Air Valves: Supply & Extract

Frequently asked questions

What is the difference between a supply and an extract air valve?

A supply valve has a shaped centre disc that spreads incoming air across the ceiling so it mixes into the room without a draught. An extract valve has a profile that draws air in evenly from around the valve. They are not interchangeable: an extract valve used on a supply duct throws the air straight down. Some plastic valves are designed for either duty and say so in the title.

Metal or plastic air valve?

Metal valves are galvanised or powder coated steel, robust and the usual choice for MVHR and commercial systems. Our white plastic valves are polypropylene, heat resistant to 100°C, and suit humid rooms such as kitchens and bathrooms. Both adjust in the same way.

How do I adjust an air valve?

Rotate the centre disc to open or close the gap, which sets the airflow at that valve. On a system with several valves, each one is set during commissioning so every room gets its design airflow, then locked so it stays balanced. Avoid changing settings afterwards, because it upsets the rest of the system.

How are air valves fitted?

Most fit into a mounting ring or frame fixed to the duct or ceiling, with a quarter turn or spring fixing, so the valve can be pulled out for cleaning without disturbing the duct. Match the valve size to the duct diameter.

Do I need a fire rated air valve?

If the duct passes through a fire compartment ceiling or wall, the fire strategy may call for a fire damper at that point. We stock an air valve with a built-in fire damper for exhaust systems.

How do I clean an air valve?

Pull the valve out of its ring, wash it in warm soapy water, dry it and push it back in. Take care not to turn the centre disc, or mark its position first, so the airflow setting is not lost.