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Vacuum drying pipes and indoor units
Use tools for R-410A to prevent the inflow of foreign substances and resist against the internal pressure.
Use vacuum pump that allows vacuuming under -100.7 kPa (5 Torr).
Use the vacuum pump with the check valve to prevent pump oil from flowing backward while the vacuum pump is
stopped.
Completely close the liquid/gas side service valve of the outdoor unit.
Connect the manifold gauge to the liquid side pipe and
gas side pipe (when installing outdoor units in module).
Perform vacuum drying of the liquid side pipe and gas
side pipe (when installing outdoor units in module) using
a vacuum pump.
While the vacuum gauge pressure is less than -100.7 kPa
(5 Torr), perform the vacuum drying for more than 1 hour
and close the valve.
After vacuum pump stops, check whether the pressure is
maintained within -100.7 kPa (5 Torr) for an hour.
Over -100.7 kPa (5 Torr)
No
Charge additional refrigerant to the pipe
❋ If the pressure rises in an hour, either water is remaining inside the pipe or there is a leakage.
❋ When the ambient temperature of vacuuming pipe is low (less than 0 °C/32 °F), moisture might remain within the pipe.
Therefore, pay special attention to the pipe sealing in the winter.
When installing outdoor units in module, connect the manifold
gauge to liquid side pipe and the gas side pipe.
Make sure that check valve is installed to prevent pump oil from
flowing into the pipe.
Vacuum pressure must be checked with the vacuum gauge.
Check for gas leakage
Yes
Vacuum destruction
Apply nitrogen gas to the pipe at pressure of
0.05 MPa (7.25 psi).
Perform vacuum drying again
No
Pressure increase
ENGLISH-75
Yes
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