Recently when I was replacing a radiator I took the opportunity to give the sludged-up system a thorough flush after circulating Sentinel X400 for a few days. I rigged up a system to flush mains water through the boiler supply pipe and did each radiator in turn until the water ran clear. I refilled using Sentinel X100 inhibitor, put the system back into use, and within days the water in the expansion tank was black again, and the boiler much noisier than ever before. A jam jar full is completely opaque, with a brown scum on the top. I had a heating engineer look at it, but he doesn't know why this is happening, unless it's the two old cast iron radiators in the system. He suggested replacing my Glow Worm Space Saver 60B MkII, gravity hot water, with a Ferroli F30 combi, after power flushing the system. I suppose that's the easiest and most profitable solution for him (though he is the brother of a friend so I don't think he was trying it on). The house is a bungalow, and there's not much height difference between the cold cistern and the hot water cylinder, which I think might be the cause of the erratic 3 litres/minute supply to the bath hot tap. Changing to a combi should solve this problem and be more economical, but will the sludge return? One of the cast iron radiators has been repaired with epoxy metal repair where it developed a pinhole after blast cleaning and powder coating. Is the pressure in a combi system likely to be a problem? He says it would be a very straightforward job to replace the boiler, but hasn't given me a price yet. What do you reckon, to power flush, supply and change the boiler and take out the loft tanks and redundant pipework?
- posted
19 years ago