Internal soil stack too low

[mark270]

I have moved into a new house a year ago, and only recently when you flush the upstairs toilet water and air starts coming out of the bath, and the water level in the toilet rises.
I have an internal soil stack which is lower then the toilet. I know it should be higher but it is under the Bath.
If I hold the soil stack valve open and flush the toilet its all ok.
At the moment I have wedged the valve open.
Please has anyone got any ideas, with the last resort being to higher the Stack...

 

[seco services]

sounds like the durgo is faulty so just change it.
if the stack is lower than the overflow level of the highest appliance the basin then you'll need the A1 durgo valve.

 

[mark270]

Sorry I forgot to mention I have replaced the Valve, with no joy..what is an A1 valve?

 

[seco services]

an A1 can go below flood level B1 gos above flood level.
have you checked the drains etc are not got any blockages ?

 

[mark270]

Big Thank you for your advice and help, You are the Best, My outside drain is blocked solid, Luckily thats covered by my insurance, so they are coming around to unblock it

 

[seco services]