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and the number of bends, and enlarge the diameter of bends.
The permitted maximum value of each case:
The pipe meld type could be employed for the connection of the pipes between the indoor and
outdoor units.
The pipe joint should be tightly connected when a pipe joint is employed between two pipes. It is
better to use only one connecting pipe if the distance is not far.
The pipes should not be shriveled when the pipes are connecting. The bend diameter should be
longer than 200 millimeter. The connecting pipes should not be extended or curved frequently and
the curving process should not be larger than 3 times in the same bending position.
4).Vacuum evacuating, leakage testing and refrigerant charging
The system is charged with nitrogen gas from the low-pressure valve until the pipe pressure
increasing to 1Mpa, and the leakage is examined at the connecting or welding position with soap
water. The air is evacuated in the pipe from the check valve with a vacuum pump if no leakage exists,
then loosens the cores of the liquid valve and gas valve and clears the soap water with dry cloth.
If the vacuum pumps and high-pressure nitrogen are not available, we can operate as following:
Remove the cores of the liquid valve and gas valve and loosen the cores of check valve on the
gas valve and the gas will exhaust. Keep exhausting for 15 seconds, tightening the check valve
as refrigerant gas coming out.
Loosen the liquid valve and gas valve.
Tighten the bonnet of the valve, and examine the air leakage at the connecting position with
soap water or gas leakage detector, then clear the soap water with dry cloth.
Wrap the flare nut with insulation material to avoid the condensation dropping after finishing the
preceding procedure.
The refrigerant in the conditioner unit is enough for the connecting pipes of 7.5 meters, if the pipe is
longer than 7.5 meters, additional supplement refrigerant should be supplied. The maximum pipe length
is 50 meters. When the height difference between the indoor unit and outdoor unit is larger than 10
meters, an oil bend should be employed for every 6 meters.
Additional supplement refrigerant as per the extended connection pipe:
Item
Height difference between the indoor and outdoor unit
0
90
Number of bends
Length of connecting pipes
Oil bend
Indoor
Size of Fitting Pipe
(mm)
Outdoor
Oil bend
Max.
Max. Height
Pipe
Difference
Length (m)
between
38
＜30M
＜12
＜50M
Amount of
Additional
Refrigerant to be
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