Slow draining Basin

[NoviceBear]

I've just fitted a new 'bowl' type basin (i.e. with no overflow) and a chrome bottle trap (as under the basin is exposed I wanted it to look nice). Connected everything ok but the basin is very slow draining.

Could this be because of the bottle trap? Should I replace with an S-trap?

Or could it be something to do with the sink not being vented as there's now no overflow (because of the bowl type sink)?

There's definately no blockage as everything was checked when I refitted the basin and it was fine beforehand.

 

[Bahco]

Could it be something to do with the sink not being vented as there's now no overflow

Could be or could be no fall on the wate pipe or even a blockage.

Try an anti-vac trap first.

 

[Space cat]

Or could it be something to do with the sink not being vented as there's now no overflow

An overflow does NOT vent your waste pipe as you seem to think. It would stink if it did. The overflow joins the waste just below the plug but above the trap.

Check your waste pipe as Bahco says. It should slope downwards all the way. Any uphill section will give you loads of trouble. Can you give us some details on lengths and slopes?