# Boiler and OPV thread?



## Daniel R (Feb 2, 2020)

Hi,

I'm trying to understand the thread on the boiler etc (post 2008).

The 1/8 BSP has two types:



BSPP - parallel (straight)


BSPT - tapered


To get a tight fit it's common the have a tapered male into straight female. So my guess is:



Boiler water inlet (side): female BSPP


Boiler steam (top): male BSPT


Pump hose: male BSPT


Can anyone confirm or correct?

Daniel


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## El carajillo (Mar 16, 2013)

I think you will find taper threads and parallel threads do not mix. A taper thread will only contact correctly at one point in a parallel thread giving an insecure joint.

Use PTFE on threads to form secure leak free joints.


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## Daniel R (Feb 2, 2020)

Have a look at

https://en.wikipedia.org/wiki/British_Standard_Pipe

under the heading "Jointing threads"


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## Daniel R (Feb 2, 2020)

El carajillo said:


> I think you will find taper threads and parallel threads do not mix. A taper thread will only contact correctly at one point in a parallel thread giving an insecure joint.
> 
> Use PTFE on threads to form secure leak free joints.


 So, you are saying it all BSPP?


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## El carajillo (Mar 16, 2013)

Generally the threads are parallel as most European water fittings. The fitting on the end of a pipe can be an OLIVE, a cone shaped nipple or a flat end to receive a flat seal (eg washing machine hose ) The thread will be parallel. Hope this helps.


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