EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Medium
A technician is recovering refrigerant from a low-pressure system. To prevent freezing of the water in the chiller barrel during recovery, which of the following measures should be taken?
- AMaintain a continuous flow of water through the chiller barrel.
- BIncrease the flow of refrigerant through the recovery unit.
- CAdd anti-freeze to the chiller water loop.
- DIsolate the chiller barrel from the rest of the system.
Show answer & explanationAnswer & explanation
Correct answer: A. Maintain a continuous flow of water through the chiller barrel.
During refrigerant recovery from a low-pressure chiller, the rapid removal of refrigerant can cause a significant temperature drop in the evaporator (chiller barrel). Maintaining a continuous flow of water through the chiller barrel helps to add heat, preventing the water from freezing and potentially rupturing the tubes.
Why the other options are wrong
- B. Increasing refrigerant flow through the recovery unit would accelerate the temperature drop, increasing the risk of freezing.
- C. Adding anti-freeze is a permanent modification to the system, not a temporary measure for recovery, and typically used for freeze protection in colder climates, not to prevent freezing during active recovery from heat removal.
- D. Isolating the chiller barrel would prevent water circulation, exacerbating the freezing risk.
Low-Pressure Chiller Recovery Safety
A critical safety precaution during refrigerant recovery from low-pressure chillers to prevent the freezing and rupture of water-filled evaporator tubes.
- Rapid refrigerant removal causes temperature drop.
- Chiller barrels contain water.
- Freezing water can rupture tubes.
- Continuous water flow adds heat to prevent freezing.
Memory trick: Recovery cold, water flow, keep it moving, let the heat glow.