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.

Spears PVC gate valves are, in our opinion, the best valve for fine control of flow rates.

The handle has to be turned many times between fully closed and fully open states which gives the ability to set very accurate flow rates.

Contractors packs of PVC pipe and fittings.