I bought a used valiant eco tec 415 (paid £120 for a supposedly 6 month old one that had come from a demolition job) to replace an ancient inefficient conventional heat only boiler and had it fitted, my gas fitter didn't think it necessary to flush the system prior to fitting the boiler as all my radiators were getting hot and when drained down the water ran reasonably clear, he instead opted to fit a magnetic filter on the boiler return.
The replacement boiler has been noisy from the start kettling and pipes banging so first I changed the pump as I had a spare, this made no difference, then I added some fernox F2 boiler silencer which has reduced the pipe noise to just ticking but the boiler is still kettling quite badly, now as this is a heat only boiler it's my understanding that as it is just circulating the same water through it and not heating fresh water it can't become scaled so it must be blocked with sludge - probably from it's prior use, so I need to flush it through, my thoughts are rather than dismantling it to remove the heat exchanger that it would be quite easy to remove the whole boiler and take it outside and run a pressure washer through the water inlet and outlet pipes, but first I would like some professional opinions
The replacement boiler has been noisy from the start kettling and pipes banging so first I changed the pump as I had a spare, this made no difference, then I added some fernox F2 boiler silencer which has reduced the pipe noise to just ticking but the boiler is still kettling quite badly, now as this is a heat only boiler it's my understanding that as it is just circulating the same water through it and not heating fresh water it can't become scaled so it must be blocked with sludge - probably from it's prior use, so I need to flush it through, my thoughts are rather than dismantling it to remove the heat exchanger that it would be quite easy to remove the whole boiler and take it outside and run a pressure washer through the water inlet and outlet pipes, but first I would like some professional opinions