Plumbing thread - BSP or not BSP, that is the question

[waddycall]

Did you say you have a nut off another fitting that fits? If so you get another fitting from the same brand it should match.

 

[Jonathan Webb]

Looking at it , you just want 2 nuts and 2 olives from a 22mm compression fitting . Most new cylinders come with them , so you can just pipe up and go ….

As others say they won’t be BSP , but you shouldn’t need any special fittings to make it work . Just the nut and olives .. as most domestic pipe work will be 22mm pipe work unless specified differently .

On the heating coils you should just need some 22mm compression to 3/4 female irons . PTFE up the threads on the cylinder and fit .

Thanks, the coils are 1" BSP & I got the adapter fittings for these. The feed & outlet are smaller so I foolishly assumed they were 3/4"BSP so have 2 fittings to take back...

Compression fittings often have their own threads for joining the 2 parts of the fitting together, Obviously the end thread for connecting to the plumbing is 1/2", 3/4" 1" BSP etc. It was annoying changing a 3 port valve in a cupboard with water dripping out and finding the threads were often finer than the valve you were replacing requiring replacing the old nuts and olives while trying to catch the water. More often than not 1/2" comp fittings also had a 1/2" BSP thread but I have never seen that on any larger fittings.
Most cylinders now come with the compression fittings moulded into the cylinder.

Thanks, I was too focused on the threaded straight adaptor type & didn't clock the olive bevel on the fitting... This cylinder isn't ancient although it has sat around for maybe three years. Mine isn't Gledhill but they state "Standard 1 inch male & female tappings with optional compression fittings available " - so not included on all cylinders and not on this one

 

[MetalMonkey]

IIRC, I think the compression fitting threads on 22mm and over are usually whitworth or possibly metric on newer stuff. 15mm and under should be BSP.
Although I suppose with the cheap stuff around now, it could be anything.

 

[S-Rail]

no problem mate , you aren’t wrong , as 15 is associated with 1/2 inch and 22mm is associated with 3/4 when it comes to compression to a threaded fitting , as others have said , comp nuts can vary . Some are parralel and some are tapered depending on the application.

As for your heating coil being 1” , it could have just been a “special” order or a cylinder knocking about they wanted to move on . It’s no biggy as like you said you’ve adapted down and won’t affect its use .

As you noted , the chamfer on the two fittings is a give away . If you get a newer stainless cylinder , a lot are compression on all 4 points , as they weld a spigot on , which is great from a piping up point of view as it’s one less threaded fitting to leak as the tolerances between manufacturers is appalling . Just take rad valves and radiators , depending on brand , you can be 6 wraps of PTFE up to 16 ….

 

[Morrisman]

We had a wierd one on a ship I worked one once. Compression fitting, male thread, to take a pipe with an olive on, but the thread for tightening down the nut onto was tapered. No idea why, or whether the ‘specialist’ hydraulics company who installed them were a bunch of cowboys.

 

[Kayos]

Thanks, the coils are 1" BSP & I got the adapter fittings for these. The feed & outlet are smaller so I foolishly assumed they were 3/4"BSP so have 2 fittings to take back...

Thanks, I was too focused on the threaded straight adaptor type & didn't clock the olive bevel on the fitting... This cylinder isn't ancient although it has sat around for maybe three years. Mine isn't Gledhill but they state "Standard 1 inch male & female tappings with optional compression fittings available " - so not included on all cylinders and not on this one

The optional compression is an adapter that replaces the olive

I'm amazed, 2 pages and the answer has been given more than once