Posted: Fri Aug 31, 2012 10:09am

Hi, we are baffled by an intermittent problem with our otherwise excellent macerating pump out toilet. After only a week since our last pump out, the tank swelled and a gush gave forth from the escape hole on the roof (unpleasant!) This seemed to indicate the tank was full, which it could not possibly be. After a while the selling of the tank disappears and all is well again, but it is scary! Any ideas?

Posted: Fri Aug 31, 2012 6:00pm

First I would question how you know the tank is not full if you have a macerator. With a dump through it is easy. How do you know the last pump out was done properly? Maybe something blocked the pump out pipe in the tank. I would say that what you describe is impossible because the breather pipe should be in the top of the tank and not extend down inside it so even if it did manage to pressurise you should only have gas blowing out. I wonder if you breather goes to the bottom of the tank. If it does then bacterial action could have made gas that could not escape, hence the swelling tank and the eventual gush. The tank would also swell if the breather was blocked and the macerator pumped more efluent into it. To be honest this all sounds very odd. Tony Brooks