Hitachi AirCore 700 Installation & Maintenance Manual page 20

4. Installation Instructions
Fix the end of piping tape with adhesive tape.
When piping has to be arranged through above ceiling,
closet or area where temperature and humidity are high,
use wind additional commercially sold insulation for
prevention of condensation.
5. Air tight test
•
Do use Nitrogen
•
Connect the gauge manifold using charging hoses
with a nitrogen cylinder to check joints of the liquid
line and the gas line stop valves.
•
Perform the air tight test.
•
Don't open the gas line stop valves.
•
Apply nitrogen gas pressure of 4.15MPa.
•
Check any gas leakage at flare nut connections, or brazed parts by gas leak detector or foaming agent.
•
It is OK if gas pressure doesn't decrease.
•
After the air tight test, release nitrogen gas.
6. Vacuum pumping and charge refrigerant
•
Vacuum pumping
(1) Remove the service port cap of the stop valve on the gas pipe side of the outdoor unit.
(2) Connect the manifold gauge and vacuum pump to the service port of the stop valve on the gas pipe
side of the outdoor unit.
(3) Run the vacuum pump. (Work for more than 15 minutes.)
(4) Check the vacuum with the gauge manifold valve, then close
the gauge manifold valve and stop the vacuum pump.
(5) Leave it as is for one or two minutes. Make sure that the
pointer of the manifold gauge remains in the same position.
Confirm that the pressure gauge shows -0.101MPa (or
-760mmHg).
(6) Remove the manifold gauge quickly from the service port of
the stop valve.
(7) After refrigerant pipes are connected and evacuated, fully
open all stop valves on both sides of gas pipe and liquid pipe.
(8) Tighten the cap to the service port.
(9) Retighten the cap.
(10) Leak test foam with halogen leak detector to check the flare
nut and brazing leaks. Use foam that does not generate
ammonia (NH ) in the reaction.
3
CAUTION
!
•
An excess or a shortage of refrigerant is the main cause of trouble to the unit. Charge the correct
quantity of refrigerant according to the description in the manual.
Check refrigerant leakage in detail. If a large refrigerant leakage occurs, it will cause difficulty in
breathing or harmful gas will occur if a fire is being used in the room.
Clamp
Procedure
Connect
refrigerant pipe Nitrogen Gas
F i g.9. 2
Pressure gauge
Manifold
valve
-16-
Tightening torque for
Insulation
Refrigerant pipe
Insulation
Piping insulation procedure
Check of pressure
Fill
Decrease
Repairing of
Leakage part
Indoor unit
Outdoor unit
Charge hose
(for R32)
Vacuum pump
nut
Pass