plumbing help please ??
 

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

frankly i'm baffled :puzzled: 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 :puzzled:

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 :(

First of all I would take the stand pipe apart. The flow of water can be that great from a w/m that it can not get away in time. Also check the hose pipe for splits..

Depending on what type of waste you have, some waste pipes go out through the wall and into a back inlet gulley,this is another form of trap ,these can block and stop the flow of water causing a back pressure. Another one can be bends in the waste pipe the first couple of bends may be clear but if the last bend in the system is partially blocked again this will cause a back pressure . If it cannot be rodded, get a compression coupling ( Macalpine) cut into the pipe and inspect it ,clear it, then reconnect with the coupling. 4D