Lennox 14HPX-018 Installation Instructions Manual page 14

WEIGH
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*
3t8"
(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.
LENNOX
DALLAS, EXAS
M/N TSAO31N_4N41G
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1. Check Liquid and suction line pressures
2. Compare unit pressures with table 12,
Normal Operating Pressures.
3. Conduct leak check; evacuate as
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.
Figure 17. Using Weigh In Method
SUBCOOUNG 1
!i !i!ili!i!i iB ii iii '
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iX_ N _
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USE COOLING
MODE
-- 60OF {15 °) --
USE HEATING
MODE
2
3
4
SAT o
LIQ o -
SC o =
Check the airflow as illustrated in figure 15 to be sure the indoor airflow is as
required. (Make any air flow adjustments before continuing with the following
procedure,)
Measure outdoor ambient temperature; determine whether to use cooling mode
or heating mode to check charge,
Connect gauge set,
Check Liquid and Vapor line pressures, Compare pressures with Normal
Operating Pressures table 11, (The reference table is a general guide. Expect
minor pressure variations. Significant differences may mean improper charge or
other system problem.)
Set thermostat for heat/cool demand, depending on mode being used:
Using cooling mode--When the outdoor ambient temperature is 60°F (15°C) and
above. Target subcooling values in table below are based on 70 to 80°F (21-27°C)
indoor return air temperature; if necessary, operate heating to reach that
temperature range; then set thermostat to cooling mode setpoint to 68°F (20°C).
When pressures have stabilized, continue with step 6,
Using heating mode--When the outdoor ambient temperature is below 60°F (15°C).
Target subcooling values in table below are based on 65-75°F (18-24°C) indoor
return air temperature; if necessary, operate cooling to reach that temperature range;
then set thermostat to heating mode setpoint to 77°F (25°C), When pressures have
stabilized, continue with step 6.
6 Read the liquid line temperature; record in the LIQ° space.
7 Read the liquid line pressure; then find its corresponding temperature in the
temperature/pressure chart listed in table 12 and record it in the SAT° space,
8 Subtract LIQ° temp. from SAT° temp. to determine subcooling; record it in SC° space.
9 Compare SC° results with table below, being sure to note any additional charge for
line set and/or match-up,
10 If subcooling value is greater than shown in tables 4 through 10 for the applicable unit,
remove refrigerant; if less than shown, add refrigerant.
11 If refrigerant is added or removed, repeat steps 6 through 10 to verify charge.
Figure 18. Using Subcooling Method
505243 04/08
Page 14