Since fillting new toilet to existing 4" elbow outlet which goes into the downcomer, it freezes in the 4" elbow outside. When unfrozen cistern empties fast implying there is no blockage in elbow. Previous toilet did not do that for 30 years. There should be no water lying in the elbow to freeze. Toilet is connected to elbow with flexible 4" pipe. Is there a level issue eg toilet level too low or fall on elbow is too horizontal (difficult to see on current)?
Either standing water in the pipe is not draining away because of a blockage or incorrect fall and eventually freezes, or the cistern is constantly overflowing which means the ice builds up over a period of time eventually blocking the pipe.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!