TRVs

[NozSpark]

How can I tell if the valves have 3/4 or 1/2 tails? I mean from item desctiption. In the SF lists they all look like 1/2 if you compare the rad coupling with the pipe entry?

Tape measure?: ROTFWL

 

[Sidewinder]

Rev,

Rad valves will almost certainly be 1/2" BSP if they are 15mm entry the sizes are about the same, in fact IIRC the thread used on a 15mm compression nut is 1/2" BSPP.

I am unloading plumbing stuff in the morning, I'll try to remember to check!

 

[steptoe]

SW, you are correct on the 15mm vs 1/2" thread issue,

AFAIK its just the bore that differs slightly.

 

[Sidewinder]

Metric pipes are characterised & measured by OD.

Imperial pipe sizes are characterised & measured by bore.

Well at least in the UK they are!

Metric ones are OD globally, but not sure about the global imperial pipe standards, though NPT is bore.

 

[revjames]

The nut which connects the valve to rad is considerably bigger in diameter than the nut on the pipe fitting (15mm) thats why I'm confused

 

[Sidewinder]

Rev,

Some old fittings had a 1/2" BSP M for the rad end, and a 3/4" BSP loose nut for the valve IIRC.

Don't think I have any of these still kicking around.