Lennox XC14 Installation Instructions Manual page 21

START: Measure outdoor ambient temperature
USE SUPERHEAT
WEIGH IN RFC
Refrigerant Charge per Line Set Length
Liquid Line Ounces per 5 feet (g per 1.5 m)
Set Diameter adjust from 15 feet (4.6 m) line set*
3/8" (9.5 mm)
3 ounce per 5' (85 g per 1.5 m)
NOTE − *If line length is greater than 15 ft. (4.6 m), add this
amount. If line length is less than 15 ft. (4.6 m), subtract this
amount.
START: Measure outdoor ambient temperature
USE WEIGH-IN METHOD
Weigh-in or remove refrigerant
based upon line length
ºF*
40
45
50
55
60
65
70
75
80
85
90
95
100
105
If refrigerant is 110
added, retest to
115
confirm that unit is
* Dry−bulb temperature (ºF) of entering outdoor ambient air.
properly charged.
If value is LESS than
shown,
refrigerant.
ABOVE or
40ºF
and
ABOVE
Figure 38. Using HFC−410A Weigh In RFC Charge Method
ABOVE or
BELOW
39ºF and
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
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
add MORE or
LESS
Figure 39. Using HFC−410A Superheat RFC Charge Method
39ºF and
BELOW
BELOW
40ºF
and
ABOVE
10. Subtract to determine superheat (SHº):
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
- 6 11 15 20 25
- - 8 14 18 24
If value is MORE
than shown, remove
refrigerant.
Page 21
1. Check Liquid and suction line pressures
2. Compare unit pressures with table 7,
Normal Operating Pressures.
3. Conduct leak check;
previously outlined.
4. Weigh in the unit nameplate charge plus
any charge required for line set differences
over feet.
This nameplate is for illustration purposes
only. Go to actual nameplate on outdoor unit
for charge information.
1. Confirm proper airflow across coil using figure 33.
2. Compare unit pressures with table 7, 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
6):
SATº =_________
9. Record suction line temperature:
VAPº =_________
VAPº − _____ SATº ______ = SHº______
11. Record the wet bulb temperature (air entering
indoor coil):
WB =_______
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 refrigerant is
removed, retest to
confirm that unit is
properly charged.
evacuate as
XC14 SERIES