Lennox 14HPX Unit Information page 19

D − Charge using Weigh−in Method
Weigh−in:
1. Recover the refrigerant from the unit.
2. Conduct leak check; evacuate as previously outlined.
3. Weigh in the unit nameplate charge plus any charge
required for lineset differences from 15 feet and any
extra indoor unit matchup amount per table 7. (If
weighing facilities are not available, use the subcooling
method.)
TABLE 6
Liquid Line Oz. per 5 ft. (g per 1.5m) adjust from
Set Diameter 15 ft. (4.6m) line set*
3/8 in. (9.5mm) 3 ounce per 5 ft. (85g per 1.5m)
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.
Adding Charge per Indoor Unit Matchup using Subcooling Method
Use
cooling
mode
60ºF (15ºC)
Use
heating
mode
SATº
LIQº –
SCº =
Subcool Target
INDOOR HEAT
Heating Cooling
MATCHUP PUMP
(+5ºF) (+1ºF)
14HPX−018
CBX27UH−018/024 13
CBX32MV−018/024 15
14HPX−024
CH23−41 16
CBX26UH−024 25
CBX27UH−018/024 15
CBX32M−018/024 16
CBX32M−030 15
CBX32MV−018/024 16
CBX32MV−024/030 15
CH33−42B 14
CH33−36A 16
CH33−36C 16
CR33−30/36A/B/C 25
1. Check the airflow (figure 18) to be sure the indoor airflow is as required. (Make any air
flow adjustments before continuing with the following procedure.)
2. Measure outdoor ambient temperature; determine whether to use cooling mode or
heating mode to check charge.
3. Connect gauge set.
4. Check Liquid and Vapor line pressures. Compare pressures with Normal Operating
Pressures table 5, (Table 5 is a general guide. Expect minor pressures variations.
Significant differences may mean improper charge or other system problem.)
5. Set thermostat for heat/cool demand, depending on mode being used:
When the outdoor ambient temperature is 60°F (15°C) and above.
Using cooling mode
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 68ºF (20ºC). When pressures have stabilized,
continue with step 6..
When the outdoor ambient temperature is below 60°F (15°C).
Using heating mode
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 77ºF (25ºC). When pressures have stabilized,
continue with step 6..
6. Read the liquid line temperature; record in the LIQº space.
7. Read the liquid line pressure; then find its corresponding temperature in the temperature/
pressure chart (table 8) and record it in the SATº space.
8. Subtract LIQº temp. from SATº temp. to determine subcooling; record it in SCº space.
9. Compare SCº results with table below, being sure to note any additional charge for lineset
and/or matchup.
10. If subcooling value is greater than shown in table, remove refrigerant; if less than
shown, add refrigerant.
11.If refrigerant is added or removed, repeat steps 5. through 10. to verify charge.
*Add INDOOR
charge MATCHUP
lb oz 14HPX−030 (cont'd)
7 0 8 CX34−31A/B
7 0 0 CX34−38A/B
lb oz
CX34−43B/C
14HPX−036
8 0 2
7 0 0 CBX26UH−036
8 1 2 CBX26UH−037
8 0 14 CBX27UH−036
8 1 3 CBX32M−036
8 0 14 CBX32M−042
8 1 2 CBX32MV−036
11 1 10 CBX32MV−048
8 1 0 C33−44C
8 0 4 CH33−50/60C
7 0 2 CH33−44B
E − Charge using Subcooling Method
Requirements these items are required for charging:
S
Manifold gauge set connected to unit.
S
Thermometers for measuring outdoor ambient, liquid
line, and vapor line temperatures.
When to use cooling mode When outdoor temperature
is 60°F (15°C) and above, use cooling mode to adjust
charge.
When to use heating mode When the outdoor tempera-
ture is below 60°F (15°C), use the heating mode to adjust
the charge.
Adding Charge for Indoor Matchups Table 7 lists all
the Lennox recommended indoor unit matchups along with
the charge levels for the various sizes of outdoor units.
TABLE 7
Subcool Target
HEAT *Add
Heating Cooling
PUMP charge
(+5ºF) (+1ºF)
lb oz
11 6 1 6
11 6 2 3
15 11 2 14
lb oz
26 5 0 0
25 4 1 9
13 6 0 3
13 6 0 2
13 6 0 3
13 6 0 3
11 8 2 5
13 6 0 0
11 8 2 5
13 6 1 7
Page 19
Subcool Target
INDOOR HEAT
Heating Cooling
MATCHUP PUMP
(+5ºF) (+1ºF)
14HPX−042 (cont'd)
CX34−62C, −62D 12
CX34−49C 12
CX34−60D 12
14HPX−048
CH23−68 20
CBX26UH−048 8
CBX27UH−048 11
CBX32M−048, −060 11
CBX32MV−048, −060 11
CBX32MV−068 10
CH33−50/60C 11
CH33−62D 10
CH33−60D 11
CR33−50/60C 35
*Add
charge
lb oz
6 0 9
6 0 7
6 0 4
lb oz
9 2 9
7 1 9
8 1 2
8 1 2
8 1 2
7 1 12
8 1 1
7 1 14
8 0 0
5 0 0