Hi, hoping someone can help. Have had new shower fitted, tray and shower to replace a cubicle. Plumber left drain waste as was there before, he says he only added additional elbow to the what was there. It is a low level tray.
A few weeks after it was done, tray started to fill upto rim, never overflowing but quite high plumber advised to plunge it, so I did and it seemed to start draining ok. Then after a few days it started to slow down again and now at some point in each shower it all of a sudden drains quickly. So it will fill up about half way up to rim remain there for a while and then dispearse.
Any ideas why this is and what I can do to stop it?