Went to a job today, close coupled concealed cistern in ground floor toilet was not flushing away properly. First try it was clearly siphoning - glug glug at the end of the flush. No ventilation; obvious really. Sure enough when I pulled off the front plate no sub stack, just a flexi into a vertical clay straight to the manhole. Pulled up the manhole - clear as a whistle. Took off the pan and poured buckets down the flexi; it didn't back up.
The lack of ventilation causes siphonage sure but does it also cause the pan to back up even though the soil pipe is clear, perhaps air locking the flush? There is no obstruction in the pan; checked that. Given that it's close coupled and concealed putting in a sub stack will be well nigh impossible and there are no other connections allowing me to fit a Hepvo to provide ventilation. Is there a right angled pan connector with an inbuilt anti siphon valve out there?
Anyone with experience of similar your advice will be gratefully received.
Tom
The lack of ventilation causes siphonage sure but does it also cause the pan to back up even though the soil pipe is clear, perhaps air locking the flush? There is no obstruction in the pan; checked that. Given that it's close coupled and concealed putting in a sub stack will be well nigh impossible and there are no other connections allowing me to fit a Hepvo to provide ventilation. Is there a right angled pan connector with an inbuilt anti siphon valve out there?
Anyone with experience of similar your advice will be gratefully received.
Tom
