Trane 4TTZ0 Installer's Manual page 28

STEP 4 - Use the measured values from Step 3
to determine a target superheat of 15 degrees.
Example: Assume a suction pressure of 81
PSIG and a suction temperature of 36º F.
When the suction temperature is in line with
the suction gage pressure, the target superheat
value will be 15 degrees. (Example values high-
lighted in Table 13.2)
STEP 5 - Adjust refrigerant level to attain 15
degrees of superheat.
Add refrigerant if the suction line temperature
is above the value that is in line with the mea-
sured suction gage pressure.
1. Connect gages as shown in Step 3.
2. Purge all hoses.
3. Open bottle.
4. Stop adding refrigerant when the suc-
tion line temperature is in line with the
measured suction line pressure in Table
13.2.
Recover refrigerant if the suction line tempera-
ture is lower than the temperature that is in line
with the system's suction pressure.
28
Table 13.2
15 degree Superheat Chart
Suction Line Suction Gage
Temp Pressure
10 42
12 44
14 47
16 50
52
18
20 55
58
22
24 61
64
26
28 67
70
30
32 74
77
34
36 81
38 84
40 88
42 92
44 96
46 100
104
48
50 108
112
52
54 117
121
56
58 126
131
60
62 136
141
64
70 157
18-BC53D2-6