Pan Connector to Soil Pipe - Cut or not to Cut

[DazJWood]

All,

We have an old soil pipe stack which has an inner diameter of 90mm. I presume it is a pitch fibre soil pipe (it's not cast iron).

I have been down the local plumbers' merchants and sourced a suitable pan connector, namely a McAlpine WC-CON7B.

The toilet outlet is around 30mm higher, (now that flooring and tiles have been laid), than the soil pipe, hence why this pan connector has been suggested, as it has a 14 degree offset.

Anyways, my question is around the connection to the soil pipe. Looking at the soil pipe, the inside surface appears to be very rough and I would question how well the rubber fins would seal against this. I presume normal practise would be to cut down the pan connector so that the rubber fin would sit at the end of the connector and then the rubber seal would be pushed level or just below the soil pipe. Looking down the soil pipe, it runs straight for a good 400mm or more before bending down and to the right. So for added robustness, I'm questioning whether I need to cut down the connector at all; leaving it longer would mean anything traveling down it would be well passed the end of the soil pipe and unless there's a blockage (connector end would be no where near the bend in the soil pipe) then gravity would prevent anything from trying to get passed the rubber fins. The soil pipe has a good decline on it. I realise the rubber fins are also there to seal against smells so am thinking I could add an additional seal; one at the end as usual on the connector and one further up that sits level just below the soil pipe.

Is this doable? Hope I have explained it well enough. Can you even buy additional rubber finned seals for 90mm pipes?
Anyone any thoughts on this or any other suggestions?

Thanks in advance,

Daz

 

[Timmy D]

You’re over thinking this. Just cut it to the required length and push it in.

You could also lightly file the inside of the pipe to remove the roughness.

 

[Last Plumber]

It looks like asbestos cement pipe to me. Don't damage it or you could release fibers.
Cut the plastic long enough so as the rubber fins are an inch back from the end and push it in so the fins are 1/2" back from the open end, if that makes sense? Then seal the end with silicone. White might look best.
From what you've said and what I've seen on the photo, that sounds the best to me.

 

[snowhead]

As above, I'd err on the side of it being asbestos.
As L.P re fitting the pan connector and then you MAY be able to get something like this to cover the old collar, check internal size first tho.

110mm Split Two-Piece White Toilet Pipe Cover Collar

Upgrade your toilet area with the split two piece white toilet pipe cover collar. Effortlessly install and enjoy a clean and professional finish. With its split design, there is no need to disconnect or remove any part of the pipe system.

plumbing4home.com

 

[Ben-gee]

Don’t worry about a slight roughness inside the pipe it really won’t matter; if it’s bad it will get “smoothed out” by “deposits” during use! Yuk.