Brazing Refrigerant Lines; Sealing The Unit - Lennox VRF VVCA Series Installation Instructions Manual

Brazing Refrigerant Lines

Refrigerant lines must be connected by a qualified
technician in accordance with established procedures.
WARNING
Danger of fire. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing torch
to a pressurized system may result in ignition
of the refrigerant and oil mixture. Check the
high and low pressures before applying heat.
CAUTION
Brazing alloys and flux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing operations.
Perform operations only in well-ventilated areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and flux.
CAUTION
Purge low pressure nitrogen [1 to 2 psig (6.0 to 12.8
kPA)] through the refrigerant piping during brazing. This
will help to prevent oxidation and the introduction of
moisture into a system.
To prevent the build-up of high levels of nitrogen when
purging be sure it is done in a well ventilated area.
IMPORTANT
Refrigerant lines must be clean, dry, refrigerant-grade
copper lines. Air handler coils should be installed
only with specified line sizes for approved system
combinations.
Handle refrigerant lines gently during the installation
process. Sharp bends or kinks in teh lines will cause
restrictions.
IMPORTANT
Only use brazing rods/sticks which are suitable/
recommended for air conditioning pipework installations
- Do Not Use Soft Solder.
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. To avoid damaging the rubber grommets in the
cabinet while brazing, slide the rubber grommets over
the refrigerant lines until they are away from the heat
source.
3. Remove rubber plug from both liquid and gas lines or
cut pipework tails to suit field installation conditions
4. Connect the liquid and gas lines to the evaporator coil.
5. Place a wet rag against piping plate and around the
line connections. Take care to protect the cabinet
and internal components.
6. Ensure nitrogen is flowing at all times during the
brazing process.
7. Braze connections. Allow pipe to cool before removing
wet rag.
8. Reinstall the rubber grommets into the refrigerant
piping panel.
9. 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
water blow-off 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 bottom of
the air handler 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 air handler or any gas-fueled appliance
(i.e. water heater) or carbon monoxide-producing device
(i.e. wood fireplace) is installed.
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WARNING