Testing For Leaks - Lennox Dave Signature Collection XC15 Installation Instructions Manual

6. Attach the suction line sensing bulb in the proper
orientation as illustrated in figure 28 using the clamp
and screws provided.
NOTE − Insulating the sensing bulb once installed may be
required when the bulb location is external to the coil
casing.
SUCTION LINE
12
BULB
SUCTION LINE
12
BULB
BULB
Figure 28. TXV Sensing Bulb Installation
7. Remove and discard either the flare seal cap or flare
nut with copper flare seal bonnet from the equalizer
line port on the suction line as illustrated in figure 29.
IMPORTANT
When removing the flare nut, ensure that the copper
flare seal bonnet is removed.
FLARE SEAL
CAP
Figure 29. 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 25.

Testing for Leaks

After the line set has been connected to both the indoor
and outdoor units, check the line set connections and
indoor unit for leaks. Use the following procedure to test for
leaks:
506044−01 06/08
ON LINES SMALLER THAN
7/8", MOUNT SENSING BULB
AT EITHER THE 3 OR 9
O'CLOCK POSITION.
BULB
ON 7/8" AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O'CLOCK
POSITION. NEVER MOUNT
ON BOTTOM OF LINE.
NOTE − NEVER MOUNT ON BOTTOM OF
LINE.
FLARE NUT
COPPER
OR FLARE SEAL
BONNET
MALE BRASS EQUALIZER
LINE FITTING
SUCTION LINE
Leak detector must be capable of sensing HFC
refrigerant.
Refrigerant can be harmful if it is inhaled.
Refrigerant must
responsibly.
Failure to follow this warning may result in personal
injury or death.
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 HFC−410A manifold gauge set high
pressure hose to the suction valve service port.
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 HFC−410A refrigerant to the center port of the
manifold gauge set. Open the valve on the HFC−410A
cylinder (suction only).
3. Open the high pressure side of the manifold to allow
HFC−410A into the line set and indoor unit. Weigh in
a trace amount of HFC−410A. [A trace amount is a
maximum of two ounces (57 g) refrigerant or three
pounds (31 kPa) pressure]. Close the valve on the
HFC−410A cylinder and the valve on the high pressure
side of the manifold gauge set. Disconnect the
HFC−410A 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 HFC−410A mixture.
9. Correct any leaks and recheck.
Page 14
IMPORTANT
WARNING
be used and
WARNING
recovered
detector.