While charging R-123 into a chiller that was evacuated, what should be done with the water in the tubes?

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

While charging R-123 into a chiller that was evacuated, what should be done with the water in the tubes?

• AStop the pumps to lower the heat load
• BClose the valves to trap water in the tubes
• CLeave it alone; charging cannot cause freezing
• DKeep it circulating, or drain itCorrect answer

Why “Keep it circulating, or drain it” is correct

The same freezing risk that exists during evacuation exists during charging, until the pressure is above the 32 °F saturation point. Keeping water moving through the tubes, or draining them, protects the tubes.

Source: EPA: Test Topics

Why the other answers are wrong

• Stop the pumps to lower the heat load — Still water in the tubes is what is at risk of freezing.
• Close the valves to trap water in the tubes — Trapped, still water can freeze and burst the tubes.
• Leave it alone; charging cannot cause freezing — Charging into a vacuum can freeze the tubes, which is why vapor goes first.

Practice more of this

More EPA 608 Type III practice questions, or see every EPA 608 practice test.