Vacuum Breaker Test Equipment

Sight Tube

• Sight tubes are the primary piece of equipment for testing vacuum breakers. Sight tubes contain water and a small ball or other float inside the tube. The sight valve is connected to the lower of the two testcocks. When water runs through the pressure breaker, the float within the sight tube will rise or fall depending on the pressure inside the device. Most sight tubes contain graduated marks that show the exact level of pressure.

Ball Valves

• All pressure vacuum breakers contain two ball valves. These valves control the flow of water inside the breaker. When testing a vacuum breaker or performing maintenance, the ball valves act as a shutoff. Turning both of the valve handles 90 degrees clockwise will shut off the flow of water. During winterization, it's important to leave the valve handles at a 45-degree angle so that any trapped water has room to expand inside the pipes. Valve handles can also be turned slightly to reduce water pressure during sight tube tests.

Testcocks

• Most pressure vacuum breakers contain two small valves on the side called testcocks. These valves serve a variety of purposes. Turning the valve with a screwdriver will test whether the system is charged under pressure. Water will spray from a charged testcock. Opening a testcock during the winter will also help drain the vacuum breaker. The lower of the two testcocks also is a connection point for a sight tube test kit, which measures the performance of the breaker.

Poppet and Bonnet

• The poppet and bonnet are both plastic pieces that fit inside the vacuum breaker. These devices help maintain the vacuum seal within the breaker during normal operation. The poppet and bonnet also act as test equipment, as they are designed to break if there is a problem with the vacuum breaker. Open the lid and pull out the poppet and bonnet. Inspect both pieces for signs of cracks or breaks in the plastic fins. The plastic is designed to break as a safety measure if either piece fails and the vacuum inside the device is broken.