Shower waste problem

[Inverness]

New house and smells comes from shower... It's a merlyn shower waste it's not like your usual design.
I've lifted up the chrome but or I'm I suppose to lift up the other bit to get the hair bucket removal out? This design I don't see where the seal is to stop smells through?? Any experience please shine over my direction. Also when you pee in the toilet you can hear it flowing through the shower waste?? Thank you

 

[Basher]

The part you show under the chrome cover lifts out. There needs to be water in the pot to act as the seal/trap, and that white bit needs to be in place as it has a rubber seal round the edge.
Is there water in it at the moment?

 

[Inverness]

The part you show under the chrome cover lifts out. There needs to be water in the pot to act as the seal/trap, and that white bit needs to be in place as it has a rubber seal round the edge.
Is there water in it at the moment?
View attachment 83899

Thank you.
There was some water when I looked inside. Should there be a oring seal? Also should you hear the water drain away inside the shower waste when your having a pee? Maybe when the toilet is flushed it's removing the shower trap??

 

[Basher]

Thank you.
There was some water when I looked inside. Should there be a oring seal? Also should you hear the water drain away inside the shower waste when your having a pee? Maybe when the toilet is flushed it's removing the shower trap??

Sorry I think I'm wrong about there being a rubber seal round the edge, that was an older model I'm thinking of.
I wouldn't expect there to be any interaction or effect from the toilet until you flush it, and if it's then pulling the trap water out, that smacks of a missing (ie no provision was made for fitting one) or faulty air admittance valve on the toilet soil pipe.

I have a new build property with a shower where the noise from an adjacent soil pipe comes through the shower waste, but no smells fortunately! Maybe you could try topping up the trap after using the loo, and see if the smell stops? That might indicate fitting an AAV could fix it (or it's fitted but it's stuck)

Can you see or get at any of the waste/ soil pipe arrangement in this room?

 

[fowlerboi]

Noise when you wee sounds like no trap seal. Gurgling when you flush would be a siphoning

My diagram below shows how they generally work. Take a look at yours and make sure its assembled right and has water to the right level.
I forgot to include on my diagram they often have a rubber seal on the top most part which inserts into the trap which prevents air bypassing the cup. Other wastes have a very tight fit to achieve the same thing

 

[Inverness]

Thanks. I removed the white thing and there was a oring that was slightly distorted which I'm hoping was the problem... When you don't know you can bet plumbing forum has the answers thanks