Lennox Merit Series13ACD Installation Instructions Manual page 17

START: Measure outdoor ambient temperature
USE WEIGH-IN METHOD
Weigh-in or remove refrigerant
based upon line length
ºF*
40
45
50
55
60
If refrigerant added or
65
removed, retest to confirm
70
that unit is properly
75
charged
80
85
90
95
If value is greater than
100
shown, add refrigerant; if
105
less than shown, remove
refrigerant.
110
115
* Dry−bulb temperature (ºF) of entering outdoor ambient air.
Outdoor
Ambient 40ºF
(4ºC)?
BELOW
SHº (Superheat) Values (+/−5ºF)
Wet Bulb (air entering indoor coil)
50 52 54 56 58 60 62 64 66 68 70 72 74 76
15 18 20 23 26 29 32 34 38 41 43 46 48 51
13 16 18 21 24 27 30 33 36 39 41 44 46 49
11 14 16 19 22 25 28 31 34 37 39 42 44 47
9 12 14 17 20 23 27 30 33 36 38 40 42 44
7 10 12 15 18 21 24 27 30 33 35 38 40 43
- 6 10 13 16 19 21 24 27 30 33 36 38 41
- - 7 10 13 16 19 21 24 27 30 33 36 39
- - - 6 9 12 15 18 21 24 28 31 34 37
- - - - 5 8 12 15 18 21 25 28 31 35
- - - - - - 8 11 15 19 22 26 30 33
- - - - - - 5 9 13 16 20 24 27 31
- - - - - - - 6 10 14 18 22 25 29
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
Figure 32. HCFC−22 Superheat RFC Charge
1. Confirm proper airflow across coil using figure 27.
2. Compare unit pressures with Table 6, Normal
ABOVE
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.
8 12 16 21 24 28
5 9 13 17 22 26
NOTE − Do not attempt to charge system where a
- 6 11 15 20 25
dash appears, system could be overcharged.
- - 8 14 18 24
Superheat is taken at suction line service port.
Suction line superheat must never be less than 5ºF
at the suction line service port.
Page 17
Operating Pressures.
verify the charge is correct.
load between 70-80ºF (21−26ºC)
call for cooling.
value to determine saturation temperature:
SATº =_________
VAPº =_________
VAPº − _____ SATº ______ = SHº______
indoor coil):
WB =_______
13ACD SERIES