40mm to 68mm gutter drainage link

[BILLDIYNOT]

Hello. I recently had a loft conversion installed where there is a 40mm (43mm external) basin waste pipe positioned to come out vertically through the soffit of my bungalow and attach to a 68mm rainwater vertical downpipe some 3 ft away from where the 40mm pipe exits the soffit. This has been achieved by putting a 45degree bend on the end of the 40mm pipe and then the 40mm pipe goes, diagonally, into a 67.5 degree 68mm pipe connector installed in the 68mm downpipe. The 40mm pipe enters the 67.5degree connector, however, NOT at 90degrees. No rubber boss was fitted to prevent ingress of contamination. I have purchased such a rubber boss that will accommodate the 40mm pipe into the 67.5degree connector and prevent ingress of contamination, but, I believe, the 40mm pipe would need to go into the boss at 90degrees to make a proper seal. I have seen ads for 112.5degree 50mm bends but none that are 40mm. I have looked at the possibility of getting 50mmx40mm reducers and putting these either side of the 112.5 degree bend fitting but I am not sure how these fit together and don't want to waste money just finding out. Any suggestions to make this connection would be appreciated.

 

[blup]

If you are nor prepared to try the reducer, drop the waste vertically and connect horizontally (with a slight fall) to the drain pipe. Is there a soil pipe you could tap into to comply with regs.

Blup

 

[BILLDIYNOT]

I'm happy to use reducers. What I don't know is how the reducers work, i.e. are they only to be used in one direction or are they bi-directional ? Logically, I could fit a 40-50mm reducer to the 40mm waste coming out, then fit the 112.5degree 50mm bend to the 50mm end of the reducer, then fit a 50-40mm reducer ( install the reducer the other way around to make it an "increaser") to the exit end of the 112.5degree bend and then my 40mm pipe to the 40mm end of that 50-40mm reducer. But I don't know if the fittings allow that or their design will not allow it. Are one manufacturer's design compatible with other manufacturer's fittings ? e.g. Flowplast and Aquaflow. I haven't seen a 112.5 degree 40mm bend. Do they exist or do I have to take the 40mm to 50mm then back to 40mm route ? Thanks for your input.

 

[blup]

That might work but you may have to experiment as different manufacturers do use different size pipe/pipe wall thicknesses IME, however small the difference.

Blup

 

[BILLDIYNOT]

Thanks for your comments.