Toshiba RBC-TWP50E2 Installation Manual page 5

Additional Refrigerant Amount
<Formula for Calculating Additional Refrigerant Amount>
Do not remove the refrigerant even if the additional refrigerant amount becomes
minus result as a result of calculations by the following formula and operate the
air conditioner as it is.
Additional refrigerant amount (kg) = Main piping additional refrigerant
A: Additional refrigerant amount per meter of actual main piping length (kg)
B: Additional refrigerant amount per meter of actual branch piping length (kg)
L: Actual length of main piping (m)
a, b: Actual length of branch piping (m)
Standard piping length
R410A
Model
Main piping
80 AT
28m
110 AT
140 AT
28m
160 AT
Standard piping length
R32
Model
Main piping
80 AT
28m
110 AT
140 AT 28m
CAUTION
1. Be certain to write the additional refrigerant amount, pipe length (actual
length), head and other specification on the nameplate put on the outdoor unit for recording.
2. Seal the correct amount of additional refrigerant in the system.
Gas Leak Test
• Use a leak detector manufactured specially for the HFC refrigerant (R32, R410A, R134a, etc.) when testing R32, R410A.
The sensitivity of leak detectors for previous HCFC refrigerants (such as R22) lowers to about 1/40 when used with
HFC refrigerants and these detectors cannot be used.
amount (kg) + Branch piping additional
refrigerant amount (kg)
= A × (L – 28) + B × (a + b – 4)
Additional refrigerant
amount per Meter (kg/m)
Branch
A
piping
2m 0.040
2m 0.040
Additional refrigerant
amount per Meter (kg/m)
Branch
A
piping
2m 0.035
2m 0.035
– 5 –
Indoor unit B
Branch
piping
B
0.020
0.040
Outdoor unit
B
0.020
0.035
Indoor unit A
Branch pipe
a
b
Branch
piping
H
L
Main
piping