Install Instructions

2.7 Vacuum drying works
2.7.1 What is Vacuum drying?
Vacuum drying is : The use of a vacuum pump to vaporize(gasify) the moisture (liquid) inside the pipe and expel it leaving
the pipes completely dry inside.
At 1 atm(760mmHg) the boiling point (evaporating temperature) of water is 100℃(212℉) but if a vacu-
um is created inside the pipes using a vacuum pump then the boiling point is rapidly reduced as the
degree of the vacuum is increased.
If the boiling point is reduced to a level below that of the ambient temperature then the moisture in the
pipes will evaporate.
40 (104)
30 (86)
26.7(80.1)
24.4(75.9)
22.2(72)
20.6(69.1)
17.8(60)
15.0(59)
11.7(53.1)
7.2(45.1)
0(32)
Absolute pressure (mmHg)
Temperature
-20(-4)
760
755
740
720
710
700
690
680
670
660
560
460
360
260
160
60
0
-10(14) 0(32) 10(50) 20(68) 30(86) 40(104) 50(122) 60(140) 70(158)
0 mmHg
mmHg
5
10
20
30
40
50
60
70
90
100
200
300
400
500
600
700
760mmHg
x
Required degree
of vaccum
3.8MPa(551.1psi)
Outside
temperature
range
Evaporation
point
(°C(°F))
Gauge pressure (mmHg) )
730
730
730
Key point: Maintain a vacuum level of -755mmHg
NOTE
2. Guideline for each installation process
30 _ Heat pump 60Hz/R410A
Installation of
Outdoor Units
SINGLE ZONE
Boilng point of
water(°C(°F))
-705 7333 55
-724 4800 36
-735 3333 25
-738 3066 22
-740 2666 20
-742 2400 18
-745 2000 15
-747 1733 13
-750 1333 10
-752 1066 8
-755 667 5
Pressure
The degree
of a vacuum
mmHg Pa psi Torr
Example
When outside temperature is 11.7℃(53.1℉) as shown
in the table on the right , the degree of vacuum must be
lowered below -750mmHg
The evacuation of air conditioner piping provides the fol-
lowing effects.
1. Vaccum drying
2. Removes air and nitrogen(used in air-tightness test)
from the inside of pipes.
Therefore , it is necessary to ensure that both purposes
have been achieved in the vacuum drying operation.
1.1
0.7
0.5
0.4
0.4
0.3
0.3
0.3
0.2
0.2
0.1