Non-return valves are one-way valves; which means they allow the the fluid to go only in one direction only; they must therefore be mounted in the way that the arrow on the body is in the same direction as the fluid.
The valves are composed of a spring, a small valve and two brass parts, body and sleeve, which contain them and which are assembled together by means of a thread and sealed using a special thread lock.
To prevent the layer of thread lockers from breaking it is important to avoid twisting moments.
For the installation normal hydraulic practices must be used, and especially:
– For a proper installation of the valve, near curves and circulation pumps, the valve must be mounted at a distance equal to 10 times the diameter of the pipe;
– The installer must be sure that the two pipes are correctly aligned;
– The application of the fixing material (PTFE, hemp) must be limited to the area of the thread, an excess could interfere in the rubber-metal sealing area, compromising the functionality of the valve;
– In the event that the fluid contains impurities (dirt, dust, excessive water hardness) these must be removed or filtered because they could interfere in the rubber-metal sealing area, compromising the functionality of the valve.
HOW TO UNISTALL
To remove the valve from the line or in any case before unscrewing the joints connected to it:
– Wear the protective clothing normally required to work with the fluid contained in the line;
– Depressurize the line;
– During disassembly, apply the key to the end of the valve closest to the pipe.
Check the valve periodically, depending on the use and working conditions, to make sure it is working properly. If there are any leak at the seal, these can be caused by foreign body (dirt, limestone) on the seal. To fix this problem, remove the valve and remove the foreign body using compressed air or tools.