Gas Fitter Practice Test

What should be done to prevent air entry during the temporary shutdown of a hydronic system?

1. Close the main valves

2. Utilize a backflow preventer

3. Drain the system completely

4. Maintain pressure in the system

The correct answer is: Maintain pressure in the system

Maintaining pressure in the hydronic system during a temporary shutdown is essential to prevent air from entering the system. When the system is under pressure, it creates a barrier that helps keep air from infiltrating through any potential leaks or openings. Air entry can lead to a range of issues in hydronic systems, such as reduced efficiency, noise, and the potential for corrosion or damage to components. While closing the main valves might seem beneficial, it wouldn’t necessarily prevent air from entering the system if there are other points of potential air entry. A backflow preventer is more related to preventing contaminated water from entering the potable water supply, rather than dealing with air entry in hydronic systems. Draining the system completely would not be advisable as it inherently allows air to enter and could cause significant problems when attempting to refill and restore the system to operational status. Therefore, maintaining pressure ensures that the system remains intact and free from air intrusion, promoting optimal performance and longevity of the system upon restarting.