12
13.1
56
52.3
14
14.4
60
57.5
16
15.7
64
62.7
18
17
68
68.3
20
18.4
72
74.2
22
19.9
76
80.3
24
21.4
80
86.8
26
22.9
84
93.6
28
24.5
88
100.7
30
26.1
92
108.2
32
27.8
96
116.1
34
29.5
100
124.3
Table A
During production cycle, low side pressures will vary from 125 psi to 3 psi, depending at
what point measurements are taken. High side pressure can range from 425 psi to 25 psi
also depending at what point measurements are taken
In evaluating this system, the best point to determine if pressures are correct is at the end
of the production cycle. This is the point where there is a thick slab formed on the
evaporator and the evaporator thermostat is near cut-out temperature. Using Table A, use
temperature to convert to a corresponding pressure.
If low side pressure is below pressure in Table A, check for the following:
1. A system leak
2. Capillary tube is restricted
3. Insufficient compressor
If low side pressure is above pressure in Table A, check for the following:
1. Restricted air flow
2. Dirty condenser coil
3. Leaking or energized hot gas valve
4. Overcharged system
5. Low side leak
2.7 Recharging
Recharging of the unit should be done only after diagnosing and repairing the
system (see Sealed System introduction).
Be sure to flush the system with dry nitrogen
gas and evacuate to 50 microns before re-charging.
The method for recharging the unit is by weight using vapor refrigerant.
Using
manifold gage setup, hook up charge hoses to the access valve on the compressor’s
process tube. If any access valve was attached to the high side process tube, remove it
and seal the tube by brazing before charging. Charge the unit to 5.0 oz (0.313 lbs.) of
R134A.
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