Amana P1172401C, Руководство по обслуживанию

Страница: 193 / 243

193 Rev. 3
SERVICING
S-111 CAPILLARY TUBES
The capillary tubes used in conjunction with the indoor and
outdoor coil, are a predetermined length and bore (I.D.).
They are designed to control the rate of liquid refrigerant flow
into an evaporator coil.
The amount of refrigerant that flows through the capillary tubes
is regulated by the pressure difference between the high and
low sides of the system.
In the cooling cycle when the outdoor air temperature rises,
the high side condensing pressure rises. At the same time,
the cooling load on the indoor coil increases, causing the low
side pressure to rise, but at a slower rate.
Since the high side pressure rises faster when the tempera-
ture increases, more refrigerant flows to the evaporator, in-
creasing the cooling capacity of the system.
When the outdoor temperature falls, the reverse takes place.
The condensing pressure falls, and the cooling loads on the
indoor coil decrease, causing less refrigerant flow.
A strainer is placed on the entering side of the tubes to pre-
vent any foreign material from becoming lodged inside the
capillary tubes.
If a restriction should become evident, proceed as follows:
1. Capture the refrigerant charge.
2. Remove the capillary tubes or tube strainer assembly and
replace.
3. Replace liquid line drier, evacuate and recharge.
CHECKING EQUALIZATION TIME
During the "OFF" cycle, the high side pressure bleeds to the
low side through the capillary tubes. Check equalization time
as follows:
1. Attach a gauge manifold to the suction and liquid line dill
valves.
2. Start the system and allow the pressures to stabilize.
3. Stop the system and check the time it takes for the high
and low pressure gauge readings to equalize.
If it takes more than seven (7) minutes the capillary tubes are
inoperative. Replace, install a liquid line drier, evacuate and
recharge.
S-112 CHECKING RESTRICTED LIQUID LINE
When the system is operating, the liquid line is warm to the
touch. If the liquid line is restricted, a definite temperature
drop will be noticed at the point of restriction. In severe cases,
frost will form at the restriction and extend down the line in
the direction of the flow.
Discharge and suction pressures will be low, giving the ap-
pearance of an undercharged unit. However, the unit will
have normal to high subcooling.
TEMPERATURE - PRESSURE (R-22)
Temp.
°F.
Gauge Pressure
(PSIG) Freon-22
Temp.
°F.
Gauge Pressure
(PSIG) Freon-22
-40
-38
-36
-34 0.61
1.42
2.27
3.15 60
62
64
65 102.5
106.3
110.2
114.2
-32
-30
-28
-26 4.07
5.02
6.01
7.03 68
70
72
74 118.3
122.5
126.8
131.2
-24
-22
-20
-18 8.09
9.18
10.31
11.48
76
78
80
82 135.7
140.5
145.0
149.5
-16
-14
-12
-10 12.61
13.94
15.24
16.59 84
86
88
90 154.7
159.8
164.9
170.1
-8
-6
-4
-2 17.99
19.44
20.94
22.49 92
94
96
96 175.4
180.9
186.5
192.1
0
2
4
6 24.09
25.73
27.44
29.21 100
102
104
106 197.9
203.8
209.9
216.0
8
10
12
14
31.04
32.93
34.88
36.89 108
110
112
114 222.3
228.7
235.2
241.9
16
18
20
22 38.96
41.09
43.28
45.53 116
118
120
122 248.7
255.6
262.6
269.7
24
26
28
30 47.85
50.24
52.70
55.23 124
126
128
130 276.9
284.1
291.4
298.8
32
34
36
38 57.83
60.51
63.27
66.11 132
134
136
136 306.3
314.0
321.9
329.9
40
42
44
46 69.02
71.99
75.04
78.18 140
142
144
146 338.0
346.3
355.0
364.3
48
50
52
54 81.40
84.70
88.10
91.5
158
150
152
154 374.1
384.3
392.3
401.3
56
58 95.1
98.8
156
158
160 411.3
421.8
433.3
If a restriction is located, replace the restricted part, replace
drier, evacuate and recharge.