Indoor Unit Main Pipes Selection; Main Pipes Selection; Outdoor Unit Pipe Connection; Remove Dirt Or Water In The Piping - Midea Mini VRF Technical & Service Manual

R410A All DC Inverter Mini VRF
Table 2: Indoor unit main pipes selection (L1~L5)
Total capacity of
downstream indoor units
(kW)
A＜16.6
16.6≤A＜23
Table 3: Main pipes selection (L1)
When the equivalent length of all liquid and air
Total capacity of
outdoor units
(kW)
gas side
A＜16
16≤A＜23
Note: Main pipe L1 can be selected form table 2 and table 3, the larger size should be finally selected.
The straight distance between copper pipe turning and the contiguous branch pipe is at least 0.5m.
The straight distance between the contiguous branch pipes is at least 0.5m.
The straight distance which the branch pipes connected to the indoor unit is at least 0.5m.
Table 4: Outdoor unit pipe connection
Piping side
MODEL
120 model
140 model
160 model
Outdoor Unit
120 model
140 model
160 model
If ODU connect more than one IDU, the capacity of each IDU should be not more than 8kW for refrigerant uniform
distribution.
When capacity of indoor unit greater than the sum of 100%, capacity of indoor unit will be attenuated.
When capacity of indoor unit greater than or equal to the sum of 120%, in order to ensure the effectiveness of
machine, and then try to open the indoor units at different time.

4.4 Remove Dirt or Water in the Piping

Make sure there is no any dirt or water before connecting the piping to the outdoor units.
Wash the piping with high pressure nitrogen, never use refrigerant of outdoor unit
4.5 Airtight Test
Charge pressured nitrogen after connecting indoor/outdoor unit piping to do airtight test.
Cautions:
1. Pressured nitrogen [4.3MPa (44kg/cm
2. Tighten high pressure/low pressure valves before applying pressured nitrogen.
3. Apply pressure from air vent mouth on the high pressure/low pressure valves.
4. The high pressure/low pressure valves are closed when applying pressured nitrogen.
5. The airtight test should never be used any oxygen, flammable gas or poisonous gas.
4.6 Vacuum
Using vacuum pump to do the vacuum and never using refrigerant to expel the air.
Vacuum should be done from both liquid side and gas side simultaneously.
52
Gas pipe
Φ15.9
Φ19.1
pipes < 90m
liquid side
(mm) (mm)
Φ15.9 Φ9.53
Φ19.1 Φ9.53
Gas Side
Maximum Quantity of Indoor unit
3
) for R410A] should be used in the airtight test.
Main pipe size(mm)
Liquid pipe
The first line
branch pipe
FQZHN-01D
FQZHN-01D
Outdoor unit pipe connection (mm)
Φ15.9
Φ15.9
Φ19.1
7
8
9
Φ9.53
Φ9.53
When the equivalent length of all liquid and air
pipes ≥ 90m
gas side liquid side
(mm) (mm)
Φ19.1 Φ9.53
Φ22.2 Φ9.53
Liquid Side
Φ9.53
Φ9.53
Φ9.53
Total Capacity of Indoor unit
45%~130%
45%~130%
45%~130%
.
MCAC-VTSM-2016-02
Branch Pipe
FQZHN-01D
FQZHN-01D
The first line
branch pipe
FQZHN-01D
FQZHN-02D
Installation