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3.9 PRECAUTIONS DURING BRAZING OF LINES
All outdoor unit and evaporator coil connections are copper-to-copper and should be
brazed with a phosphorous-copper alloy material such as Silfos-5 or equivalent. DO
NOT use soft solder. The outdoor units have reusable service valves on both the liquid
and suction connections. The total system refrigerant charge is retained within the
outdoor unit during shipping and installation. The reusable service valves are provided
to evacuate and charge per this instruction.
Serious service problems can be avoided by taking adequate precautions to assure an
internally clean and dry system.
Dry nitrogen should always be supplied through the tubing while it is being
brazed, because the temperature required is high enough to cause oxidation
of the copper unless an inert atmosphere is provide. The flow of dry nitrogen
should continue until the joint has cooled. Always use a pressure regulator
and safety valve to insure that only low pressure dry nitrogen is introduced into
the tubing.Only a small flow is necessary to displace air and prevent oxidation.
3.10 PRECAUTIONS DURING BRAZING SERVICE VALVE
Precautions should be taken to prevent heat damage to service valve by wrapping a wet
rag around it as shown in Fig.10. Also, protect all painted surfaces, insulation, during
brazing. After brazing cool joint with wet rag.
The valve can be opened by removing the plunger cap and fully inserting a hex wrench
into the stem and backing out counter-clockwise until valve stem just touches the cham-
fered retaining wall.
Connect the refrigerant lines using the following procedure:
1. Remove the cap and Schrader core from both the liquid and suction service valve
service ports at the outdoor unit. Connect Iow pressure nitrogen to the liquid line
service port.
service valve
wet rag
2. Braze the liquid line to the liquid valve at the outdoor unit. Be sure to wrap the valve
body with a wet rag. Allow the nitrogen to continue flowing. Refer to the Tabular Data
Sheet for proper liquid line sizing.
3. Carefully remove the rubber plugs from the evaporator liquid and suction connections
at the indoor coil.
CAUTION
Fig.10 Heat Protection
11
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