Toshiba MMY-MAP0501HT7 Installation Manual page 20

5
REFRIGERANT PIPING
Air purge
For the air purge at installation time (Discharge of air in connecting pipes), use "Vacuum pump method" from
viewpoint of protection of earth environment.
• For protection of earth environment, do not discharge the flon gas in the air.
• Using a vacuum pump, eliminate the remained air (nitrogen gas, etc.) in the unit. If gas remains, an absence
of faculties may be caused.
After the airtight test, discharge nitrogen gas. Then connect the gauge manifold to the service ports at liquid, gas,
and balance sides, and connect the vacuum pump as shown in the following figure. Be sure to perform vacuuming
for liquid, gas and balance sides.
• Be sure to perform vacuuming from both liquid and gas sides.
• Be sure to use a vacuum pump with counter-flow preventive function so that oil in the pump does not back up in
the pipe of the air conditioner while the pump stops. (If oil in the vacuum pump enters in the air conditioner with
R410A refrigerant, a trouble is caused in the refrigerating cycle.)
Detailed drawing of packed valve
To gauge manifold
Liquid-side
service port
Liquid-side
packed valve
Balance
service port
Balance
packed valve
Piping at site
• Use a vacuum pump having a high vacuuming degree (below -755mmHg) and a large exhaust gas amount (over
40L/minute).
• Perform vacuuming for 2 or 3 hours though time differs due to pipe length. In this time, check all packed valves at
liquid, gas, and balance sides are fully closed.
• If vacuuming valve amount is not decreased to below -755mmHg even after vacuuming for 2 hours or more,
continue vacuuming for 1 hour or more. If -755mmHg or less cannot be obtained by 3 hours or more vacuuming,
check the leaked position.
• When vacuuming valve reached to -755mmHg or less after vacuuming for 2 hours or more, close valves V
V of the gauge manifold fully, stop the vacuum pump, leave it as it is for 1 hour, and then check the vacuuming
H
degree does not change. If it changed, there may be a leaked position. Check the leaked position.
• After the above procedure of vacuuming has finished, exchange the vacuum pump with a refrigerant cylinder and
advance to the additional charging of refrigerant.
Connected to indoor unit
Main pipe
Gas-side service port
Gas-side
packed valve
or ball valve
To outdoor
unit
To
outdoor
unit
Piping
Piping
at site
at site
To outdoor unit
Connected to other follower outdoor units
Packed valve fully closed
(gas side)
Header outdoor unit
Brazed
Service
port
Fully
closed
Packed valve fully closed
(liquid side)
Fully
closed
Packed valve fully closed
(Balance)
17
Low- High-
pressure pressure
gauge gauge
V V
L H
Service port
Vacuum pump
Gauge
manifold
P
and
L