Johnson Controls YVAHP0721CW Series, Service Manual

Page: 41 / 416

SM-16007
1-27
INSTALLATION
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Cautions for Refrigerant Pipe Ends
6.1 Piping Materials
(1) Obtain locally-supplied copper pipes.
(2) Use the copper pipe for refrigerant piping.
(3) Pay close attention to pipe thickness.
(4) Use clean copper pipes. Make sure there is no dust or moisture inside the pipes. Blow nitrogen or dry
compressed air into the pipes to remove any dust or foreign materials before connecting them.
Do not use any tools which produce a lot of swarf such as a saw or grinder.
(5) Take special care to prevent contamination or moisture settling on interior pipe surfaces during piping
work.
(6) Avoid performing the piping connection work for outdoor units in the rain.
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Brazing Work
(1) Brazing work must be performed by an authorized installer in order to prevent any problems.
(2) For piping connections, complete non-oxidation brazing with a nitrogen charge. If brazing the pipes
without the nitrogen substitution, a large amount of oxidized scaling will be generated in the piping.
This oxidized scaling can cause clogging inside the expansion valve, solenoid valve, accumulator, and
compressor, which can prevent the unit from operating properly.
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NOTICE:
To avoid oxidation and scaling, perform brazing at the appropriate temperature.
NOTES:
1. Make sure to use nitrogen. Nitrogen gas pressure shall be 2.9 psi (0.02 MPa) or less.
DO NOT use the following gases.
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Carbon Dioxide: This can cause decreased performance over drier periods.
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2. Make sure to use the pressure-reducing valve.
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When installing pipe through
the wall, secure a cap at the
end of the pipe.
Correct
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Hole Hole
Attach a cap
or vinyl tape.
Attach a cap
or vinyl tape.
Attach a cap
or vinyl bag with
rubber band.
Do not place the pipe
directly on the ground.
Rain water
can enter.
Nitrogen
Gas
Pressure Reducing Valve
(Stop Valve)
Nitrogen Gas Pressure
< 2.9 psi (0.02 MPa)
Brazing Part
NOTE:
Do not cover the outlet. If the inner
pressure exceeds atmospheric pressure,
a pinhole will result and refrigerant gas
will leak from the brazed fitting.
Cover the gap with
tape or a rubber plug
to prevent air from entering
the pipe interior.
Valve Pipe
(1/4 inch)
Nitrogen Gas
Piping Connection on-site