Connecting small black alkathene (3/8"?) to 20mm MDPE

[aesmith]

Hi,

I need to connect up a new supply to some existing pipework, the problem is that the existing pipe is not 1/2" as I thought, but actually 3/8". Just over 17mm outside diameter, and 12.5mm inside (which is why I thought it was 1/2" nominal). The new supply pipe will be 20mm MDPE.

What are the best fittings in this smaller size? I've been using the Philmac "3G" parts which are great for larger sizes, but they don't go below 1/2" nominal.

Thanks,

Tony S

 

[JimCrow]

Philmac 1133 Universal transition coupling

 

[muggles]

http://www.yourdiyshop.com/philmac-insert-adaptor-red-20mm-12-93002

 

[aesmith]

Cheers. I found a fatter O ring which looks like it might work with the fitting I have, but it's going to be underground so probably better to get the correct thing. Expensive fitting though!

 

[aesmith]

http://www.yourdiyshop.com/philmac-insert-adaptor-red-20mm-12-93002

That's interesting, what fitting does it go with? One of their "3G" range?

 

[doitall]

It sounds like BS 1972 class D pipe so philmac light green insert

It will be marked on the wall of the pipe

 

[muggles]

http://www.yourdiyshop.com/philmac-insert-adaptor-red-20mm-12-93002

That's interesting, what fitting does it go with? One of their "3G" range?

It'll go into a standard 20mm joiner, you throw away the white grab ring and put that in instead

 

[aesmith]

Perfect thanks. We just picked up that adapter from local Plumb Centre, for 66p including VAT. I didn't finish the excavation last weekend in any case, so the job hasn't even been delayed by my initial mistake.