SYSTEM CHARGE
The factory charge in the outdoor unit is listed in Table 2 and
includes enough charge for the unit and a most sold matched
evaporator. Some indoor coil matches may require some ad-
ditional charge.
Sweat connect units also include sufficient charge for 15 feet
of lines. Pre-charged line lengths are factory charged with the
correct amount of refrigerant required. Table 3 lists the refrig-
erant line charges.
The “TOTAL SYSTEM CHARGE” must be permanently
stamped on the unit data plate.
Total system charge is determined as follows:
1. Determine the outdoor unit charge from Table 2.
2. Determine indoor coil adjustment from Table 2.
3. Calculate the line charge using Table 3 factors. Calculate
over 15 feet of sweat lines for sweat connect units.
NOTE: For sweat connect lines, the line charge over 15 feet
should be included on the data plate and must be
added to the system.
4. Total system charge = item 1 + item 2 + item 3.
5. Permanently stamp the unit data plate with the total amount
of refrigerant in the system.
Use one of the following charging methods whenever addi-
tional refrigerant is required for the system charge.
CAUTION: Refrigerant charging should only be carried out by
a qualified air conditioning contractor.
Measurement Method
If a calibrated charging cylinder or accurate weighing device is
available, add refrigerant accordingly.
CAUTION: Compressor damage will occur if system is improp-
erly charged. On new system installations charge
system per R-22 charge information label and fol-
low guidelines in this instruction.
Check flare caps on service ports to be sure they are leak tight.
DO NOT OVER TIGHTEN (between 40 and 60 inch - lbs.
maximum).
Superheat Charging Method
NOTE: Use this method only during system maintenace and
repair.
1. Operate system until temperatures and pressures stabilize
(minimum of 10 minutes).
2. Measure and record indoor wet bulb (WB) temperature
using a sling psychrometer and the outdoor dry bulb (DB)
temperature using a thermometer.
3. Measure and record the suction pressure at the suction
service valve port.
4. Using Table 4, note the superheat value corresponding to
the intersection of the indoor wet bulb and the outdoor dry
bulb.
5. With the superheat value obtained in step 4 and the suction
pressure value from step 3, find the intersection of the
values in Table 5. This is the required suction tube tempera-
ture at the suction service valve.
6. To bring the tube temperature in line with the required value
from Table 5, add refrigerant to the service port to cause
the tube temperature to fall and reclaim refrigerant to cause
the temperature to rise.
UNIT
SIZE
LIQUID
LINE OD
VAPOR
LINE OD
R. CHARGE
ADDER (OZ / FT)
024 TO 036
3/8
3/4
0.68
042 TO 060
3/8
7/8
0.70
TABLE 3 - REFRIGERANT LINE CHARGES
550.36-N2Y
Unitary Products Group
7
