The air-admittance valve is probably best compared to a larger version of the non-return type of valve in which the air is fed into your system through the valve but will not allow bad smelling air to escape into the atmosphere local to your WC. This valve is a very efficient alternative valve which can take the place of your original siphon type, which is the most common types fitted in a WC system. So if a negative pressure is in the drain of the system, the valve will open rather than the trap water being dragged out. Brockley Plumbers can fit all types of valves for plumbing systems including the air admittance valve.

The air admittance valve can be purchased from most plumbing merchants and are made and supplied in quite a range of sizes and sometimes the main waste drainage stack can be fitted with this type of valve. These valves are normally used when two soil stacks are in the same building, or where there are a few buildings that are situated close to each other.

Fitting this type of valve means there is no requirement to route the highest point of the soil discharge stack out through the roof. This means that there is no real requirement for any extra work like tiling for example, and it will also protect the building from rainwater entering. The air admittance valve works best when it is installed above the critical level for any spillages of an appliance. If the valve is not fitted in that position and a blockage happens it would back up and cause the valve to lose its watertight integrity. A Brockley Plumber is familiar with this system. Provided that this valve is well insulated it can be fitted in any exposed location such as, a loft space, as condensation in the pipes can freeze.