Whats The Difference Between Type A & B Drain Cocks?

[TheOP]

As the title really. You can buy type A or type B drain off cocks for central heating, etc. What's the difference?


http://www.toolstation.com/shop/Plumbing/Valves/MT+Cock+Type+A+15mm+Plain+Shank/d20/sd2696/p71396

http://www.toolstation.com/shop/Plumbing/Valves/MT+Cock+Type+B+15mm+Plain+Shank/d20/sd2696/p70876

 

[Andygasman2010]

Don't bother with type B. It doesn't have a gland seal so when you undo it it'll leak. I can't see why they're even still in production! Probably because they're slightly cheaper.

If you're not sure what I mean look at type A, you'll see it has a knurled bit on the top (just below the square) which contains a seal. Type B doesn't have this feature.

 

[TheOP]

That explains why the one I'm about to replace stained the bl***y carpet last time I drained down!

Thanks very much for the info.

 

[htgeng]

That explains why the one I'm about to replace stained the bl***y carpet last time I drained down!

Thanks very much for the info.

And another tip which is not obvious even to many pro's. Don't solder them without first removing the gland and washer. Yes, I've seen it done!