Constant toilet blockage - insufficient fall from toilet to vertical soil pipe?

[HerrB]

View attachment SoilPipe.pdf I had a go and drawing a diagram of the issue, apologies for the terrible drawing but I always struggled in art class...

 

[Centralheatking]

Its a fine drawing - well done HerrB - CHK we will have more clus now CHK

 

[Reg Man]

No open vents or AAR valves. That won't help.

 

[Centralheatking]

I agree with Reg Man the system appears to not vented - maybe a dirgo ie non rtn
air valve might help - but how this stands with building regs not sure CHKing

No open vents or AAR valves. That won't help.

 

[stevetheplumber]

yes its probably airlocking as theres no air getting in behind the water plug even a 50mmm durgo after the pan would probably cure the problem idealy the four inch should go to atmosphere after the pan

 

[phil the bucket]

Is it an old syponic toliet as prop can arise when the wrong sypon is fitted (need to keep the ball inside )
Has the sypon been changed does it look new .

bit strange how it's been working for 10 yrs then suddenly starts to block especially on the top floor of a high building is there prob in the floor below ?