21
ENGLISH
37
(4)
Do a leak test of all joints of the tubing (both indoor and
outdoor) and both gas and liquid service valves. Bubbles
indicate a leak. Wipe off the soap with a clean cloth after a
leak test.
(5)
After the system is found to be free of leaks, relieve the
nitrogen pressure by loosening the charge hose connector
at the nitrogen cylinder. When the system pressure is
reduced to normal, disconnect the hose from the cylinder.
Evacuation
(1)
Attach the charge hose end described in the preceding
steps to the vacuum pump to evacuate the tubing and
indoor unit. Confirm that the “Lo” knob of the manifold valve
is open. Then, run the vacuum pump. The operation time
for evacuation varies with the tubing length and capacity of
the pump. The following table shows the amount of time for
evacuation:
Required time for evacuation
when 30 gal/min. vacuum pump is used
If tubing length is
less than 15 m
If tubing length is
longer than 15 m
45 min. or more
90 min. or more
NOTE
The required time in the above table is calculated based on the
assumption that the ideal (or target) vacuum condition is less
than –101 kPa {–755 mmHg, 5 Torr}.
(2)
When the desired vacuum is reached, close the “Lo”
knob of the manifold valve and turn off the vacuum pump.
Please confirm that the gauge pressure is under –101 kPa
{–755 mmHg, 5 Torr} after 4 to 5 minutes of vacuum pump
operation.
Lo
Hi
Manifold valve
Vacuum pump
Outdoor unit
Vacuum gauge
Close
Close
Open
Open
Gas tube
Liquid tube
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38
CAUTION
Use a cylinder designed for use with
R410A respectively.
Charging additional refrigerant
●
Charging additional refrigerant (calculated from the liquid
tube length as shown in the section “1-8. Additional
Refrigerant Charge”) using the liquid tube service valve.
●
Use a balance to measure the refrigerant accurately.
●
If the additional refrigerant charge amount cannot be
charged at once, charge the remaining refrigerant in liquid
form by using the gas tube service valve with the system in
cooling operation mode at the time of test run.
Finishing the job
(1)
With a hex wrench, turn the liquid tube service valve stem
counter-clockwise to fully open the valve.
(2)
Turn the gas tube service valve stem counter-clockwise to
fully open the valve.
CAUTION
To avoid gas from leaking when
removing the charge hose, make sure
the stem of the gas tube is turned all the
way out (“BACK SEAT” position).
(3)
Loosen the charge hose connected to the gas tube service
port (1/4 in.) slightly to release the pressure, then remove
the hose.
(4)
Replace the 1/4 in. flare nut and its bonnet on the gas
tube service port and fasten the flare nut securely with an
adjustable wrench or box wrench. This process is very
important to prevent gas from leaking from the system.
(5)
Replace the valve caps at both gas and liquid service valves
and fasten them securely.
This completes air purging with a vacuum pump. The air
conditioner is now ready for a test run.
Lo
Hi
R410A
Manifold valve
Pressure gauge
Liquid
Valve
Close
Close
Close
Close
Open
Open
Open
Open
Liquid tube
Outdoor unit
Outdoor unit
Gas tube
Liquid tube
Gas tube
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00̲280434̲Mini̲VRF̲Mentsuke.indb 21
00̲280434̲Mini̲VRF̲Mentsuke.indb 21
2016/06/16 11:37:43
2016/06/16 11:37:43
