Remove Dirt Or Water In The Pipe; Airtight Test; Air Purge With Vacuum Pump; Refrigerant Amount To Be Added - Midea M-thermal Split MHA-V4W/D2N8 Installation And Owner's Manual

Models
Max.piping length
Max difference in height
when outdoor unit is upsite
Max difference in height
when outdoor unit is downside
7.5 Remove Dirt or Water in the Pipes
1) Make sure there is no any dirt or water before connectiong the piping to the outdoor and indoor units.
2) Wash the pipes with high pressure nitrogen, never use refrigerant of outdoor unit.
7.6 Airtight Testing
Charge pressured nitrogen after connecting indoor/outdoor unit pipes to do airtight testing.
Pressured nitrogen [4.3MPa (44kg/cm ) for R32] should be used in the airtight testing.
Tighten high/low pressure valves before charging pressured nitrogen.
Charge pressure nitrogen from the connector on the pressure valves.
The airtight testing should never use any oxygen, flammable gas or poisonous gas.

7.7 Air Purge with Vacuum Pump

1) Using vacuum pump to do the vacuum,never using refrigerant to expel the air.
2) Vacuuming should be done from liquid side .

7.8 Refrigerant Amount to be Added

Calculate the added refrigerant according to the diameter and the length of the liquid side pipe of the outdoor unit/indoor unit connection.
If the length of the liquid side pipe is less than 15 meters it is no need to add more refrigerant ,so than calculating the added refrigerant the
length of the liquid side pipe must subtract 15 meters.
Model
4/6 kW
8/10 kW
4~10 kW
30m
20m
15m
CAUTION
2
Refrigerant to be added
20g/m
38g/m
14