HVAC - EPA Certification Practice Exam

What addition helps counteract freezing in systems with excess water?

1. Increase pressure with CO2

2. Increase pressure with nitrogen

3. Use antifreeze solution

4. Reduce refrigerant charge

The correct answer is: Increase pressure with nitrogen

In systems where excess water can lead to freezing issues, the most effective solution is to use an antifreeze solution. Antifreeze solutions lower the freezing point of water, thus preventing the formation of ice inside the system, which could lead to blockages and damage. Increasing pressure with gases like nitrogen or CO2 does not directly address the freezing problem. While increasing pressure might alter the boiling and freezing points slightly, it isn't an effective strategy for dealing with water freezing in HVAC systems. Reducing refrigerant charge does not help prevent freezing and may actually exacerbate issues by reducing system efficiency. Using an antifreeze solution is the standard and reliable method because it specifically targets the freezing issue by modifying the thermal characteristics of the water present in the system, ensuring smooth operation even at lower temperatures.