New shower not draining properly, maybe design problem?

Hello. I had a new shower put in last summer and it has never drained properly. It has a shallow tray and overflows easily due to the very slow rate of drainage. I know this is a common problem but none of the usual culprits seem to be causing it. Here are the facts :

• There was no drainage problem previously when it was a bath
• The waste pipe is going down at a 45° angle for about 12" and then flat
• No uphill or sagging sections
• Waste pipe is about 6 feet in total
• Waste pipe not shared with basin etc
• No blockages found with long spring
• Chemical unblocker does nothing.

I've attached a photo of the waste trap from the top. Seems like a daft design. Could there be air in it causing the problem?

Any help would be appreciated.

 

Maybe there is no specific fault or blockage and flow exceeds drain capacity and of course little margin for build up because the tray is so shallow...No expert but 6 foot drain is fine even with shallow fall...Trap seems the culprit..Maybe somehow it is airlocking.It looks a v v small hole

 

The water really hardly goes down at all, it's definitely way slower than it should be.

 

Do you have Access to remove the trap, and are any components of the trap removable from above ? I can't make out from the pic ,what's inside the trap inlet ,and don't recognise the make or how it's constructed.
I assume that some fancy 'cover' was removed by you to take the pic ,does it drain better when said cover is not in place ?

 

Hi. I removed a plastic/chrome piece from the top that has no effect on how well it drains. There are two screws I can undo (seen in the first section). This removes the circular piece in the photo and exposes the underneath section. As far as I can tell there are no serviceable parts in there, it just wobbles around a bit. I've attached another photo. I can't access the trap from below unfortunately, I can only see the pipework from the side.

 

Sorry ,I have no idea what the internal parts are of your trap. But if you can't access from above to clean it ,it doesn't say much for the design. It looks to be restrictive to me ,and I suspect it's the reason for your problem.

 

Yeah I agree with you. Dumb design. The reason I can't access it from below is because of how the cowboy builder built a base for the shower tray. I'd have to dismantle the whole thing to get access.

 

Can you show pics ,from the side of the tray ? Of the base .

 

Looks similar to a trap I was once supplied with a tray by a customer (might be wirquin), I threw it away and used a mcalpine.

 

Looks misaligned to me as well. Agree with Terry, it looks restrictive already.

 

I think it looks misaligned ,as it's "floating" once screws are removed.

 

It's almost impossible to take a meaningful photo but I have attached two. The first is directly underneath the trap. Then the pipe exiting that section to the right. The photos don't show everything under there but I just don't have more access than that.

 

The section underneath aligns properly when the circular top section is screwed back in. That section holds the underneath section in place.

 

Jeeeesus !!! What a ball ache !

 

I don't know if it makes any difference but i found out the exact trap being used. It's this one.