Stubborn blocked sink

[Fredrick Skoog]

Hi All,

I've an problem with a blocked sink in my bathroom, no matter how much I rod it or stick chemicals down it, it stubbornly refuses to drain at a normal rate. It's not a type of sink I've seen before as it doesn't appear to have any trap, rather it goes through a couple of 90° turns before running down the back of the pedestal. There is an access point at the final dog-leg where I've rodded but this doesn't seem to make much difference, although interestingly there appears to be a build up of a vacuum which easing this access point off seems to alleviate and helps it to drain. I'm pretty sure that there is no major blockage further down as it drains to the same pipe as the bath which does empty ok (although it could be somewhere before the bath tees in).

Has any one any ideas?

Thanks

[John]

Re-plumb it.

[Matty F]

It's probably hair. Perhaps you can put a corkscrew twist in the end of a piece of wire and poke that down (or up) the pipe, twisting as you go. That could grab the hair so you can pull it out. But really you need to be able to take the bends apart for future unblocking.

[Fredrick Skoog]

That doesn't explain why loosening off the cap to the access increases the drain - in case you're wandering the water isn't draining out of the access in this case!

[meow2222]

for a tough job you can drill an access point at each turn of the drainpipe. a 4mm drill bit will do. You can then use a thin unblocker to either unblock or find exactly where the problem is. Holes can be covered later with a piece of rubber, a slightly bent washer and a cable tie. Saves taking it all apart.

NT

[TheScullster]

"Matty F" wrote

Agreed - particularly if you have someone using the sink to wash hair regularly. My wife's hair blocks the en-suite shower trap regularly and the other day my daughter blocked the bath trap in the same way. Stiff(ish) earth wire with a bend in the end will usually make a good fishing tool.

Phil

[Andy Dingley]

Aldi - about 4 quid, a really nice drain snaker.

[Mike]

I had a similar problem ....... When I loosened off one of the connections, air was allowed in and it drained normally. Further investigation along the route brought me to the hopper outside where the pipe discharged. The unsupported end of the pipe was sitting flatly on the base of the hopper and just about sealing the sink pipe. As a quick remedy I cut the end at an angle ... bingo !

Mike P

[Mr Benn]

A lot of the proprietary drain cleaners don't do very much. However Robert Dyas sell 98% concentrated sulphuric acid (labelled as drain cleaner). I cannot think of any organic material that won't be attacked by this stuff but be very careful in using it! It's also handy for getting rid of body parts. They also sell 32% hydrochloric acid, again labelled as drain cleaner.

Have you tried sodium hydroxide (caustic soda)? That will also break down some organic matter and is a little safer to use than the acid.

[Mr Benn]

I was thinking more of biological organic but you're right, polymer plastics could be affected by the sulphuric but the hydrochloric acid would be ok.

[PeterC]

That could be very nasty if too much added too fast to water or, even worse, some water spiled into it!

That'll clean off the chromium and, taking a bit longer, the stainless steel.

[The Natural Philosopher]

Don't bet on it. I've used brick acid (Hcl) and caustic a lot, and both do not good things to plastics. However a once in a while flush wont do any great damages.

I also think that caustic is worse danger wise than sulphuric.

Mind you, I pour in neat down the drain and follow up with a kettle of boiling water.

Its explosively boiling at that point and the pressure waves help to break up the sludge, but it does spit hot caustic up a bit. Old clothes, rubber gloves and glasses recommended.

Try a test outside to see what you are in for before doing in the kitchen.

[John]

....but they shouldn't block. Something is wrong - either the plumbing or your habits

[Matty F]

I think that rather than using the somewhat dangerous chemicals that are being suggested, you should get a standard U bend of the type that can be taken apart for cleaning, and hack out the pipes that you have into little bits. Then tell us what was causing the blockage.

[PeterC]

Or install a HepvO and be done with it.

[Fredrick Skoog]

Have taken further advice and this appears to be down to the wrong valve being fitted. Apparently there is a type of valve that lets the air in as it drains and then closes again. So my loosening of the connection would appear to be doing the same thing.

Repeated use of chemicals has removed the blockage thankfully........ Thaks for all the advice though :)