Blocked sink, with lots of failed "solutions".

[MidAtlantian]

I have removed the trap - it was perfectly clear - and run a snake down for 6 metres, encountering no obstacles at all (except for getting around the bends.)

I put acid down, and the sink clears to a very good, fast flow, but slows to a very slow flow after: from a few days to a few weeks. I've done this four times.

There is nothing unusual going down the sink. One person uses it to do hands and face washes, nothing more.

When it does slow, it flows normally for about a pint of water, then goes rapidly slower and slower, til the end of draining a sink full of water is really slow.

After I flush it with acid, it will flow much better. Then I pun very hot water down it and that seems to further speed it up substantially.

There is a toilet half a meter away that flushes fine, and I assume (?) that this sink drains into that downpipe.

The plumbing behind the sink is buried in the eaves of the house, behind a plasterboard wall with large stone tiles on it, so not very accessible.

Thanks for any help or suggestions. I really do not want to open the walls into the eaves!

Cheers,
MidAtlantian

 

[HERTS P&D]

Run lots of hot water down the sink to flush out any acid, then remove the trap and put a wet vac on the pipe work. This should remove any remaining blockage.

Wet vac from wickes about £30 -£40.

Andy

 

[MidAtlantian]

Thanks, That is a technique I have not come across, but it t does make sense. You would not expect to need as much force pulling back as you would need punching though a blockage.

But I think I need to wait until it is well blocked before I do this, and that could take some time, and even then, the size of the hole that lets "some" water though might be big enough to let "enough" air through for it not to help. But it is certainly worth a try, especially as I have a wet-vac. And it is certainly worth keeping in mind - as part of my "bag of tricks" for a total blockage.

Is there anything I have to worry about in doing this? Could a pipe collapse from the suction?

I will let you know how it goes!

Cheers,
MidAtlantian

 

[JohnD]

I have a feeling there is something in the soil pipe that "detritus" catches on to form a blockage. For example it might be paper catching on a rough joint or a nail. There is less likely to be "detritus" coming from the sink.

There is a chance it might be twigs or something birdsnesty fallen down the top of the soil pipe if it is open at the top

You may have to take the soil pipe joints apart to see.

 

[MidAtlantian]

Thanks for your response. If there were a blockage caused by the toilet, wouldn't that obstruct the flushing action? That works fine.

And taking apart the soil pipe connections means removing at least part of the wall to the eaves - along with the large stone tiles that cover he wall: which is definitely last-resort stuff for me.

There is a small possibility that the basin drains into another large down pipe (with a vent) that is perhaps 2 meters away. A shower drain, also well "built-in", is lass than half a meter from this drain. But that too seems to flow OK.

But I had a snake in a full 6 meters, and encountered no obstacles at all.

 

[petertheplumber12]

As long as you block the overflow with a wet flannel, try using a pressure pump or the one you can buy in a can with rubber seal for sink waste, do it with water building up in sink with tap running not with empty sink, works very well. Not expensive either.