Ducati Sporting Club UK > General > Idle Chat > plumbing help please ??

[Nigel C]

spent all day trying to fix a problem with me mums washing machine instead of being out on the bike

frankly i'm baffled so if you can picture this can anyone suggest anything ?

there is a waste pipe behind the machine leading out to the drain via the sink waste pipe at the machine end there is a u bend and an upright pipe which the waste pipe from the machine goes into ok? .
waste water was coming out of this pipe when the machine emptied itself so i used caustic soda followed by boiling water and the water seemed to flow fine even put the garden hose in to flush any rubbish out but when the machine waste pipe was put back in water just came pouring out again tried again and it was ok then again and the water came pouring out

when the machine empties you can hear the water exiting into the waste pipe and then backing up the upright pipe and overflowing out even though there is no blockage in the pipe anymore , is it possible there is an airlock or air vacumn somewhere stopping the water flowing out ?.

sensible replies please my mums kitchen is very wet