Air in Hydronics

  March 1, 2014      Jeff Rosenblum


When working with a hydronic system the biggest enemy is air. An air bubble can reduce the amount of water in the pipe and therefore the pipe cannot carry as much heat. When we displace the water we are limiting the amount of BTU’s the pipe can carry. Let’s say a 3/4” baseboard is putting out 550 BTUH at 180-degree water. Now, displace half of that water with air. Your baseboard is now only delivering 275 BTUH. That is a huge difference! There is no place for air in the hydronic system. The more air, the less efficient. Water boilers should be equipped with an air removal device to automatically remove the air. Now that we have covered the piping side, let’s discuss the pump side. A boiler’s pump can only pump water. If we try to pump air the pump will cavitate. This means the pump just spins and does not move the water. Boiler pumps can also be called circulators. Their job is to circulate the water through the system, if air is in the impeller, the pump will not effectively move the water.

Jeff Rosenblum 
Technical Support
15 Years Industry Experience
Cell (330) 962-2491