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Idiomas disponibles
Idiomas disponibles
Able to detect a serious leakage
1. Apply pressure 43.5 psi (0.3 MPa) for 5 minutes or more.
2. Apply pressure 217.5 psi (1.5 MPa) for 5 minutes or more.
Available to detect slow leakage
3. Apply pressure 601 psi (4.15 MPa) 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 1.45 psi (0.01 MPa) per 1.8°F. Consider the pressure change when checking
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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– 15 –
Vacuum drying
Be sure to perform vacuuming from both liquid and gas sides.
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 and gas side and connect a vacuum pump as shown in the figure below. Be sure to perform vacuuming
for the liquid and gas pipe sides.
Valve details
To gauge
manifold
To outdoor unit
Liquid-side
Liquid-side
valve
Gas-side valve
service port
To
outdoor
unit
Gas-side
Piping at site
service port
Piping at site
Use a vacuum pump with a high vacuuming degree [14.6 psi (5 Torr, -755 mmHg)] and large exhaust gas amount
(10.5 gal (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
packed valves at the liquid side and gas side are fully closed.
If the pressure does not reach 14.6 psi or less, continue vacuuming for 1 hour or more. If the pressure does
not reach 14.6 psi after 3 hours of vacuuming, stop vacuuming and check for air leakage.
If the pressure reaches 14.6 psi 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 7.25 psi (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.
Low pressure
gauge
Connected to indoor unit
Ball valve fully closed
Main piping
(gas side)
Header outdoor unit
Service port
Brazed
Brazed
Service port
Packed valve fully closed
(liquid side)
Follower units
High pressure
gauge
Gauge
V
V
L
H
manifold
P
Vacuum pump
30-EN
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