Hitachi Set Free mini-HNRQ1 Series, Service Manual

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18
INSTALLATION
3. Refrigerant Piping Work
●
The design pressure for this product is 4.15MPa. The pressure required for refrigerant R410A is 1.4
times higher than that of the refrigerant R22. That means that the refrigerant piping for R410A must be thicker
than that for R22. Make sure to use specified refrigerant piping. Otherwise, the refrigerant piping may
rupture due to an excessive refrigerant pressure. Pay close attention to the piping thickness when using
copper refrigerant piping.
●
Ensure that the stop valves are closed before removing the flare nut of the stop valves.
●
When handling the refrigerant, be sure to wear leather gloves to prevent injuries.
3.1 Precaution for Refrigerant Piping
(1) Use the copper pipe for refrigerant piping.
(2) Keep the copper pipes clean. 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 cutting tools such as a grinder or saw which could produce metal particles.
(3) Take special care to prevent pollution or moisture settling from going into the interior pipe during piping
work.
(4) Avoid performing the piping connection work for outdoor unit in the rain.
(5) Refrigerant pipe ends
.
(6) Piping Thickness and Material
The thickness of refrigerant pipe differs depending on design pressure. For copper tube, pay attention to
pipe selection, because the piping thickness differs depending on its material.
Diameter
(Φd)
R410A
Thickness Temper
6.35 mm 0.8 mm O
9.52 mm 0.8 mm O
12.7 mm 0.8 mm O
15.88 mm 1.0 mm O
19.05 mm 1.0 mm 1/2H
22.2 mm 1.2 mm 1/2H
25.4 mm 1.2 mm 1/2H
Notes:
● Do not use the pipe with allowable pressure is less than 4.15MPa.
● The reference value of the refrigerant piping thickness is indicated in the table.
● Do not use the pipe which is considerably different from the reference value.
WARNING
!
CAUTION
!
When installing pipe through the wall,
secure a cap at the end of the pipe.
Correct
Incorrect
Hole
Hole
Attach a cap or vinyl tape
Do not place the pipe
directly on the ground
Correct Incorrect
Attach a cap or vinyl tape
Attach a cap
or vinyl bag
with rubber band
Correct Incorrect
Rain water
can enter