Daikin VRV III RXYQ5-54PY1 Service Manual page 159

Test Operation
1.2.3.2 Air Tight Test and Vacuum Drying Method
After finished piping work, carry out air tight test and vacuum drying.
<Air tight test>
Pressurize the liquid and gas pipes to 4.0MPa (40bar) (do not pressurize more than 4.0MPa
(40bar)). If the pressure does not drop within 24 hours, the system passes the test.
If there is a pressure drop, check for leaks, make repairs, and perform the airtight test again.
<Vacuum drying>
Evacuate the system from the liquid and gas pipes by using a vacuum pump for more than 2
hours and bring the system to –100.7kPa or less. After keeping the system under that condition
for more than 1 hour, check if the vacuum gauge rises or not. If it rises, the system may either
contain moisture inside or have leaks.
Note:
1. After performing the vacuum drying for two hours, pressurize to 0.05 MPa (i.e., vacuum
2. If the pressure does not reach –100.7 kPa even after depressurizing for at least two hours,
After vacuum drying, maintain the vacuum for an hour and make sure the pressure does not rise
by monitoring with a vacuum gauge.
1.2.4 Additional Refrigerant Charge and Check Operation
The outdoor unit is charged with refrigerant when shipped from the factory, but depending on
the size and length of the piping when installed, it may require additional charging.
For charging the additional refrigerant, follow the procedure in this chapter.
And then carry out the check operation.
Note: Total amount of refrigerant should be 100 kg or less
1.2.4.1 Before Working
[About the refrigerant cylinder]
Check whether the cylinder has a siphon pipe before charging and place the cylinder so that the
refrigerant is charged in liquid form. (See the figure below.)
With siphon pipe
Other tanks
Caution
148
If moisture might enter the piping, follow belows.
(I.e., if doing work during the rainy season, if the actual work takes long enough that
condensation may form on the inside of the pipes, if rain might enter the pipes during
work, etc.)
breakdown) with nitrogen gas, then depressurize down to –100.7 kPa for an hour using the
vacuum pump (vacuum drying).
repeat the vacuum breakdown - vacuum drying process.
Always use the proper refrigerant (R-410A). If charged with the refrigerant containing an
improper material, it may cause an explosion or accident.
R-410A is a mixed refrigerant, so charging it as a gas will cause the refrigerant composition
to change, which may prevent normal operation.
Stand the cylinder upright and charge.
(The siphon pipe goes all the way inside,
so the cylinder does not need be put
upside-down charge in liquid form.)
Stand the cylinder upside-down and charge.
Si34-601A
Test Operation