Lennox Elite XC13 Installation Instructions Manual page 24

START: Measure outdoor ambient temperature
USE WEIGH-IN METHOD
DO NOT CHARGE UNIT
Weigh-in or remove refrigerant
(Results of charging at low
based upon line length
temperatures not reliable)
SUBCOOLING TXV
C
BLOCK OUTDOOR COIL: [sometimes necessary with lower
temperatures] Use cardboard or plastic sheet to restrict the airflow
through the outdoor coil to achieve pressures from 325−375 psig
(2240−2585 kPa). Higher pressures are needed to check charge. Block
equal sections of air intake panels and move coverings sideways until
the liquid pressure is in the above noted ranges.
Once refrigerant charge is
correct, disconnect gauge set
and replace service port caps.
If refrigerant is added or
removed, verify charge
using the Approach
Method.
If value is LESS
than shown, add
refrigerant.
START: Measure outdoor ambient temperature
USE SUPERHEAT
WEIGH IN FIXED ORIFICE
D
Once refrigerant charge is
correct, disconnect gauge set
and replace service port caps.
Refrigerant Charge per Line Set Length
Liquid Line
Set Diameter
3/8" (9.5 mm)
Figure 38. Using HFC−410A Weigh In (Fixed Orifice) Charge Method
506120−01 03/10
ABOVE or
BELOW
64ºF and
BELOW
CARDBOARD OR
PLASTIC SHEETS
If value is MORE
than shown, remove
refrigerant.
MORE or
LESS
Figure 37. Using HFC−410A Subcooling (TXV) Charge Method
40ºF
and
ABOVE
Ounces per 5 feet (g per 1.5 m)
adjust from 15 feet (4.6 m) line set*
3 ounce per 5' (85 g per 1.5 m)
1. Connect gauge set as illustrated in figure 32.
65ºF
2. Confirm proper airflow across coil using figure 33.
and
3. Compare unit pressures with table 4, Normal
ABOVE
4. Set thermostat to call for heat (must have a cooling
5. Measure outdoor ambient temperature
6. When heat demand is satisfied, set thermostat to call
7. Allow temperatures and pressures to stabilize.
8. Record liquid line temperature:
9. Measure liquid line pressure and use the value to
10. Subtract to determine subcooling (SCº):
11. Compare results with table below.
SCº (Subcooling) Values (F:+/−1.0° [C: +/−0.6°])
ºF (ºC)* −018 −024
Any 10 (5.6) 10 (5.6)
*Temperature of air entering outdoor coil
39ºF and
BELOW
ABOVE or
BELOW
Page 24
Operating Pressures.
load between 70-80ºF (21−26ºC)
for cooling
NOTE − If necessary, block outdoor coil to maintain
325 − 375 psig.
LIQº = ______
determine saturation temperature (see table 3):
SATº = ______
SATº_____ − LIQº _____ = SCº _____
−030 −036 −042
9 (5.0) 12 (6.7) 8 (4.4)
1. Connect gauge set as illustrated in figure
32.
2. Check Liquid and suction line pressures
3. Compare unit pressures with table 4,
Normal Operating Pressures.
4. Weigh in the unit nameplate charge plus
any charge required for line set differences
over feet.
This nameplate
illustration purposes only.
Go to actual nameplate on
outdoor unit for charge
information.
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.
−048 −060
9 (5.0) 7 (3.9)
is for