I have recently had a new shower fitted in a downstairs toilet in my flat. There is also an existing bathroom upstairs. Due to the nature of the building structure, ex council flat with concrete floors, the shower has been installed with a trapless pumped waste, about 3 to 4 meters or so of purpose made grey rubber hose running from the tray outlet to the pump. My problem is that every time the shower is used there is a gurgling sound from the shower tray waste outlet which I suspect is air being drawn in through the tray waste outlet by the pump. The pump on the other hand is very quiet.
Is there a solution to this rather loud and distracting gurgling noise or is this relatively normal ?