Leak Testing - Lennox HSXA15 SERIES Installation Instructions Manual

To Open Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex−head extension to
back the stem out counterclockwise as far as pos-
sible.
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
Service Valve
(Valve Closed)
service
port
to outdoor coil
service
port cap
Schrader valve open
to line set when valve is
closed (front seated)
Service Valve
(Valve Open)
insert hex
wrench here
service
port
to outdoor coil
service port
cap
Schrader
valve
Figure 12
To Close Service Valve:
1 − Remove the stem cap with an adjustable wrench.
2 − Use a service wrench with a hex−head extension to
turn the stem clockwise to seat the valve. Tighten it
firmly.
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.

Leak Testing

After the line set has been connected to the indoor and
outdoor units, check the line set connections and indoor
unit for leaks.
stem cap
insert hex
wrench here
to indoor coil
(valve front seated)
stem cap
to indoor coil
Page 13
WARNING
Refrigerant can be harmful if it is inhaled. Refriger-
ant must be used and recovered responsibly.
Failure to follow this warning may result in personal
injury or death.
WARNING
Danger of explosion: Can cause
equipment damage, injury or death.
Never use oxygen to pressurize a re-
frigeration or air conditioning system.
Oxygen will explode on contact with
oil and could cause personal injury.
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 the high pressure hose of the manifold gauge
set to the vapor valve service port. (Normally, the high
pressure hose is connected to the liquid line port, how-
ever, connecting it to the vapor port helps to protect the
manifold gauge set from damage caused by high pres-
sure.)
2 − With both manifold valves closed, connect the cylinder
of R410A refrigerant to the center port of the manifold
gauge set. Open the valve on the R410A cylinder (va-
por only).
3 − Open the high pressure side of the manifold to allow
R410A into the line set and indoor unit. Weigh in a trace
amount of R410A. [A trace amount is a maximum of 2
ounces (57 g) refrigerant or 3 pounds (31 kPa) pres-
sure.] Close the valve on the R410A cylinder and the
valve on the high pressure side of the manifold gauge
set. Disconnect R410A cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
5 − Adjust 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 coil.
6 − After a few minutes, open a refrigerant port to check
that an adequate amount of refrigerant has been add-
ed for detection (refrigerant requirements will vary
with line lengths). Check all joints for leaks. Purge ni-
trogen and R410A mixture. Correct any leaks and re-
check.