System Heat Pump Outdoor Unit - MegaFrio

Airtight Test and Evacuation
(1) Airtight test
Refrigerant piping installation
Airtight test should be made by pressurizing nitrogen gas to 2.94 MPa. For the test method, refer to the following
figure. (Make a test with the service valves closed. Be also sure to pressurize both liquid pipe and gas pipe.)
The test result can be judged good if the pressure has not been reduced after leaving for about one day after
completion of nitrogen gas pressurization.
Charging
cylinder
Vacuum pump
Indoor unit
(1)
(2) Evacuation
Indoor unit
Check valve
Lo
Lo
Liquid side
Gas side
Liquid side
Gas side
3-Way
valve
3-Way
valve
3-Way
valve
Outdoor unit
Evacuation should be made from the service port provided on the outdoor unit’s service valve to the vacuum
pump commonly used for both liquid pipe and gas pipe. (Make evacuation from both liquid pipe and gas pipe
with the service valve closed.)
* Never perform air purging using refrigerant.
Outdoor unit
• Evacuation should be done for 3 hours or more
after the pressure is under 5 tor.
Scale
Use a gravimeter. (One that can measure down to
0.1 kg.). If you are unable to prepare such a highprecision
gravimeter you may use a charge
cylinder.
Note : Always add an appropriate amount of refrigerant. (For the refrigerant additional charge)
Too much or too little refrigerant will cause trouble.
WARNING
When installing and moving the air conditioner to another site, recharge after perfect evacuation.
- If a different refrigerant or air is mixed with the original refrigerant, the refrigerant cycle may malfunction and
the unit may be damaged.
Installation Manual 31
ENGLISH