Patrick Gordon of Calafrica (

Q – How does an Automatic Air Release Valve work?

During the daily use of our plumbing systems air can be trapped in various places. Normally air percolates to the highest places in the pipe system. When we use our taps, we will notice the presence of air in the system by a spluttering when the taps/mixers are used. This can be very annoying. By fitting an Air Release Valve this phenomenon can be prevented without us having to do anything extra.

Automatic Air Release Valve

Automatic Air Release Valve

So how does it work?

The valve must be installed in a vertical position at the highest point of that part of the system. The valve consists of a chamber that contains a float (1) attached to a needle valve (2). The weight of the float would normally keep the needle valve in the open position. Because air is lighter than water the air will go to the highest point, where the valve is fitted, and escape via the open needle valve. As the air escapes the water level in the system will rise and start to fill the chamber of the Air Release Valve. Because the float is buoyant the water will lift it and cause the needle valve to close. When this happens the seal on the needle valve seat is forced closed and will prevent the water from escaping. If any other air finds its way to the top of that part of the plumbing system, the float will again open the needle valve and allow the air to escape.
Installations like solar heating systems are more prone to trapping air. For installations like that, the heat factor must be considered and a valve with a suitable temperature rating should be selected.

Patrick GordonFor any further information regarding this topic please feel free to contact Patrick Gordon on +27 (0)83 303 1437.

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