EPA 608 Type III · Recharging Techniques · Medium
Why is a low-pressure chiller introduced with refrigerant vapor before liquid refrigerant during the charging process?
Answer: C. To keep the water in the tubes from freezing
- ATo prevent liquid slugging in the compressor
- BTo avoid fractionating the zeotropic blend
- CTo keep the water in the tubes from freezing✓ Correct
- DTo purge non-condensables from the system
Why C is right
In a deep vacuum, liquid refrigerant entering the system would boil at a very low temperature, potentially freezing the water in the tubes and rupturing them. Vapor is charged first until the pressure is above the saturation pressure that matches 32°F, the freezing point of water.
More Type III questions
- Before charging liquid into a chiller, what must the system pressure be?
- Why must low-pressure chillers be designed to be completely airtight?
- R-123 is rated B1 under ASHRAE 34. What does that mean?
- Which HCFO refrigerant is replacing R-123 in new low-pressure chillers?
- A chiller with a 1,000-lb full charge needs 50 lbs added, 73 days after the last addition. What is its annualized leak rate?
Go deeper with the study guide A2L Refrigerants and the R-410A Transition: A Tech’s Guide, try the free 10-question test or browse all EPA 608 practice questions.
A practice question written for study, checked against 40 CFR Part 82, Subpart F. It is not an official EPA exam question, and this site is not affiliated with the U.S. EPA.