Valterra

Valterra unions and PVC plumbing fittings for pools

Valterra is a familiar name in PVC plumbing for pools, spas and water treatment, where its valves, unions and adaptors are used to join pipework and to make pumps, filters and heaters removable for service. Here you will find the Valterra parts carried for pool circuits, built around three-part union connections that let a piece of equipment be taken out of the line without cutting pipe. The current listing covers the 3-part union 63 mm female to 2-inch MPT, reference SBM363G.

Metric pipe on one side, imperial thread on the other

Pool installations across Europe mix two worlds. Pipe and solvent-weld fittings are usually metric — 50 mm, 63 mm, 75 mm — while many pumps, filters, heat exchangers and chlorinators arrive with imperial threaded ports stated in inches. A union that is metric on one end and threaded in inches on the other removes the need for a stack of adaptors at the equipment.

The SBM363G does exactly that. One side accepts 63 mm pipe, the other is a 2-inch male pipe thread (MPT) that screws into a female port on a pump, filter or manifold. The result is a single joint where there would otherwise be two or three, which means fewer places to leak and a shorter run of fittings in a tight equipment bay.

What a three-part union does

A three-part union is made up of a tail that bonds or threads to the pipe, a second tail on the equipment side, and a nut that draws the two together onto a seal. Because the nut unscrews, the equipment can be lifted out while both halves of the pipework stay where they are. On a pool circuit that matters every time a pump is stripped, a filter is moved, or a heater is winterised.

• Pump connections — unions on the suction and discharge sides allow the pump to be removed for seal or impeller work without disturbing the manifold.
• Filter inlet and outlet — makes it possible to swing a multiport valve or open a tank for media changes.
• Heaters and heat pumps — allows the unit to be isolated and drained at the end of the season.
• Salt chlorinators and dosing lines — the cell or injection point can be taken out for cleaning and refitted on the same seal.
• Service points on long runs — a union near a buried line gives a clean break point for future work.

Choosing and measuring before ordering

Union sizing trips people up because the two ends are described in different systems. Check each side separately rather than assuming the fitting is “2 inch” throughout.

• Pipe side — measure the outside diameter of the existing pipe. A 63 mm union takes pipe with a 63 mm outside diameter; 50 mm pipe will not fill the socket and must not be shimmed.
• Threaded side — confirm the equipment port is a 2-inch female thread and check the thread form against the port before buying, as imperial tapered and parallel threads are not interchangeable.
• Male or female — note which half of the joint carries the thread, so the new fitting mates with what is already on the equipment.
• Space around the nut — a union nut needs clearance to turn. Measure the gap between the port and the nearest wall, tank or valve body.
• Seal condition — if an older union is weeping, measure the existing O-ring before deciding whether a seal or the whole fitting is required.

Installation and maintenance notes

Union nuts are designed to be tightened by hand against the O-ring; excess force with a strap wrench can distort the seal or crack the nut, and it does not improve the joint. Thread sealant or PTFE tape belongs only on the tapered male thread going into the equipment, never on the O-ring face, where it prevents the seal seating evenly.

Solvent-weld sockets should be clean, dry and free of grit before cement is applied, and the joint left to cure before the system is pressurised. During winterising, slackening union nuts helps drain the equipment and takes the load off the seals. An O-ring that has gone flat, hard or shiny is the usual cause of a slow drip at a union and is worth inspecting whenever a pump or filter is opened.

Valterra at PoolParthub.com

Here we list the Valterra plumbing parts we keep for pool circuits, including the 3-part union 63 mm female to 2-inch MPT (SBM363G) that bridges metric pipe and imperial equipment ports. It is stocked because that transition appears on almost every installation where European pipework meets an imported pump, filter or heater.

Unions are the parts that make a pool serviceable, so they are worth having on the shelf alongside seals and O-rings. If you are unsure which half of a joint you need, measure the pipe outside diameter and the equipment port thread and compare both with the description above before ordering.