Vacuum Drying; Adding Refrigerant - Toshiba MMY-MAP0804FT8-E Installation Manual

 Vacuum drying
• Be sure to use a vacuum pump equipped with the counter-flow prevention function so that oil in the pump will
not flow back into piping for air conditioners. (If oil in the vacuum pump enters in the air conditioner with R410A
refrigerant, a problem may be caused in the refrigerating cycle.)
After finishing the airtight test and discharging nitrogen gas, connect the gauge manifold to the service ports of the liquid side,
discharge gas side, suction gas side, and balance pipe side and connect a vacuum pump as shown in the figure below. Be sure
to perform vacuuming for the liquid, discharge gas side, suction gas side, and balance pipe sides.
To gauge
Packed valve
To outdoor
manifold
details
unit
Liquid-side
To
service port
outdoor To outdoor unit
unit
Liquid-side
valve
To
Service port of
gauge
discharge gas side
manifold
Piping at Ball valve of
site
discharge gas side
Piping
at site
Service port of
suction gas side
Piping
Ball valve of
at site
Piping
suction gas side
at site
• Use a vacuum pump with a high vacuuming degree [-100.7 kPa (5 Torr, -755 mmHg)] and large exhaust gas
amount (40 L/minute or larger).
• Perform vacuuming for 2 or 3 hours, though the time differs depending on the pipe length. Check that all the
valves at the liquid side, discharge gas side, suction gas side, and balance pipe side are fully closed.
• If the pressure does not reach 100.7 kPa or less even after vacuuming for over 2 hours, continue vacuuming for
1 hour or more. If the pressure does not reach -100.7 kPa after 3 hours of vacuuming, stop vacuuming and check
for air leakage.
• If the pressure reaches -100.7 kPa or less after vacuuming for 2 hours or more, close the valves VL and VH on
the gauge manifold fully and stop the vacuum pump. Leave it as it is for 1 hour to confirm that the vacuuming
degree does not change.
If the degree of vacuum loss is large, moisture may remain in the pipes. In that case, inject dry nitrogen gas and
apply pressure to 0.05 MPa and perform vacuuming again.
• After finishing the above procedure of vacuuming, exchange the vacuum pump with a refrigerant canister and
advance to the additional charging of refrigerant.
• To protect the world's environment, do not release chlorofluorocarbons into the atmosphere.
• Do not do an air purge including used refrigerant.
31-EN
Low pressure
gauge
Connected to
Suction gas side
indoor unit valve fully closed
Main
Header outdoor unit
pipe
Brazed
Service port
Fully
closed
Service port
Discharge gas side valve
Service port
fully closed
Fully
of balance
closed
pipe side
Liquid side valve
To
fully closed
outdoor
Fully
unit
closed
Packed valve
of balance
Balanced pipe side
pipe side
Connected to
valve fully closed
other follower
units
 Adding refrigerant
After finishing vacuuming, exchange the vacuum pump with a refrigerant canister and start additional charging of refrigerant.
Calculation of additional refrigerant charge amount
Refrigerant charge amount factory default does not include the refrigerant for pipes at the local site.
For refrigerant to be charged in pipes at the local site, calculate the amount and charge it additionally.
NOTE
If the additional refrigerant amount indicates minus as the result of calculation, use the air conditioner without additional
refrigerant.
High pressure
gauge
Outdoor unit type
Charging amount (kg)
V V
Gauge
L H
manifold
Additional refrigerant
charge amount at local site
Table 1
P
Liquid pipe dia. (mm)
Vacuum pump
Additional refrigerant amount / 1 m
liquid pipe (kg/m)
– 16 –
MAP080 MAP100 MAP120
11.0
Additional refrigerant
= ×
Real length of liquid pipe charge amount per 1 m
liquid pipe (Table 1)
6.4 9.5 12.7
0.025 0.055 0.105
MAP140
Corrective amount of
refrigerant depending on HP
× +
1.3
of co-operating outdoor units
(Table 2)
15.9 19.1 22.2
0.160 0.250 0.350
32-EN