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rise a bit, but MUST eventually stop rising for fifteen
(15) minutes.
•
If the micron level DOES NOT stop rising, there is
a leak, and the leak test must be performed again.
•
If the micron level DOES rise above 2,000 micron,
re-open the manifold gauges and the vacuum
pump valve and continue evacuation back down to
2,000 micron level.
•
If the micron level holds at 2,000 micron, continue
to step 4.
4. Break vacuum with 50 psig nitrogen purge for an
appropriate amount of time (this is to "sweep"
moisture from piping).
5. Purge nitrogen from the system until the pressure
drops down to 1 to 3 psig.
6. Evacuate to 1,000 micron level. Isolate the pump by
closing the manifold gauges and the vacuum pump
valve, and then watch the micron level. Micron level
could rise a bit, but MUST eventually stop rising for
fifteen (15) minutes.
•
If the micron level DOES NOT stop rising, there is
a leak, and the leak test must be performed again.
•
If the micron level DOES rise above 1,000 micron,
re-open the manifold gauges and the vacuum
pump valve, and continue evacuation back down to
1,000 micron level.
Figure 33: Evacuation Diagram for Heat Recovery Systems
Note:
Farthest slave outdoor unit is the slave outdoor unit installed farthest away from the refrigerant piping system / RTU unit
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Due to our policy of continuous product innovation, some specifications may change without notification.
•
If the micron level holds at 1,000 micron, continue
to step 7.
7. Break vacuum with 50 psig nitrogen purge for an
appropriate amount of time
8. Purge nitrogen from the system until the pressure
drops down to 1 to 3 psig.
9. Evacuate to static micron level ≤ 500
10. Micron level must remain ≤ 500 for 24 hours. If the
vacuum gauge rises and stops, the system could
contain moisture, therefore, it will be necessary to
repeat the steps of vacuum break and drying.
11. After maintaining the system in vacuum for 24
hours, check if the vacuum gauge rises or not. If it
doesn't rise, then the system is properly evacuated.
12. Close manifold gauges.
13. Shut the valve before turning off the vacuum pump.
Note:
If the outdoor unit is moved to and installed in another site,
only charge with new refrigerant after successful leak test and
triple evacuation procedures have been performed. If different
refrigerant or air is mixed with the original refrigerant, the
refrigerant cycle will malfunction and the unit will be damaged.
37
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