Mitsubishi Electric PFAV-P250VM-E Data Book page 85

1-2-3. PUHY-P-YHM's refrigerant charging calculation
Sample connection (with PFAV-P600VM-E-F)
OU OU
A
B
Outdoor Twinning Kit
CMY-Y100VBK2
Amount of refrigerant to be charged
Refrigerant for extended pipes (field piping) is not factory-charged to the outdoor unit. Add an appropriate amount of refrigerant
for each pipe on site.
Record the size of each liquid pipe and the amount of refrigerant that was charged on the outdoor unit for future reference.
Calculating the amount of refrigerant to be charged
The amount of refrigerant to be charged is calculated with the size of the on-site-installed liquid pipes and their length.
Calculate the amount of refrigerant to be charged according to the formula below.
Round up the calculation result to the nearest 0.1kg. (i.e., 16.08 kg = 16.1 kg)
<Amount of refrigerant to be charged>
Calculating the amount of refrigerant to be charged
Total length of ø19.05
Total length of ø15.88
liquid pipe x 0.29
liquid pipe x 0.2
+
(m)x0.29(kg/m) (m)x0.2(kg/m)
Amount of factory-
charged refrigerant
Outdoor unit model Charged amount
P250 model 9.0kg
P350 model 11.5kg
P400 model 11.5kg
Note1. "-"
Note2. If the A/C system is designed to use Cooling-mode under Outside temperature 0˚C, H'<=15m.
Note3. As bents cause pressure loss on transportation of refrigerant, fewer bents design is better;
Piping length needs to consider the actual length and equivalent length which bents are counted.
Equivalent piping length (m)=Actual piping length+"M" x Quantity of bent.
OK
Downward
incline
Install the pipes from the outdoor unit to the branch
joint with a downward incline.
IU
C
P600-F
Total length of ø12.7
liquid pipe x 0.12
+ +
(m)x0.12(kg/m)
Sample calculation
A : ø9.52 3m
B : ø9.52 2m
C : ø15.88 2m
Total length for ø15.88
each pipe size : ø9.52
This yields the following result :
NG
To indoor unit To indoor unit
Upward
incline
Total length of ø9.52 Total length of ø6.35
liquid pipe x 0.06 liquid pipe x 0.024
+
(m)x0.06(kg/m) (m)x0.024(kg/m)
C=2m
A+B=5m
=2x0.2+5x0.06+5.0
=5.7kg
83
Trap (gas
pipe only)
To indoor unit
2m 2m max
If the length of pipe between the branch joint and outdoor
unit exceeds 2 m, provide at rap at a distance 2 m or less
from the branch joint.
Model connected Amount for the
indoorunits indoor unit
+
P250, P300-F 3.0kg
P500, P600-F 5.0kg
P750, P900-F 8.0kg
To indoor unit