Mitsubishi Electric PAC-IF013B-E Installation Manual page 14

6
Requirement on local AHU design
6.3 Requirement on DX (Direct expansion) coil
(1) Heat exchanger volume of DX coil
Make sure to keep the DX coil capacity within the following range.
If the piping length is 30m or shorter, DX coil capacity can be increased as follows.
Model capacity of outdoor unit
Max. volume [cm 3 ]
Pipe length
Min. volume [cm 3 ]
Note: Calculate them by linear interpolation in case of other piping lengths not shown on this table.
(2) Structure of DX coil
When multiple outdoor units are connected, basically select one interlaced DX coil which has multiple refrigerant circuit, or multiple coil placed in parallel to the
air flow. If multiple coils are placed in series with the air flow, maximum 2 coils in series are acceptable. (See figure 6-1.)
Interlaced
Air flow
OK
(3) Diameter of header
With a bigger size header, the refrigerant flow velocity decreases and this disturbs the sufficient circulation of refrigerant oil. As a result, the refrigerant oil
does not flow properly and could cause a serious damage of compressor.
Use the pipe whose outside diameter is less than the value shown in the table below.
Model capacity of outdoor unit
Max. diameter of header [mm]
Model capacity of outdoor unit
Max. diameter of header [mm]
(4) Withstanding pressure
Design pressure of outdoor unit is 4.15 MPa. Following must be satisfied for burst pressure of connecting application.
Burst pressure : More than 12.45 MPa (3 times more than design pressure)
(5) Contamination maintenance
1. Wash the inside of heat exchanger to keep it clean. Be sure to rinse not to leave flux. Do not use chlorine detergent when washing.
2. Be sure that the amount of contamination per unit cubic content of heat transfer pipe is less than the following amount.
Example) In case of ø9.52mm
Residual water : 0.6 mg/m, Residual oil : 0.5 mg/m, Solid foreign object : 1.8 mg/m
6.4 Additional refrigerant charging amount
Regarding additional refrigerant charging amount of PUZ-ZM100, 125, 140 models, follow the table below.
For other models, see the installation manual of each outdoor unit.
Permitted pipe
Model
length
ZM100 - 140 - 85m
14
ZRP 35 50
P – –
SHW – –
ZM 35 50
30m - 1050 1500
20m 1350 1800
10m 1650 2100
350 500
Parallel
Air flow
HP 1 HP 2
OK
<Fig. 6-1: Example of DX coil structure>
ZRP 35 50
P – –
SHW – –
ZM 35 50
Permitted vertical
difference
31 - 40m
- 30m 0.5kg
60 71 100
– – –
– 80 112
60 71 100
1800 2130 3000
2700 3030 3900
3600 3930 4800
600 710 1000
2 in series
Air flow
HP 1 2
HP 1 HP 2
60 71 100
– – –
– 80 112
{19
60 71 100
{14
Additional refrigerant charging amount
41 - 50m 51 - 60m 61 - 70m
1.0kg 1.5kg 2.0kg
125 140 200
– – 200
140 – 230
125 140 –
3750 4200 6000
4650 5100 7800
5550 6000 9600
1250 1400 2000
3 in series
Air flow
3 4 HP 1
OK NOT OK
125 140 200
– – 200
140 – 230
{28
125 140
{21
◎ Maximum
amount of
71 - 85m
refrigerant
2.8kg 6.8kg
250
250
–
–
7500
9300
11100
2500
2 3
250
250
–