Double union ball valves have both advantages and disadvantages – figuring out where you need the valve in your pipe system and what kind of control you want to have over the flow will help you decide whether a double union ball valve is the right choice for you.

A PVC gate valve is quite a complex valve compared to more simple valves, like a ball valve, but is fantastic for fine control of flow. The wheel at the top of the valve has about eight/eight-and-a-half turns from fully shut to fully open, which allows for very small movements in the internal workings of the valve. This gives you fine control of your flow.

We are regularly asked what is the best way to connect metal threads to plastic threads.

There are two main options. Firstly, using a standard threaded fitting and a metal thread, just to thread it straight on. The second option would be to use some special fittings, which are composite unions. With a composite union, there is metal on one side and a plastic socket on the other.

PVC ventilation systems can be joined by either solvent weld, hot air welding, or using a temporary sealer such as silicone / mastic. PPS system can only be hot air welded.