Vacuum Process; Additional Charging - Fujitsu AJ*A72LALH Series Installation Manual

8. 2.

Vacuum process

• Do not turn on the power unless all operations are complete.
• If the system is not evacuated suffi ciently, its performance will drop.
• If moisture might enter the piping, follow below. (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.)
• After operating the vacuum pump for 2 hours, pressurize to 0.05 MPa (i.e., vacuum breakdown) with nitrogen
gas, then depressurize down to -100.7kPa (-755mmHg) for an hour using the vacuum pump (vacuum process).
• If the pressure does not reach -100.7kPa (-755mmHg) even after depressurizing for at least 2 hours, repeat the
vacuum breakdown - vacuum process.
After vacuum process, maintain the vacuum for an hour and make sure the pressure does not rise by monitoring
with a vacuum pauge.
Evacuation procedure
1) Remove the caps of the gas pipe and liquid pipe and check that the valves are closed.
2) Remove the charging cap.
3) Connect a vacuum pump and a pressure gauge to a charging hose and connect it to the charging port.
4) Activate the vacuum pump and vacuum the indoor unit and connection piping until the pressure gauge be-
comes -100.7kPa (-755mmHg).
Evacuate from both the gas pipe and the liquid pipe.
5) Continue evacuating the system for 1 hour after the pressure gauge reads -100.7kPa (-755mmHg).
6) Remove the charging hose and reinstall the charging cap.
8. 3.

Additional charging

• Do not turn on the power unless all operations are complete.
• After evacuating the system, add refrigerant.
• Do not charge the system with a refrigerant other than R410A.
• Always keep to the limit on the total amount of refrigerant. Exceeding the limit on the total amount of refrigerant
will lead to malfunction during charging of refrigerant.
• Do not reuse recovered refrigerant.
• Use an electronic scale to measure the charging amount of refrigerant.
Adding more refrigerant than the specifi ed amount will cause a malfunction.
• Charge refrigerant using the liquid pipe.
Adding refrigerant through the gas pipe will cause a malfunction.
• Add refrigerant by charging the system with the refrigerant in the liquid state. If the refrigerant cylinder is
equipped with a siphon, it is not necessary to place the cylinder upright.
8. 3. 1. Procedure for charging the system with refrigerant
1) Remov e the charging cap from the liquid pipe.
2) Attach a charging hose to the refrigerant cylinder, and connect it to the charging port.
3) Add refrigerant by calculating the additional refrigerant volume in accordance with the calculation formula
indicated below.
4) Remove the charging hose and install the charging cap.
5) Remove the body caps (gas pipe, liquid pipe, and oil pipe {if multiple units are installed}), and open the
valves.
6) Close the body caps.
7) After a dding refrigerant, indicate the added charging volume on the unit.
* Tighten the body caps and charging caps to the torque values specifi ed in the Table A.
To open and close the valves,
Use an M4 hexagon wrench for liquid and oil pipes.
Use an M10 hexagon wrench for gas pipes.
* *
If you can not charge the specifi ed amount of refrigerant with the above method, be sure to charge the refrigerant through the gas pipe
while operating in cooling mode. In order to prevent liquid back-fl ow, carefully operate the cooling cylinder valve so that the refrigerant will
fl ow in certain part at a time.
CAUTION
CAUTION
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