syphoning problem?

[Jack_B]

After emptying my washbasin, a gurgling noise continues for several minutes. This noise is also heard from the bath at the same time. It sounds as if air is being drawn in through the plughole and if I loosen the connection at the u-bend, I can hear air being drawn in. Any idea why this is happening and how to fix it?

Jack

 

[phhut]

take a look at the outside gulley or drain-pipe - is it blocked? If the waste pipe end is submerged it makes 'gurgling' noises as and when air can get into the flow. Could also be partially blocked pipe - try plunger on it, or Mr Muscle.

 

[kevplumb]

could try anti syphon traps is the bath and basin wastes teed together ?

 

[Jack_B]

Unfortunately both the basin and the bath drains disappear into a concrete floor. I asume they must be teed somewhere as the noise can be heard from both. They do both seem to drain away okay, apart from the noise! What does an anti syphon trap do? Does it replace the existing trap? (The bath has a shallow trap and the basin has, I think, what's known as an S-bend)
Jack

 

[kevplumb]

lets air in to stop exactly the problem you have