I have a slight issue! I will mention no names but a job has been done for me by a Gas Safe plumber which involves a condensate pipe going into a soil stack (at low level), the boss used is grey the pipe it goes into is orange, this has failed (very slightly but enough to cause damage over a period of time), my question is, "is it true that you cannot and should not solvent weld to orange"? and "should now this if he was a good plumber"? I am getting mixed info from my local people and would appreciate hearing from anyone of a similar position (qualification wise! not leak!).