Can anybody help. In November all radiators were hot apart from one in lounge downstairs, husband bled radiators apart from one in lounge as bleed key was too big. In the cold spell the other two radiators downstairs stopped working. Called someone in ..we thought it was dirt in pipes, fitted thermostats on radiators and put some cleaning fluid through.
a few days later radiators upstairs stopped working apart from one..person came back and drained system, still no joy. called gas board in and had boiler checked..boiler ok, said we had microbore piping and if we had it flushed may still not work..suggested replacing pipework and radiators which we have done..still the same.. pump in boiler been changed..still no joy..