube
38.
Tube
63.
Clamp
88.
Tube
15.
Elbow
39.
Elbow
64.
Washer, lock
89.
Tube
16.
Tube
40.
Tube
65.
Nut, hex
90.
Valve, hand, liquid
17.
Elbow
41.
Elbow
66.
Clamp
91.
Screw
18.
Fitting
42.
Tube
67.
Washer, lock
92.
Washer, lock
19.
Evaporator
43.
Elbow
68.
Nut, hex
93.
Nut, hex
20.
Screw
44.
Tube
69.
Strainer, hot gas line
94.
Tube
21.
Washer
45.
Elbow, reducer
70.
Tube
95.
Strainer, dehydrator
22.
Elbow
46.
Tube
71.
Elbow
96.
Tube
23.
Tube
47.
Elbow
72.
Tube
97.
Tube
24.
Elbow
48.
Tube
73.
Valve, hand, hot gas
98.
Panel
25.
Tube
49.
Elbow
74.
Screw
99.
Rivet, pop
Figure 6-3. - Continued
Section V. EXPANSION VALVE
6-18.
General.
the thermo bulb.
Any increase in suction line
temperature causes the gas in the thermo bulb to
The expansion valve acts as a pressure-sensitive
expand and the diaphragm then forces the valve plunger
variable restriction between the high and low pressure
away from the orifice, allowing refrigerant to enter the
sides of the refrigeration system. The flow of refrigerant
evaporator. The expansion valve is preset by the
through the valve is controlled by the opening and
manufacturer to maintain a balance when the
closing movement of a plunger connected to the
temperature of the thermo bulb is approximately 400 to
diaphragm of the expansion valve. The coupled plunger
50F above the temperature of refrigerant entering the
and diaphragm are acted upon by two forces. The
evaporator. 6-19. Expansion Valve. (Fig. 6-3).
pressure of the liquid in the bulb of the expansion valve
6-19. Expansion Valve. (Fig. 6-3.) a. Adjusting.
causes a downward or opening movement on the
diaphragm and plunger.
The valve plunger and
(1) Remove panel (2, fig. 3-23) at rear of
diaphragm are spring-loaded to assist the evaporator
evaporator section.
pressure to cause an upward or closing movement. A
(2) Remove superheat adjustment cap and turn
gas-filled thermo bulb is clamped to the evaporator outlet
square adjusting stem only turn at a time. Turning
line and connected to the diaphragm by means of a
stem to right decreases flow and raises superheat.
capillary tube. When the evaporator is refrigerated and
Turning stem to left increases flow and lowers superheat.
the thermo bulb is cold, the gas in the bulb contracts and
The superheat is correctly adjusted when the suction line
the pressure on the diaphragm decreases in direct
at the expansion valve thermo bulb is 10F warmer than
proportion. As pressure on the diaphragm
the saturated refrigerant in the coil.
decreases, the plunger spring in the valve housing
(3) Replace adjustment cap.
forces the plunger against the valve orifice, shutting
(4) Replace panel at rear of evaporator section.
b. Removal.
off the flow of refrigerant to the evaporator. An external
equalizer line connects a chamber under the valve
(1) Refer to paragraph 6-1 and pump down
diaphragm to the suction line, which enables the
refrigeration system.
expansion valve to make an accurate reading of and
response
to
the
suction
pressure
at
6-11
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals