Slow draining sink

[sau00btk]

Hi,

We've just fitted a new bathroom, although have used the original suite and soil pipes etc. In the process of removing the sink, the trap got broken. No big deal...we bought a new one and fitted everything back together. All worked fine until a couple of months ago when the sink started to drain really slowly. I've dismantled everything numerous times. The plug hole is clear, the trap is clear and the soil pipe seems clear. Plungng has no effect. The water will drain away (increasingly) slowly but there's obviously something wrong. I suspected that the fall from the new trap was too shallow so have tried increasing it by trimming some off the bottom of the threaded pipe from the plug hole. Still no luck. Any suggestions please?

 

[PrenticeBoyofDerry]

I suggest you check the length of the waste pipe for any obstruction.
Could be worth disconnecting the waste from the trap and pouring some water down the waste pipe to see if it is your waste that is blocked, if that runs clear, you can then assume the problem will at the sink trap.

 

[sau00btk]

Ok, so here's the latest. I have managed to pour 4 litres of water directly into the waste pipe with no problems. I have also simulated the trap by running water into the top of it and watching it empty through the waste connector (albeit not simulating vacuums etc). I have also poured enough extra strong drain cleaner directly down the waste, through the trap and down the over flow to kill a small horse. I have also tried re-plunging. There has been a small improvement but nothing to write home about. I have also tried blowing directly into the waste and I think there was resistance there but I'm not sure how much is normal. Would a no-vac trap help or am I wasting my money?

Thankyou

 

[sau00btk]

Fitted the anti-vac trap after giving another healthy dose of drain cleaner to the waste pipe. A couple of extra plunges for good measure and it's sorted! Whether it was a physical blockage that was dissolved and pushed by the chemical / plunger or it was an airlock that finally escaped I don't know.