I have an open vent, Y-plan system that was originally installed in my 3 bed semi in the late seventies. When I moved in some of the radiators barely functioned so I cleaned out the system chemically and added corrosion inhibitor when I refilled it. Later I replaced the valves with TRVs (and hence changed the circulant several times before refilling with inhibitor), replaced the worn out diverter head, and replaced the programmer. The system has been working reasonably well for several years now, but the ancient copper core Corvec Maxiflame is showing its age and I would like to replace it with a functionally similar boiler. Having seen for myself what a weak acid does to aluminium, I would like a boiler with a stainless steel heat exchanger. After some research I had narrowed down my choices to Alpha CD13R, Vaillant ecoTEC plus 415, and Viessmann Vitodens 100W.
I then phoned the plumber who fitted the (open vent, Y-plan) central heating in my last house. He came recommended, and indeed did a very neat job of installing a system which incurred no major repair costs in the ten or fifteen years I lived with the system. He told me that whilst he would be happy to fit a Vaillant, he had had problems with after sales service and his personal boiler of choice was Halstead. He also told me that he did not have the kit to power flush the system (because it was expensive), and warned me that in his experience power flushing was expensive (£600 - £700) and could cause more problems than it solved unless the system was bad enough that a strong magnet would stick to the copper pipes. He suggested a magnetic filter as an alternative, though he's not convinced it would be needed. This is contrary to the advice given on this forum, but I have to say that the Corvec has been working for thirty years now despite a serious sludge problem at one point and no service record. Is it just system boilers and combis that are sensitive to a bit of residual muck? On the other hand, Halstead appears to have a really bad reputation, so I don't know what to believe any more. Maybe it's just the Halstead combis that are bad...
Can anyone help point me in the right direction, please? What is your opinion of these various boilers? The main problem I have at the moment is the Corvec really needs the pump to be at 3, but for reasons I've not been able to figure out this results in air entrainment when the diverter swings from CH towards HW, so I would like to operate at 2 as this solves that problem.
The circulant runs clear, but when I take a rad off the wall for decorating I'll usually find a bit of sludge in it (ie flushing it with the hose pipe will result in some black water). Do I really need to spend £600 on a power flush, or would the magnetic filter be a more pragmatic option (perhaps with another chemical clean)?
I then phoned the plumber who fitted the (open vent, Y-plan) central heating in my last house. He came recommended, and indeed did a very neat job of installing a system which incurred no major repair costs in the ten or fifteen years I lived with the system. He told me that whilst he would be happy to fit a Vaillant, he had had problems with after sales service and his personal boiler of choice was Halstead. He also told me that he did not have the kit to power flush the system (because it was expensive), and warned me that in his experience power flushing was expensive (£600 - £700) and could cause more problems than it solved unless the system was bad enough that a strong magnet would stick to the copper pipes. He suggested a magnetic filter as an alternative, though he's not convinced it would be needed. This is contrary to the advice given on this forum, but I have to say that the Corvec has been working for thirty years now despite a serious sludge problem at one point and no service record. Is it just system boilers and combis that are sensitive to a bit of residual muck? On the other hand, Halstead appears to have a really bad reputation, so I don't know what to believe any more. Maybe it's just the Halstead combis that are bad...
Can anyone help point me in the right direction, please? What is your opinion of these various boilers? The main problem I have at the moment is the Corvec really needs the pump to be at 3, but for reasons I've not been able to figure out this results in air entrainment when the diverter swings from CH towards HW, so I would like to operate at 2 as this solves that problem.
The circulant runs clear, but when I take a rad off the wall for decorating I'll usually find a bit of sludge in it (ie flushing it with the hose pipe will result in some black water). Do I really need to spend £600 on a power flush, or would the magnetic filter be a more pragmatic option (perhaps with another chemical clean)?
