Page 16
IV−CHARGING
Units are factory charged with the amount of R−410A refrig-
erant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15 ft.
(4.6m) line set. For varying lengths of line set, refer to table
8 for refrigerant charge adjustment.
TABLE 8
Liquid Line Set
Diameter
Ozs. per 5 ft. (grams per 1.5m) adjust
from 15 ft. (4.6m) line set*
3/8 in.
(10mm)
3 ounces per 5 feet
(85g per 1.5m)
*If line length is greater than 15 ft. (4.6m), add this amount.
If line length is less than 15 ft. (4.6), subtract this amount.
A−Leak Testing
After the line set has been connected to the indoor and out-
door units, the line set connections and indoor unit must be
checked for leaks.
WARNING
Refrigerant can be harmful if inhaled. Refrigerant
must be used and recovered responsibly. Failure
to follow this warning can lead to injury or death.
WARNING
Fire, Explosion and Personal Safety Hazard.
Failure to follow this warning could result in damage,
personal injury or death.
Never use oxygen to pressurize or purge refrigera-
tion lines. Oxygen when exposed to a spark or open
flame can cause damage by fire and or an explosion,
that could result in personal injury or death.
WARNING
Danger of explosion: Can cause equipment damage,
injury or death. When using a high pressure gas
such as dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9 to 13.8
kPa).
Using an Electronic Leak Detector
1 − Connect a cylinder of R−410A to the center port of the
manifold gauge set.
2 − With both manifold valves closed, open the valve on
the R−410A cylinder (vapor only).
3 − Open the high pressure side of the manifold to allow
the R−410A into the line set and indoor unit. Weigh in a
trace amount of R−410A .
[A trace amount is a maxi-
mum of 2 ounces (57 g) or 3 pounds (31 kPa) pres-
sure.]
Close the valve on the R−410A cylinder and the
valve on the high pressure side of the manifold gauge
set. Disconnect the R−410A cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
5 − Connect the manifold gauge set high pressure hose to
the vapor valve service port.
(Normally, the high pres-
sure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the man-
ifold gauge set from high pressure damage.)
6 − Adjust the nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge
set which will pressurize line set and indoor unit.
7 − After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge nitrogen and R−410A
mixture. Correct any leaks and recheck.
IMPORTANT
Leak detector must be capable of sensing HFC re-
frigerant.
B−Evacuating
Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper pip-
ing and compressor parts.
IMPORTANT
Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
that reads from 50 microns to at least 23,000 microns.
1 − Connect the manifold gauge set to the service valve
ports as follows:
low pressure gauge to
vapor
line service valve
high pressure gauge to
liquid
line service valve
2 − Connect micron gauge.
3 − Connect the vacuum pump (with vacuum gauge) to the
center port of the manifold gauge set.
4 − Open both manifold valves and start vacuum pump.
5 − Evacuate the line set and indoor unit to an
absolute
pressure
of 23,000 microns (29.01 inches of mercu-
ry). During the early stages of evacuation, it is desir-
able to close the manifold gauge valve at least once to
determine if there is a rapid rise in
absolute pressure
.
A rapid rise in pressure indicates a relatively large leak.
If this occurs, repeat the leak testing procedure.
NOTE − The term absolute pressure means the total
actual pressure within a given volume or system,
above the absolute zero of pressure. Absolute pres-
sure in a vacuum is equal to atmospheric pressure mi-
nus vacuum pressure.
6 − When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
