Testing For Leaks; Evacuating The System - Lennox AC13 -018 Installation Instructions Manual

FLARE SEAL
CAP
Figure 28. Copper Flare Seal Bonnet Removal
8. Connect the equalizer line from the TXV to the
equalizer suction port on the suction line. Finger
tighten the flare nut plus 1/8 turn (7 ft−lbs) as illustrated
in figure 22.

Testing for Leaks

After the line set has been connected to the indoor unit and
air conditioner, check the line set connections and indoor
unit for leaks. Use the following procedure to test for leaks:
IMPORTANT
Leak detector must be capable of sensing HFC
refrigerant.
WARNING
Refrigerant can be harmful if it is inhaled.
Refrigerant must
responsibly.
Failure to follow this warning may result in personal
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 refrigeration 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.
1. Connect an HCFC−22 manifold gauge set high
pressure hose to the suction valve service port.
(Normally, the high pressure hose is connected to the
liquid line port; however, connecting it to the suction
port better protects the manifold gauge set from high
pressure damage.)
506109−01 10/08
FLARE NUT
COPPER
OR FLARE SEAL
BONNET
MALE BRASS EQUALIZER
LINE FITTING
SUCTION LINE
be used and recovered
NOTE − Normally, the high pressure hose is connected to
the liquid line port; however, connecting it to the suction
port better protects the manifold gauge set from high
pressure damage.
2. With both manifold valves closed, connect the cylinder
of HCFC−22 refrigerant to the center port of the
manifold gauge set. Open the valve on the HCFC−22
cylinder (suction only).
3. Open the high pressure side of the manifold to allow
HCFC−22 into the line set and indoor unit. Weigh in a
trace amount of HCFC−22. [A trace amount is a
maximum of two ounces (57 g) refrigerant or three
pounds (31 kPa) pressure]. Close the valve on the
HCFC−22 cylinder and the valve on the high pressure
side of the manifold gauge set. Disconnect the
HCFC−22 cylinder.
4. Connect a cylinder of dry nitrogen with a pressure
regulating valve to the center port of the manifold
gauge set.
5. Adjust dry nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge
set in order to pressurize the line set and the indoor unit.
6. After a few minutes, open one of the service valve
ports and verify that the refrigerant added to the
system earlier is measurable with a leak
NOTE − Amounts of refrigerant will vary with line lengths.
7. Check all joints for leaks.
8. Purge dry nitrogen and HCFC−22 mixture.
9. Correct any leaks and recheck.
10. After leak testing disconnect gauges from service
ports.

Evacuating the System

Danger of Equipment Damage. Avoid deep
vacuum operation. Do not use compressors to
evacuate a system. Extremely low vacuums can
cause internal arcing and compressor failure.
Damage caused by deep vacuum operation will
void warranty.
IMPORTANT
Use a thermocouple or thermistor electronic
vacuum gauge that is calibrated in microns. Use an
instrument capable of accurately measuring down
to 50 microns.
Evacuating the system of non−condensables is critical for
proper operation of the unit. Non−condensables are
defined as any gas that will not condense under
temperatures and pressures present during operation of
an air conditioning system. Non−condensables and water
suction combine with refrigerant to produce substances
that corrode copper piping and compressor parts.
1. Connect manifold gauge set to the service valve ports
as follows:
S low pressure gauge to suction line service valve
Page 14
WARNING
detector.