I recently had to make a small change in the routing of the drainage from my sump pump. I chanced four fittings including one that finished up as almost an S so as to connect to main drain. My problem now is I have a constant banging in the pipes. It occures about every 15 seconds and it is 3 or 4 soft banging sounds then stops for another 15 seconds or so. I put my ear to the pipes and it is for sure coming from the drainage pipes but I can't figure out just where it is coming from. It is driving us crazy, does any-one have a solution Thanks
