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506645−01
START: Measure outdoor ambient temperature
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.
USE WEIGH-IN METHOD
Weigh-in or remove refrigerant
based upon line length
SHº (Superheat) Values (+/−5ºF)
Wet Bulb (air entering indoor coil)
ºF* 50 52 54 56 58 60 62 64 66 68 70 72 74 76
40 15 18 20 23 26 29 32 34 38 41 43 46 48 51
45 13 16 18 21 24 27 30 33 36 39 41 44 46 49
50 11 14 16 19 22 25 28 31 34 37 39 42 44 47
55 9 12141720232730333638404244
60 7 10121518212427303335384043
65 - 6 10 13 16 19 21 24 27 30 33 36 38 41
70 - - 7 1013161921242730333639
75 - - - 6 9 121518212428313437
80 - - - - 5 8 12 15 18 21 25 28 31 35
85 - - - - - - 8 11 15 19 22 26 30 33
90 - - - - - - 5 9 131620242731
95 - - - - - - - 6 101418222529
100 --------81216212428
105 --------5913172226
110 ---------611152025
115 ----------8141824
* Dry−bulb temperature (ºF) of entering outdoor ambient air.
1. Confirm proper airflow across coil using figure 19.
2. Compare unit pressures with table 4, Normal
Operating Pressures.
3. Use SUPERHEAT to correctly charge unit or to
verify the charge is correct.
4. Set thermostat to call for heat (must have a cooling
load between 70-80ºF (21−26ºC)
5. Connect gauge set.
6. When heat demand is satisfied, set thermostat to
call for cooling.
7. Allow temperatures and pressures to stabilize.
8. Measure the suction line pressure and use the use
value to determine saturation temperature (table
3):
SATº =_________
9. Record suction line temperature:
VAPº =_________
10. Subtract to determine superheat (SHº):
VAPº − _____ SATº ______ = SHº______
11. Record the wet bulb temperature (air entering
indoor coil):
WB =_______
12. Record outdoor ambient temperature.
13. Compare results with table to the left.
If value is MORE
than shown, then
ADD refrigerant.
If value is LESS than
shown, then REMOVE
refrigerant.
If refrigerant is
REMOVED, retest to
confirm that unit is
properly charged.
MORE or
LESS
If refrigerant is
ADDED, retest to
confirm that unit is
properly charged.
ABOVE or
BELOW
39ºF
(3.8ºC) and
Below
40ºF
(4.4ºC) and
Above
SUPERHEAT RFC
Figure 24. HFC−410A Superheat RFC Method
Table 3. HFC−410A Temperature Ċ Pressure (Psig)
°F °C Psig °F °C Psig
−40 −40.0 11.6 60 15.6 170
−35 −37.2 14.9 65 18.3 185
−30 −34.4 18.5 70 21.1 201
−25 −31.7 22.5 75 23.9 217
−20 −28.9 26.9 80 26.7 235
−15 −26.1 31.7 85 29.4 254
−10 −23.3 36.8 90 32.2 274
−5 −20.6 42.5 95 35.0 295
0 −17.8 48.6 100 37.8 317
5 −15.0 55.2 105 40.6 340
10 −12.2 62.3 110 43.3 365
15 −9.4 70.0 115 46.1 391
20 −6.7 78.3 120 48.9 418
25 −3.9 87.3
125 51.7 446
30 −1.1 96.8 130 54.4 476
35 1.7 107 135 57.2 507
40 4.4 118 140 60.0 539
45 7.2 130
145 62.8 573
50 10.0 142
150 65.6 608
55 12.8 155