Which plan is correct for charging 600 pounds of R-123 into an evacuated centrifugal chiller?
Recharging techniques · EPA 608 Type III. The correct answer, and the reasoning behind it.
Charging vapor before liquid, and charging centrifugals through the evaporator valve.
The question
Which plan is correct for charging 600 pounds of R-123 into an evacuated centrifugal chiller?
- Charge vapor, then liquid, through the evaporator charging valve with water flowingCorrect answer
- Charge liquid, then vapor, through the condenser relief connection with the pumps off
- Charge liquid only, through the purge unit, with water drained
- Charge vapor only, through the compressor discharge, with pumps off
Why “Charge vapor, then liquid, through the evaporator charging valve with water flowing” is correct
EPA's test topics combine two charging points for centrifugals: introduce vapor before liquid to keep tube water from freezing, and charge through the evaporator charging valve. Keeping water circulating adds another layer of protection.
Source: EPA: Test Topics
Why the other answers are wrong
- Charge liquid, then vapor, through the condenser relief connection with the pumps off — Liquid first risks freezing, and still water in the tubes makes it worse.
- Charge liquid only, through the purge unit, with water drained — The purge unit is not a charging point, and liquid first risks freezing.
- Charge vapor only, through the compressor discharge, with pumps off — Centrifugals are charged through the evaporator charging valve, not the discharge.
Practice more of this
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