Liquid Line; Sealing The Unit - Lennox VOSB Series Installation Instructions Manual

Outside air ducted units
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Refrigerant lines must be connected by a qualified
technician in accordance with established procedures.
Field provided piping consists of two HVAC/R rated
copper lines connected to the indoor unit.
Final equipment connections must be brazed
connections. Compression or other types of fittings
are not permitted for final connections.
All refrigerant piping shall be free of defects, debris,
and oil.
Copper-phosphorous brazing alloys are to be used to
join all pipework connections where applicable.
Always flow/purge nitrogen to avoid oxidation while
brazing.
Always use an appropriate heat absorption compound
to protect the unit and internal sensors from conductive
heat while brazing.
Table 2. Refrigerant Piping Connections
Indoor Unit Size
(Btuh)
36,000
48,000
54,000
72,000
96,000

Liquid Line

Vapor Line
3/8"
5/8"
3/8"
7/8"
1. The seal on the unit refrigerant piping connections
should remain in place until the last possible moment.
This will prevent dust or moisture from getting into the
refrigerant piping before it is connected.
2. Prior to brazing remove rubber air grommets from
indoor unit refrigerant line ports.
3. Slowly loosen one of the rubber plugs to release the
factory nitrogen charge. Remove the rubber plug from
both liquid and gas lines.
4. Connect the liquid and gas lines to the evaporator coil.
5. Reinstall the rubber grommets into the refrigerant
piping panel.
6. Insulate both pipes individually.

Sealing the Unit

Seal the unit so that warm air is not allowed into the
cabinet. Warm air introduces moisture, which results in
condensation problems.
This is especially important when the unit is installed in an
unconditioned area.
If installed in an unconditioned space, sealant should be
applied around the electrical wires, refrigerant tubing, and
condensate lines where they enter the cabinet.
There must be an air-tight seal between the unit and the
return air plenum. Use fiberglass sealing strips, caulking,
or equivalent sealing method between the plenum and
the air handler cabinet to ensure a tight seal. Return
air must not be drawn from a room where this unit or
any gas-fueled appliance (i.e. water heater) or carbon
monoxide-producing device (i.e. wood fireplace) is
installed.
10
WARNING

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