Toshiba MMY-MAP0806FT8P-E Installationsanleitung Seite 70

Able to detect a serious leakage
1. Apply pressure 0.3MPa (3.0kg/cm 2 G) for 5 minutes or more.
2. Apply pressure 1.5MPa (15kg/cm 2 G) for 5 minutes or more.
Available to detect slow leakage
3. Apply pressure 3.73MPa (38kg/cm G) for approx. 24 hours.
2
• If there is no pressure decrease after 24 hours, the test is passed.
NOTE
However, if the environmental temperature changes from the moment of applying pressure to 24 hours after that,
the pressure will change by about 0.01MPa (0.1kg/cm
the test result.
REQUIREMENT
When pressure decrease is detected in steps 1-3, check the leakage at the connecting points.
Check the leakage using a foaming agent or other measures and seal the leak with re-brazing, flare retightening
or other methods. After sealing, execute an airtight test again.
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2 G) per 1°C. Consider the pressure change when checking
– 69 –
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
suction gas side, discharge gas side, liquid side and balance pipe side and connect a vacuum pump as shown
in the figure below. Be sure to perform vacuuming for the suction gas side, discharge gas side, liquid side and
balance pipe side.
To gauge
Packed valve details
To outdoor
manifold
unit
To
Liquid-side
outdoor
service port
To outdoor unit
unit
Liquid-side
valve
To
Service port
gauge
of discharge
gas side manifold
Ball valve of
Piping at site discharge
gas side
Piping
at site
Service port of suction gas side
Piping
at site
Piping
Ball valve of suction gas side
at site
• Use a vacuum pump with a high vacuuming degree [-100.7kPa (5Torr, -755mmHg)] and large exhaust gas
amount (40L/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 suction gas side, discharge gas side, liquid side and balance pipe side are fully closed.
• If the pressure does not reach -100.7kPa or less even after vacuuming for over 2 hours, continue vacuuming for
1 hour or more. If the pressure does not reach -100.7kPa after 3 hours of vacuuming, stop vacuuming and check
for air leakage.
• If the pressure reaches -100.7kPa 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 0.05MPa 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.
Low pressure
gauge
Connected to
Suction gas side valve
indoor unit
fully closed
V
Main
Header outdoor unit
pipe
Brazed
Service port
Fully
closed
Service port
Service
Discharge gas side valve
port
fully closed
Fully
of balance
closed
pipe side
Service port
To
Liquid side valve fully
outdoor
closed
Fully
unit
closed
Packed
Service port
valve
of balance
pipe side Connected to
Balanced pipe side valve fully
other follower
closed
units
High pressure
gauge
Gauge
V
L H
manifold
P
Vacuum
pump
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