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TDOOR TEMPERATURE ˚F

0           7 5         8 0           8 5         9 0           9 5       1 0 0       1 0 5       1 1 0       1 1 5

EXAMPLE:  SUCTION PRESSURE=65#. SUCTION TEMP=70˚F 
WHICH GIVES AN ACTUAL SUPERHEAT OF 32˚F.
OD TEMP=90˚F

 ID TEMP=80˚F

 

INTERSECTION OF ID AND OD TEMPS

 OCCUR ON THE 

12˚F SUPERHEAT LINE

ADD CHARGE TO OBTAIN 12˚ SUPERHEAT.

ED ON 400 CFM/TON INDOOR AIRFLOW AND 

MIDITY, USE ON SYSTEMS THAT COOL WITH  FCCV 

RHEAT CHARGING CHART

LIMIT LINE

tion temperature at OD quick attach, ID & OD temps. Determine from

 for the ID & OD temp. Example indicates 12˚ superheat. Determine

zed running conditions.

s OK

 

more than 5˚ below chart value remove refrigerant

e add refrigerant

 

if below 5˚ limit line, do not add refrigerant

F

rom Dwg.

 21C141108 Re

v.

 0

1

3

Dwg. No. 4TWR2036-SF-1     Page E-757-000

WIRING DIAGRAM

A150999P05 REV. 0

LOWER CURVE

MIDDLE CURVE

UPPER CURVE

20

10

30

25

40

80

60

60
50
40
30
25
20
15
10

0

REFRIGERANT

LINE  LIFT

(FEET)

TOTAL REFRIGERANT LINE LENGTH (FEET)

CHARGING CURVE SELECTION CHART

TXV REFRIGERANT CHARGING CURVE

For charging  outdoor units with R-410A refrigerant at above 65˚F 

outdoor temperature in cooling mode and with indoor TXV. 

LIQUID PRESSURE (PSIG.)

130

120

110

100

90

80

70

600

550

500

450

400

350

300

250

200

LIQUID TEMPERATURE (˚F.)

ADD REFRIGERANT

REMOVE REFRIGERANT

1.

2.

3.

4.

5.

6.

Measure Liquid Line Temperature and
Refrigerant Pressure at service valves.

Determine total refrigerant pipe length
and height (lift) if indoor section is above
the condenser. Plot the intersection of
the two points on the Curve Selection
Chart to determine which curve to use.

Plot the pressure and temperature on 
the TXV Charging Curve.

If the lines cross above the curve remove
refrigerant, if below curve add refrigerant.

Whenever charge is removed 
or added, the system must 
be operated for a minimum
20 minutes to stabilize before 
additional measurements can 
be made.

When system is correctly 
charged refer to System 
Performance Curves to verify
charge and performance.

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