Solar Air Vent

Removing Air from a Closed Loop Hydronic System such as our Thermax Solar Pool Heater, is often the most challenging part of commissioning the system. When filling a system, water by nature contains micro bubbles of 0xygen that are suspended in the fluid. As the liquid travels through the system both the friction of the piping and the increase in temperature cause these bubbles to become unsuspended and rise to the highest point of the system (often the roof). If not properly removed the build up will cause an annoying “air lock” and result in the pump spinning but no liquid moves.

Solar Air Vents greatly assist in the commissioning task by automatically opening as air accumulates in the vent body. The valve contains a float that is in contact with fluid in the system. The accumulation of air bubbles in the valve body causes the float to drop so that the air vent opens. Once the float drops the air is released out of the valve and the vent shuts off automatically. This ensure that the air is released but never the solar heating fluid.

The solar air vent is placed at the highest point on the solar system which is typically the roof. Often this is also the place most difficult to access. Because the auto features of the vent, installation is a one-time thing with the installer or home owner never having to go back to the roof to manually vent the system.

The inside of an air separator, also called a “microbubble resorber”, is composed of a set of metal screen surfaces arranged like spokes (A). This screen creates a swirling motion to assist the release of microbubbles from the solution and their adhesion to the metal screen. The bubbles join together and increase in size until the hydrostatic force exerted on the air bubble increases to overcome the force of its adhesion to the screen. Next, they rise to the top of the chamber where as the air builds up it displaces the water level and the float starts to drop. In dropping it open a small release port letting the air out of the system and then the chamber is replace with water causing the float to rise and shut back off the vent hole. (B).