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11. Air-tightness test.
For the final check, there should be no pressure drop when
3.3 MPa is applied for 24 hours.
12. Vacuum drying.
Vacuum draw time
* Vacuum pump capacity 60 l/min. or higher
• • • • Drawing the vacuum will remove any moisture.
• • • • The pressure after vacuum drawing should be 755
mmHg or less.
• • • • Use a special vacuum pump (with backflow-prevention
mechanism).
• • • • Gas must never be used for air purging.
13. Additional refrigerant charging.
• • • • Check that refrigerant volume is correct.
• • • • Be sure to charge refrigerant in liquid state.
• • • • Always charge in liquid state.
When the refrigerant is charged from the cylinder, the
composition may change greatly (compounds which do
not easily evaporate may remain inside the cylinder), so
the refrigerant must always be charged in a liquid state.
60 min. or more
8
(It is recommended that a manifold with sight glass be
used.)
Boiling point at normal atmospheric pressure
(reference)
Refrigerant
HFC32
Boiling point
-52°C
• • • • Use a special gauge manifold and charging hose.
• • • • If refrigerant leaks occur, replace all of the refrigerant
(same as for R22).
• • • • Note that a R22 leak detector cannot be use to detect
leaks.
• • • • Refer to the Installation Instructions included for the
correct charging amount.
• • • • Make a note of additional refrigerant charging amounts
in the record table.
14. Test operation and adjustment.
15. Organize documentation before handover.
16. Handover and explanation of operation.
• • • • Ventilation of closed rooms
R407C is a non-flammable refrigerant with low toxicity,
but in the gas state its specific gravity is heavier than
that of air, and so if leaks occur in a closed room,
suffocation may occur. Toxic gases may also be
generated if it comes into direct contact with flames, so
adequate ventilation must be provided.
HFC125
HFC134a
-49°C
-26°C
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