17
ENGLISH
29
■
Wiring sample
Torque value of power supply terminal board:
2.0 N·m ± 0.05 N·m {20
kg
f·cm ± 0.5
kg
f·cm}
Torque value of communication terminal board:
1.3 N·m ± 0.1 N·m {13
kg
f·cm ± 1
kg
f·cm}
ATTENTION:
Comply with the torque values.
If tightening over torque values, the screw will be damaged.
ATTENTION:
Apply an adjustable wrench to the valve vertically not to
damage the P.C. board.
Use this screw when connecting to
ground for the inter-unit control wiring.
Inter-unit control wiring
Power supply
Earth
■
Wiring procedure
Follow the wiring procedure below for terminal connection.
(1)
Set the wiring and cables for the power and signal lines to the outdoor unit together, and secure each wire and cable with
the tie.
(2)
Secure and clamp the power and signal lines with the tie, set up close to the valve.
(3)
Set up the wiring and cable for the outdoor unit piping and secure with a tie.
1
Secure and clamp the wiring and cable with the tie (field supply) for the power and signal lines to the outdoor unit.
2
Secure and clamp the wiring and cable together with power and signal lines using the tie set up close to the valve.
3
Secure and clamp all wiring and cable together with the indoor/outdoor piping using the tie (field supply).
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30
5.
HOW
TO
PROCESS
TUBING
The liquid tubing side is connected by a flare nut, and the gas
tubing side is connected by brazing.
5-1.
Connecting the Refrigerant Tubing
Use of the Flaring Method
Many of conventional split system air conditioners employ the
flaring method to connect refrigerant tubes which run between
indoor and outdoor units. In this method, the copper tubes are
flared at each end and connected with flare nuts.
Flaring Procedure with a Flare Tool
(1)
Cut the copper tube to the required length with a tube
cutter. It is recommended to cut approx. 30 – 50 cm longer
than the tubing length you estimate.
(2)
Remove burrs at the end of the copper tube with a tube
reamer or a similar tool. This process is important and
should be done carefully to make a good flare.
Be sure to keep any contaminants (moisture, dirt, metal
filings, etc.) from entering the tubing.
NOTE
When reaming, hold the tube end downward and be sure that
no copper scraps fall into the tube.
(3)
Remove the flare nut from the unit and be sure to mount it
on the copper tube.
(4)
Make a flare at the end of copper tube with a flare tool.
Flare nut
Flare tool
Copper tubing
NOTE
A good flare should have the following characteristics:
●
Inside surface is glossy and smooth
●
Edge is smooth
●
Tapered sides are of uniform length
Caution Before Connecting Tubes Tightly
(1)
Apply a sealing cap or water-proof tape to prevent dust or
water from entering the tubes before they are used.
(2)
Be sure to apply refrigerant lubricant (ether oil) to the inside
of the flare nut before making piping connections. This is
effective for reducing gas leaks.
Apply refrigerant
lubricant.
(3)
For proper connection, align the union tube and flare tube
straight with each other, then screw in the flare nut lightly at
first to obtain a smooth match.
Union
Flare nut
●
Adjust the shape of the liquid tube using a tube bender at
the installation site and connect it to the liquid tubing side
valve using a flare.
Cautions During Brazing
●
Replace air inside the tube with nitrogen gas to prevent
copper oxide film from forming during the brazing
process. (Oxygen, carbon dioxide and Freon are not
acceptable.)
●
Do not allow the tubing to get too hot during brazing.
The nitrogen gas inside the tubing may overheat,
causing refrigerant system valves to become damaged.
Therefore allow the tubing to cool when brazing.
●
Use a reducing valve for the nitrogen cylinder.
●
Do not use agents intended to prevent the formation
of oxide film. These agents adversely affect the
refrigerant and refrigerant oil, and may cause damage
or malfunctions.
Pressure-reducing
valve (regulator)
Work method
Work method
Field-supply tube
Remote valve
Brazing locations
Taping
Pressure-reducing
valve (regulator)
Nitrogen
Before
after
Copper tubing
Reamer
Deburring
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00̲280434̲Mini̲VRF̲Mentsuke.indb 17
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