I am trying to test some radiators for leaks, having had one fail in my daughter's house I thought the tail to valve connection would be
22mm but a normal stop end has a different thread. Can anyone tell me the likely threat size else I will have to replace valves as well as radiator? It measures 30mm across the flats whereas my 22mm stop end is 31mm.AJH
Usually either 1/2 or 3/4" BSP. Readily available at all plumbers merchants, they usually come complete with new valves, so make sure you ask for the right size.
I forget the details, but don't you find two threads of similar diameter but different pitch on radiator valves?
I'll get a 3/4 BSP flanged plug and try it tomorrow
AJH
Radiator connections are taper thread.
I'm pretty sure the cross flats size is an unreliable guide, even ordinary compression fittings do not seem at all consistent in this respect. But the thread on compression fitting nuts is not a standard BSP thread either AFAICS. Nor has the same thread always been used on compression fittings. You many need to replace the fitting that actually screws into the radiator with the one from the new valve, and that is actually a standard BSP taper thread I think.
Yes the standard 22mm compression fitting is not a BSP thread but the radiator tail to the valve is 3/4 BSP. I'm waiting for a 1/2" allen key to take the tail from the radiator then I need to find a 15MM radiator tail with a 3/4" BSP nut and olive which I can cut to length to fit the new radiator. Else I shall make one by extending the old tails.
I'll need to test all the radiators for leaks, I can only assume this one went because of lack of or weak inhibitor but the rest may be on their way out. I'll try and pressurise them with air and see if they blow bubbles with soapy water.
AJH
IIRC the compression fitting for 15 mm pipe on radiator valves is sometimes 3/4 BSP, sometimes not.
The thread on the pipe is BSP. The thread on the nut may or may not be.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.