Hi there, I know this sounds a bit simple but I have the attached drainage configuration in my bathroom and I've tried all the tools available to me - a pump jet, plunger and a 7m coil - as best I can on all the drain points with no joy.
Red blob is my soil stack where the shower, toilet and bath all drain slowly. Then showering or flushing the toilet causes the bath to gurgle and bring up water. I can't get my rod in under the shower and can't get past the junction just after the toilet but I have been able to easily thread the full 7M coil into the stack from the bath and I am happy that this is clear.
Could it simply be an air intake issue causing the problems? I have an AAV in the loft but haven't been able to check this yet. Do these things even fail? Are there any ways to diagnose lack of make up air being the issue?
Surely the bath wouldn't back up and gargle if the block was basin/WC/shower side of the stack? Or would it all gargle like this even if the block was in the main sewer somewhere i.e. beyond 7m down the stack?
Your thoughts would be very much appreciated!