Kitchen sink dosnt drain as it should

[plumben]

Went to a job where the sink waste was level/falling wrong way

Waste run is 40mm,1.5m run into soil stack with a silly flexi instead of two 45 bends

Replaced the waste run, more than adequate fall on it now
Bowl empties fine if the plugs out and just running water down plug,

But when a whole bowl empties it goes then gets air locked then drains slowly,

Will a anti vac trap help, as can't really get a AAV in above spill over level

 

[ShaunCorbs]

does the stack have problems draining?

 

[Callum Curwood]

Is the sink over flow blocked up solid? I've had a few do that and stopped it draining well

 

[plumben]

does the stack have problems draining?

It's the ground floor flat in a 3/4 story building
With a shared cast stack, that I can't touch as it's shared

However the bathroom all drains fine according to customer

 

[ShaunCorbs]

It's the ground floor flat in a 3/4 story building
With a shared cast stack, that I can't touch as it's shared

However the bathroom all drains fine according to customer

havent you check first port of call, and any of the other tenants have problems ?

 

[plumben]

Is the sink over flow blocked up solid? I've had a few do that and stopped it draining well

I did think that might be the problem but I It didn't seem blocked when I had a quick glance up it,
But I was going to swap it when I go back with a anti vac trap maybe as the merchants gave me a round overflow instead of rectangular

 

[plumben]

Yeah all the downstairs flats in all the different blocks of flats have problems with the sink waste

 

[ShaunCorbs]

Yeah all the downstairs flats in all the different blocks of flats have problems with the sink waste

same problem with air locks? and is the stack vented?

 

[plumben]

same problem with air locks? and is the stack vented?

They all have the same symptoms, and all where originally installed with 0 fall on them,

The customer knows it'll never be perfect but, it's a bit of a pain the way it's slow to drain and dishwasher/washing machine end up coming out the sink when it air locks,

Could do with some recommendations whether to just try anti vac trap or stick a aav in but it'd be under the spill over level

 

[ShaunCorbs]

They all have the same symptoms, and all where originally installed with 0 fall on them,

The customer knows it'll never be perfect but, it's a bit of a pain the way it's slow to drain and dishwasher/washing machine end up coming out the sink when it air locks,

Could do with some recommendations whether to just try anti vac trap or stick a aav in but it'd be under the spill over level

you can try an anti vac trap prob wont work and no point in installing an aav under the water line