Bath won't drain even with new trap

[RayC333]

Could the forum please help with a problem I have with my bath tub plumbing. I have a bath with an overhead electric shower and recently the waste water has been increasingly slow to drain.

I tried the usual clearing methods (which didn't work). Today I've removed the bath waste trap only to find it is clear, as is the (half metre or so) 40mm plastic pipe to the soil stack.

Using a flexi-wire tool, I can detect what feels like a spring loaded flap about where it enters the old cast iron soil stack. When pushing the wire I could hear/feel it open and close, so assumed on re-assembly it would work again .... alas not and the bath is full of water.

Is this some sort of flap valve problem? Why would it prevent the significant weight of water in the bath going out? Looking at the Screwfix catalogue I can't see any plastic end connector that incorporates a flap. Surely the flap is not part of the cast iron stack?

Any advice appreciated.

ps. The soil stack is in an open section of wall at the drain end of the bath. I can reach it but it is difficult to access.

 

[terryplumb]

Show us some pics of where the waste pipe joins the stack.
Have you fitted a brand new trap ,as stated in the title ??

 

[HERTS P&D]

Get a wet vac and suck on the waste pipe under the bath.

Andy

 

[RayC333]

 

[HERTS P&D]

Forget your wire spring, they just curl up in the pipe, use a wet vac.

Andy

 

[RayC333]

Yes, new trap fitted. Bath still full of water with no plug in it! Just used the spring when the trap was off. That's when I felt some sort of valve/flap at the stack end.

 

[Hugh Jaleak]

First point I would check is where the plastic screws into the boss on the stack, possible that's gunged/corroded up. I'm not aware of any fittings of that type with Non return valves in them, can only wonder if something has found its way down the stack that shouldn't be there....

 

[RayC333]

The soil pipe from the adjacent toilet enters the left side of the stack (just out of shot) and is vertically just above the waste connector in the stack, so I guess it's possible it might be gunged up. Toilet empties fine though.

 

[RayC333]

 

[Hugh Jaleak]

That is your issue in one photo. Regs state there should be no horizontally opposed connection within the 200mm below the centreline of the WC connection. It'll be blocked solid from the WC.

 

[Baths'N'Gas]

From the pictures, I’d take the toilet out and have a look into the 4 inch and you’ll find your problem, probably pee, poo and paper

 

[HERTS P&D]

But Hugh, that stack was built like that.

Andy

 

[Hugh Jaleak]

But Hugh, that stack was built like that.

Andy

Doesn't mean it's right though. (Although it would have worked when it was new!) Cant understand why they'd make a fitting like it, it's asking for trouble, (as well as being in contravention of the regs!)

Went to my Mates Parents house many moons ago, they had a basin in the downstairs WC that they hadn't used in years as it was blocked. Same issue, only it was connected directly opposite the sink waste, which also took Waste Disposer. Basin connection was rock solid with crud, I just capped it off and fitted a new waste from the basin to an outside gully.

 

[RayC333]

As you say, been like it since new (circa 1970). It's in a block of 10 flats. The soil stack is shared with one other flat (that is below this one). Not near an outside wall; MAJOR building work would be required to change its design.

Even if I take out the WC I won't be able to reach the junction, due to there being a right hand 90 degree bend at the loo end plus all boxed and tiled in. When the water subsides I'll try removing the pipe fitting at the soil stack and see what I find.

Concerned that I might damage a pipe fitting that is no longer available.

Edit: The cast iron soil pipes and fittings are part of the Timesaver range, introduced in 1973. Threads are said to be 2 inch BSPT so should be able to get a replacement plastic connector if I destroy the existing one.

 

[JimCrow]

What you have ther meets the requirements of the building regulations, the waste and the soil pipe centres are the same height on the branch.