Refrigerant Piping Connections - Lennox MPA024S4S-*P Installation Instructions Manual

Refrigerant Piping Connections

Field piping consists of two copper lines connecting the
outdoor unit to the indoor unit. "Table 2. Refrigerant Piping
and Indoor Unit Connection Sizes" lists the connection
sizes. The connections are made using the provided brass
flare nuts at the end of the refrigerant piping connections.
Both lines must be individually insulated.
1. The seal on the unit refrigerant piping connections
should remain in place until the last possible moment.
This will prevent dust or water from getting into the
refrigerant piping before it is connected.
2. CAREFULLY adjust refrigerant piping connections to
suit the application.
3. Slowly loosen one of the flare nuts to release the
factory nitrogen charge from the indoor units only.
4. Remove the flare nuts from the connections on the
unit and discard the seal from each of the piping
connections.
5. Slide the flare nuts onto the ends of the field-provided
refrigerant piping before using a suitable flaring tool to
flare the end of the copper pipe.
6. Apply recommended HFC-410A refrigerant lubricant
to the outside of the flared refrigerant lines.
IMPORTANT
The compressor in
oil (Polyvinylether).
hydro-fluorocarbon (HFC) refrigerants, such as HFC-
410A, which this system contains. While it may have
some miscibility properties with mineral-based oil and
POE oil (Polyolester), it is not recommended to mix PVE
oil with any other type of refrigerant oil.
7. Align the threaded
flared refrigerant lines. Tighten the flare nuts
lightly at first to obtain a smooth match as
illustrated in "Figure
(Male to Female Connection)".
8. Once snug, continue another half-turn on each nut
which should create a leak-free joint. A torque wrench
may be used to tighten flare nuts using "Table 3. Flare
Nut Torque Recommendations". Do not over-tighten
a flared joint. Flared connections should always
be accessible and must be insulated to prevent
condensation.
9. After refrigerant piping has been installed and checked
for leaks, apply insulation over all flared connections.
Table 2. Refrigerant Piping and Indoor Unit
Connection Sizes
Size Liquid Line
(Btuh)
18000
24000, 36000 &
48000
this unit contains
PVE oil is formulated
connections with
25. Making Connections
Gas Line
in. in.
1/4 1/2
3/8 5/8
A
B
Figure 25. Making Connections
TO INDOOR
UNIT
Table 3. Flare Nut Torque Recommendations
PVE
for
Outside
Diameter
Inches
1/4
3/8
1/2
the
5/8
13
CANT ON THE OUTSIDE OF
(Male to Female Connection)
TORQUE WRENCH
TO OUTDOOR UNIT
Figure 26. Tighten Flare Nut
No torque wrench available
Recommended
Finger tighten and use an
Torque
appropriately sized wrench to
turn an additional:
15 ft.-lb. (20 N)
26 ft.-lb. (35 N)
41 ft.-lb. (56 N)
48 ft.-lb. (65 N)
THE FLARE
MALE FLARE
CONNECTION
BACKUP
WRENCH
1/4 turn
1/2 turn
7/8 turn
1 full turn