Refrigerant Piping - Hitachi AirCore 700 Installation & Maintenance Manual

4. Installation Instructions

4.5 Refrigerant Piping

1. Piping requirement
Model
2.0/2.5/3.0HP
4.0/5.0/6.0/6.5HP
•
The shorter the refrigerant piping is, the better the performance will be. So the connecting pipe
should be as short as possible.
Indoor unit
Height difference H
Additional refrigerant charge
•
The unit has been filled with refrigerant, but if the pipe exceeds 30m, additional refrigerant (R32)
charge is required.
For 2.0~3.0HP, additional refrigerant charge =(L-30)×18g/m
For 4.0~6.5HP, additional refrigerant charge =(L-30)×35g/m
Oil trap
•
When the indoor unit is lower than outdoor unit and
height difference is larger than 5m, set an oil trap every
5m (height difference) on suction piping.
NOTES:
•
To avoid storing too much oil in the oil trap, the oil trap should be as short as possible.
•
The horizontal piping should slope down along the refrigerant flow direction, to bring the oil back to
compressor, the slope is about 1/200 to1/250.
2. Piping material
•
Prepare locally-supplied copper pipes.
•
Select clean copper pipes. Make sure that there is no dust and
moisture inside of the pipes. Blow the inside of the pipes with
nitrogen or dry air to remove any dust or foreign materials before
connecting pipes.
•
Piping thickness and material of the pipe are shown right.
CAUTION
!
When installing pipe through the wall,
secure a cap at the end of the pipe.
Correct
Wall hole
Wall hole
Attach a cap or vinyl tape
Outer diameter of pipe (mm)
Gas
12.7
15.88
Pipe length L
Outdoor unit
Do not place the pipe directly on the ground
Correct
Incorrect
Attach a cap or vinyl tape
Liquid
6.35
9.52
Refrigerant piping between indoor unit and outdoor unit
Max. pipe
Model
length (L)
2.0~2.5HP 50 (m)
3.0HP 75 (m)
4.0~6.5HP 75 (m)
Slope: 1/200~1/250
Incorrect
-14-
Max. height Add. refrigerant
difference (H) (exceed 30m)
30 (m) 18 (g/m)
30 (m) 18 (g/m)
30 (m) 35 (g/m)
Slope: 1/200~1/250
Oil trap
Oil trap
(Unit: mm)
Diameter Thickness
φ6.35 0.7
φ9.52 0.8
φ12.7 0.8
φ15.88 1.0
Correct Incorrect
Rain water
can enter
Attach a cap
or vinyl bag
with rubber band