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3P477778-7G English
8 . Precautions on refrigerant piping
•
Do not allow anything other than the designated refrigerant to get
mixed into the refrigerant cycle, such as air, nitrogen, etc. If any
refrigerant gas leaks while working on the unit, ventilate the room
thoroughly right away.
•
Use R410A only when adding refrigerant.
•
Installation tools:
Make sure to use installation tools (gauge manifold, charge hose,
etc.) that are exclusively used for R410A installations to withstand
the pressure and to prevent foreign materials (e.g., mineral oils and
moisture) from mixing into the system.
•
Vacuum pump:
- Use a 2-stage vacuum pump with a non-return valve.
-
Make sure the pump oil does not flow oppositely into the system
while the pump is not working.
- Use a vacuum pump which can evacuate to 500 microns.
Protection against contamination when installing pipes
Take measures to prevent foreign materials like moisture and contami-
nation from mixing into the system.
Installation
Protection method
More than a month
Pinch the pipe
Less than a month
Pinch or tape pipe
Regardless of the period
Block all gaps in the holes for passing out piping and wiring using seal-
ing material (field supply) (the capacity of the unit will drop and small
animals may enter the machine).
Example:
passing piping out through the front.
1
1 Close the areas marked with
.
(When the piping is routed from the
front panel.)
•
Use clean pipes only.
•
Hold the pipe end downwards when removing burrs.
•
Cover the pipe end when inserting it through a wall so that no dust
or dirt enters the pipe.
NOTE
•
After all the piping has been connected, make sure there is no gas
leak. Use Dry Nitrogen to perform a gas leak detection.
•
After knocking out the holes, we recommend you remove burrs in
the knock holes and paint the edges and areas around the edges
using the repair paint.
8 .1 . Caution for brazing
•
Make sure to blow through with Dry Nitrogen when brazing. Blowing
through with Dry Nitrogen prevents the creation of large quantities
of oxidized film on the inside of the piping. An oxidized film ad
-
versely affects valves and compressors in the refrigerating system
and prevents proper operation.
•
The Dry Nitrogen pressure should be set to 2.9 psi (0.02 MPa (i.e.,
just enough so it can be felt on the skin)) with a pressure-reducing
valve.
1
2
3
4
5
6
6
1 Refrigerant piping
2 Part to be brazed
3 Taping
4 Hands valve
5 Pressure-reducing valve
6 Dry Nitrogen
Do not use anti-oxidants when brazing the pipe joints. Residue can
clog pipes and break equipment:
• Do not use flux when brazing copper-to-copper refrigerant piping.
Use phosphor copper brazing filler alloy (BCuP) which does not
require flux.
• Flux has an extremely harmful influence on refrigerant piping
systems. For instance, if chlorine based flux is used, it will cause
pipe corrosion or, in particular, if the flux contains fluorine, it will
deteriorate the refrigerant oil.
8 .2 . Connecting the refrigerant piping
8 .2 .1 .
Decide front or side (bottom) connection
Installation of refrigerant piping is possible as front connection or side con-
nection (when taken out from the bottom) as shown in the figure below.
1
2
3
1 Left-side connection
2 Front connection
3 Right-side connection
•
For side connections, the knockout hole on the bottom plate should
be removed:
3
2
1
1
4
1
Knockout hole (Piping)
2
Drill
3
Points for drilling
4
Knockout hole (Power supply
wiring)
NOTE
Precautions when knocking out knockout holes:
•
Be sure to avoid damaging the casing.
•
After knocking out the knockout holes, we recommend you remove
the burrs and paint the edges and areas around the edges using
repair paint to prevent rusting.
•
When passing electrical wiring through the knock holes, protect the wir-
ing with a conduit or bushings, making sure not to damage the wiring.
8 .2 .2 . Remove the pinched pipes
WARNING
Any gas or oil remaining inside the stop valve may blow off the pinched
piping.
Failure to observe the instructions in procedure below properly may
result in property damage or personal injury, which may be serious
depending on the circumstances.
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