> I am currently installing a vanity unit sink to replace a pedestal
>> sink in our en suite.
>>
>> I have connected the waste to the existing 32mm stub using a pushfit
>> to solvent weld connector and a new bottle trap via a 90 degree >> pushfit bend. >>
>> The water runs from the sink very slowly indeed. I have held the
>> garden hose running flat out over the waste pipe below the bottle
>> trap and it copes with the flow, as did the previous sink. I am
>> wondering if the new sink for some reason can't suck air back
>> quickly enough to drain the sink at a reasonable speed. I have
>> plugged the sink and brim filled it and the overflow operates very
>> slowly. (it is possible to overfill the sink with both overflow and >> plug hole open!)
>>
>> I can hear glugging as the water drains, and the water can be heard
>> trickling down the vertical drop below the bottle trap moving very
>> slowly. I have tried swapping the bottle trap for a P trap but this
>> made no difference.
>>
>> Has anyone any ideas on this please. I was wondering if anyone
>> markets a vented trap to allow air to be sucked in - but I suspect
>> this would let water and smells out!
>>
>> Thanks.
>>
>>
>
> Did the old sink have an overflow and the new vanity sink doesn't ?
> If this is the fault, then you'll need one of these :
>
>
formatting link
> It's called an anti-siphon bottle trap and it allows air to flow back
> into the waste pipe and stops the suction from the water flowing down
> the pipe, sucking all the water out of the trap.
By coincidence I just had to fit one of these to daughter's bathroom basin but this was to stop smells because water in trap was being depleted by another drain on same waste run. £4.14 in B&Q