Toshiba MMY-MAP0806FT8P-E Installation Manual page 15

Able to detect a serious leakage
1. Apply pressure 0.3 MPa (3.0 kg/cm G) for 5 minutes or more.
2
2. Apply pressure 1.5 MPa (15 kg/cm 2 G) for 5 minutes or more.
Available to detect slow leakage
3. Apply pressure 3.73 MPa (38 kg/cm 2 G) for approx. 24 hours.
• 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 0.01 MPa (0.1 kg/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, are retightening
or other methods. After sealing, execute an airtight test again.
27-EN
2 G) per 1 °C. Consider the pressure change when checking
Vacuum drying
• Be sure to use a vacuum pump equipped with the counter- ow prevention function so that oil in the pump will
not ow 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 nishing 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 gure 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
Ball valve of suction gas side
• 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 suction gas side, discharge gas side, liquid 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 con rm 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 nishing the above procedure of vacuuming, exchange the vacuum pump with a refrigerant canister and
advance to the additional charging of refrigerant.
– 14 –
Low pressure
Connected to
Suction gas side valve
indoor unit
fully closed
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
Connected to
pipe side
Balanced pipe side valve fully
other follower
Piping
closed
units
at site
High pressure
gauge gauge
Gauge
V V
L H
manifold
P
Vacuum
pump
EN
ID
ID
28-EN