The non-return valve is a system designed to control the direction of flow of a fluid in one direction. Most of the time, these are anti-pollution valves which prevent impurities from going up in the system, by preventing for example that the waste water does not contaminate the water intended for consumption. This is valid inside a dwelling but also in the water distribution circuit in general. The health rules to be observed in this area are very strict. Not all non-return valves are certified anti-pollution. The latter must equip any individual accommodation for domestic hot water.
The advantages of the non-return valve
To be effective, the non-return valve is systematically installed after the water meter. Some facilities, such as hot water tanks, already have them. But in older installations, this is not always the case. It is therefore advisable to choose an NF certified model so that your installation meets the standards in force. The non-return valve is also highly recommended if you have a toilet with a grinder to avoid any risk of backflow. The PVC valve is then simply glued to the drain pipe. Equipped with a twist-off cover, it also allows easy access to the pipe and unblock it if necessary.
Non-return valve: watch out for "water hammer"
Certain models of valves which abruptly close can cause a phenomenon of "water hammer" (noise and blows in the pipes due to a rapid drop in pressure). This is also the case with many household appliances that have them. If this is the case, you will also need to install a water hammer to counter this inconvenience.