Long story .. told by B.Gas engineer had sludge in system and get new system installed (called them in as system wasn't working).
Got advice and put cleanser and desludger in system for 4 weeks. As soon as introduced chemicals, rads downstairs went cold (didn't know to bleed at time - very dense about plumbing). Drained down this weekend. Two drainage points did not drain. Plumber came and cracked knuts on rads and water then removed and cleared one of drainage points. ALL WATER CAME OUT VERY CLEAN. Filled system up, first upstairs, then down. (One of bleed valves open on upstairs rad unfortunately). Then put anti-corrosion into system. Now boiler fires up for 5 mins, pump works but heating/hot water not working. Area between and either side of pump warms up and after an hour the water just below the pump actually starts boiling. Pipes cold either side of valves. My questions are: is this sludge, air lock or valve problem. Should I try and drain down again and flush through and then fill up again? Appreciate any help. Thank you.
Got advice and put cleanser and desludger in system for 4 weeks. As soon as introduced chemicals, rads downstairs went cold (didn't know to bleed at time - very dense about plumbing). Drained down this weekend. Two drainage points did not drain. Plumber came and cracked knuts on rads and water then removed and cleared one of drainage points. ALL WATER CAME OUT VERY CLEAN. Filled system up, first upstairs, then down. (One of bleed valves open on upstairs rad unfortunately). Then put anti-corrosion into system. Now boiler fires up for 5 mins, pump works but heating/hot water not working. Area between and either side of pump warms up and after an hour the water just below the pump actually starts boiling. Pipes cold either side of valves. My questions are: is this sludge, air lock or valve problem. Should I try and drain down again and flush through and then fill up again? Appreciate any help. Thank you.