BSPT X NPT Adapter:

icesailor

I just installed a Veissmann Vitodens 100 boiler. I used the Veissmann Low Loss Header. It comes with all the fittings to do it. The header comes with a plug in the bottom which comes installed. They give you an adapter to connect into the port where this plug is. The plug seems to be 1/2" but it has an O-ring to seal it.  The adapter is described as a "BSPT X NPT adapter". There is no shoulder for the O-ring. I put 5 wraps of Teflon tape and used Rectorseal #100 Teflon tape on the threads. It leaks even though I cranked on it.

What's the story on "BSPT" threads?

Gordy

British Standard Pipe Thread

www.colder.com/Portals/0/pdfs/NPT.pdf 

STEVE PAUL_3

BSPT fittings

The BSPT designation stands for "British Standard Pipe Thread", and is also referred to as "British Standard Pipe Taper". Both are commonly used. This thread because of it's taper, is similar to the American NSPT pipe thread. Both become pressure tight upon proper torque and thread makeup. A sealing gasket or "O" Ring is not required.

CMadatMe

Loctite

Ice,

Use Loctite or get out some wicking...By the way try Taco's LLH. Makes for an easier install and has better air removal. Also already mounted on strut. Cost is right there with the Viessmann...



http://flopro.taco-hvac.com/products/index.html?current_category=377

EricAune

I 2nd Chris's remedy

Loctite for these threads seems to be the ticket.  I have had similar problems with panel radiators and Loctite (teflon type) has rid all leaks from the start.

icesailor

BSPT X NPT Adapter:

Thanks all. I'll just crank it some more. I have plenty of Teflon Tape on it and it shouldn't have leaked. I'm not one to over tighten things. When I took off the factory plug, it had an O-Ring on it. It didn't come out easily. It took a socket to do it.

The Veissmann LLH is nice because they offer the insulation kit for it. Which I used.

I knew that BSPT stood for something stupid. Stupid me for not figuring it out. Old age setting in.