Adjustable Radiator Union Tail 1/2 inch

Fitted into the 1/2″ tapping of a rad, the adjustable radiator union tail lets the valve reach further. When a replacement radiator is slightly narrower than the old one, it can save you moving the pipes.

Choosing an adjustable radiator union tail

Two versions are sold: one with a 20mm tail and one with a 40mm tail. Measure the gap between the old pipe centres and the new radiator tappings, then choose the tail that covers it. The extra reach lets the existing valves line up without cutting and bending the pipework.

Wrap the thread with PTFE or use a suitable sealant, and screw the tail into the radiator. Use a proper radiator spanner rather than grips so you do not damage the finish. Hang the rad, then connect the valve union nuts.

Once the system is filled, check both joints closely as it warms up. Bleed the radiator and top up the pressure on a sealed system.

More radiator parts are in our Flexible range.

Union tails at the Glasgow counter

At Plumb Parts, 555 South Street, Glasgow G14 0QX the counter keeps Mon-Fri 8am-5pm and Sat-Sun 8am-1pm hours. Online works too.

Specification

• Connection: 1/2″ thread into the radiator tapping
• Sizes: 1/2″ with a 20mm or 40mm tail
• Suitable for: Radiator swaps where the new tappings do not meet the old valves

Common Questions

Which tail length do I need?

Measure the gap between the new radiator tapping and where the existing valve sits. Pick the 20mm tail for a small gap and the 40mm one when the shortfall is bigger.

How do I seal the thread into the radiator?

Wrap PTFE tape round the thread or use a suitable jointing paste, then tighten with a radiator spanner. Avoid grips, which chew the hex and mark the finish.

Will it fit any radiator?

It suits radiators with a 1/2″ tapping, which most panel radiators have. Check yours before ordering, as some older or designer radiators use other sizes.