Lennox 13ACX Installation And Service Procedure page 32

START: Measure outdoor ambient temperature
USE WEIGH‐IN METHOD
Weigh‐in or remove refrigerant
based upon line length
SUPERHEAT RFC
If refrigerant is
REMOVED, retest to
confirm that unit is
properly charged.
If value is LESS than
shown, then REMOVE
refrigerant.
°F
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
ABOVE or
BELOW
40ºF
(4.4ºC) and
Above
See Table 4 on page 33 to determine
which charging sticker to use.
MORE or
LESS
Figure 22. HFC-410A Superheat RFC Method
Table 3. HFC-410A Temperature — Pressure (Psig)
°C Psig
-40.0 11.6
-37.2 14.9
-34.4 18.5
-31.7 22.5
-28.9 26.9
-26.1 31.7
-23.3 36.8
-20.6 42.5
-17.8 48.6
-15.0 55.2
-12.2 62.3
-9.4 70.0
-6.7 78.3
-3.9 87.3
-1.1 96.8
1.7 107
4.4 118
7.2 130
10.0 142
12.8 155
1. Confirm proper airflow across coil using figure 17.
39ºF
2. Compare unit pressures with normal operating
(3.8ºC) and
Below
3. Use SUPERHEAT to correctly charge unit or to
4. Set thermostat to call for heat (must have a cooling
5. Connect gauge set.
6. When heat demand is satisfied, set thermostat to
7. Allow temperatures and pressures to stabilize.
8. Measure the suction line pressure and use the use
9. Record suction line temperature:
10. Subtract to determine superheat (SHº):
11. Record the wet bulb temperature (air entering
12. Record outdoor ambient temperature.
13. Compare results with table to the left.
NOTE - Do not attempt to charge system where a
dash appears, system could be overcharged.
Superheat is taken at suction line service port.
Suction line superheat must never be less than 5ºF
at the suction line service port.
If value is MORE
than shown, then
ADD refrigerant.
°F
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
Page 32
pressures provided on applicable charging
sticker as reference in table 4.
verify the charge is correct.
load between 70‐80ºF (21-26ºC)
call for cooling.
value to determine saturation temperature (table
3):
SATº =_________
VAPº =_________
VAPº - _____ SATº ______ = SHº______
indoor coil):
WB =_______
If refrigerant is
ADDED, retest to
confirm that unit is
properly charged.
°C
15.6
18.3
21.1
23.9
26.7
29.4
32.2
35.0
37.8
40.6
43.3
46.1
48.9
51.7
54.4
57.2
60.0
62.8
65.6
Psig
170
185
201
217
235
254
274
295
317
340
365
391
418
446
476
507
539
573
608