Air Purge - Toshiba MCY-MAP0401HT Installation Manual

3
REFRIGERANT PIPING

Air purge

For the air purge at installation time (Discharge of air in connecting pipes), use "Vacuum pump method" from
viewpoint of the protection of the earths environment.
• For protection of the earths environment, do not discharge the refrigerant gas in the air.
• Using a vacuum pump, eliminate the remaining air (nitrogen gas, etc.) in the unit. If gas remains, performance
and reliability of the unit may be reduced.
After the airtight test, discharge nitrogen gas. Then connect the gauge manifold to the service ports at suction gas
side, discharge gas side and liquid side, and connect the vacuum pump as shown in the following figure.
Be sure to perform vacuuming for suction gas side, discharge gas side and liquid side.
• Be sure to perform vacuuming from both suction gas side, discharge gas side and liquid side.
• Be sure to perform vacuuming from both liquid and gas sides.
• 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 when the pump has been stopped. (If oil in the vacuum pump enters in to the air conditioner
with R410A refrigerant, an error may occur in the refrigeration cycle.)
Connected to indoor unit
Main pipe
• Use a vacuum pump that has a high vacuum (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,
detect and repair the leak.
• When the vacuuming valve has reached -755mmHg or less after vacuuming for 2 hours or more, close valves VL
and VH on the gauge manifold fully. Stop the vacuum pump, leave it as it is for 1 hour and then check the vacuum
does not change. If it does change then there may be a leak within the system.
• After the above procedure for vacuuming has finished, exchange the vacuum pump with a refrigerant cylinder and
advance to the additional charging of refrigerant.
Packed valve fully closed
(Gas side)
Outdoor unit
Brazed
Service port
Fully closed
Ball valve fully closed
(Liquid side)
Low-
pressure
gauge
VL
Service port
17
High-
pressure
gauge
VH
Gauge manifold
P
Vacuum pump