Midea MV8M-160WV2N1 - Page 110

V8 Mini R410A VRF 50Hz
108
Midea
V8 Mini
Series Engineering Data Book
7.2 Adding Refrigerant
Caution
 Only charge refrigerant after performing a gastightness test and vacuum drying.
 Never charge more refrigerant than required as doing so can lead to liquid hammering.
 Only use refrigerant R410A - charging with an unsuitable substance may cause explosions or accidents.

Use tools and equipment designed for use with R410A to ensure required pressure resistance and to prevent
foreign materials from entering the system.
 Refrigerant must be treated in accordance with applicable legislation.
 Always use protective gloves and protect your eyes when charging refrigerant.
 Open refrigerant containers slowly.
 The power supply for all outdoor units should be turned on, when add refrigerant.
Procedure
The procedure for adding refrigerant is as follows:
Step 1
 Calculate additional refrigerant charge R (kg) (see Part 3, 7.1 “Calculating Additional Refrigerant Charge”)
Step 2

Place a tank of R410A refrigerant on a weighing scale. Turn the tank upside down to ensure refrigerant is charged
in a liquid state. (R410A is a blend of two different chemicals compounds. Charging gaseous R410A into the
system could mean that the refrigerant charged is not of the correct composition).
 After vacuum drying (see Part 3, 4.10
“Vacuum Drying”), the blue and red pressure gauge hoses should still be
connected to the pressure gauge and to the master unit stop valves.
 Connect the yellow hose from the pressure gauge to the R410A refrigerant tank.
Step 3

Open the valve where the yellow hose meets the pressure gauge, and open the refrigerant tank slightly to let the
refrigerant eliminate the air. Caution: open the tank slowly to avoid freezing your hand.
 Set the weighing scale to zero.
Step 4
· Open the three valves on the pressure gauge to begin charging refrigerant.
·
When the amount charged reaches R (kg), close the three valves. If the amount charged has not reached R (kg)
but no additional refrigerant can be charged, close the three valves on the pressure gauge, run the outdoor units
in cooling mode, and then open the yellow and blue valves. Continue charging until the full R (kg) of refrigerant
has been charged, then close the yellow and blue valves. Note: Before running the system, be sure to complete
all the pre-commissioning checks as listed in Part 3 “Pre-commissioning Checks” and be sure to open all stop
valves as running the system with the stop valves closed would damage the compressor.
Figure 3-7.1: Charging refrigerant
Pressure gauge
Notes for installers
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