Installation Guide
Table Of Contents
28
Air Tightness Test, Vacuuming
and Supplementing Refrigerant
Supplementing refrigerant
Principles:
Before delivery, the ODUs have been charged with a certain amount of refrigerant, but which
cannot meet the needs of extended pipes. So refrigerant has to be added according to the
actual length of refrigerant piping at installation site.
Steps:
● Close compound pressure gauge, replace vacuum pump with charge tank connected
with charging pipe. Make sure the air is drained completely, and connect the joints of
charge tanks and put the tank mouth down on the platform scale.
● Set the quantity to be filled at the electronic scale, and successively open the valve of
charge tank and valve of compound pressure gauge to fill the system with refrigerant.
When reaching the limits, immediately close valve of charge tank and disconnect
connection pipes.
Notes:
● For refrigerant tank with siphon: the tank needs not to be put upside down because
the siphon can reach the tank bottom.
● If using R410A charge tank without siphon, make sure the tank is put upside down in
the charge process, which is shown as below:
To IDU
To IDU
Overhaul
val ve hole
St op val ve
St op val ve
Gas pipe
Liq uid pi pe
ODU
Compo und
pre ssure g auge
Refr ige rant
cha rge
ta nk
Sip hon
Calculation of the refrigerant amount to be supplemented (R410A):
Liquid pipe diameter (mm) 6.35 9.52 12.7 15.88 19.05 22.23 25.4
Supplemented refrigerant
quantity (g/m)
22 57 110 170 260 360 520
Supplemented refrigerant amount = Σ Liquid pipe length at various diameters x
Supplemented refrigerant amount per meter
Notes:
1. For single modular units, the maximum refrigerant amount (unit + total supplemented
amount) should not be greater than 52 kg. Otherwise, the units fail to run reliably.
2. For multi-modular units, when the calculated added refrigerant is over 40 kg, the
actually added refrigerant volume should be the 80% of the calculated value or 40 kg
(whichever is greater).
For example, if the calculated value of the additional refrigerant volume is 45 kg, 45 x
0.8 = 36 kg, and the actually added refrigerant volume is 40 kg.
If the calculated amount of the supplemented refrigerant is 60 kg and 60 x 0.8 = 48 kg,
the actually refrigerant amount is 48 kg.