E
evets51
I've got quite a longstanding problem with a 1.5 year old 18kw Intergas system boiler which takes over an hour to get all radiators hot - and even then they aren't scalding hot to the touch even though the water temp is set to 80 on the boiler.
Potted history - it was a replacement boiler we had put in when we moved in, to replace a 17kw Ideal boiler. Its a 5 bedroom / 17 radiator house, approx 2200 sq ft - most people seem to think the boiler is too small, however having put my details into the boiler size calculator at idhee.org (double-glazed, 270mm loft insulation, cavity wall insulation) it came up with 13.6kw. Also the previous owners, who I trust, assured me the previous lower capacity Ideal boiler coped adequately.
Its a microbore system - originally sludged up badly and heating performance was awful (rooms wouldn't heat up at all), but we had 2 power flushes done plus a load of Fernox sludge remover. The three worst radiators for getting hot are in the living room and hallway - I've taken these radiators off and run a hose through them and no sludge, so I'm reasonably sure the system is clean.
The boiler shortcycles all the time - so fires for the first 2 or 3 minutes, then backs off for another 2 minutes or so before firing again etc. If it was firing constantly and took an hour or more to heat up I'd believe it was undersized - but it can't be right for it to be shortcycling constantly like this? So yesterday I closed off all radiators other than the three which are the worst performers, and fired up the heating. All 3 radiators got red hot within 20 minutes (hotter than I've ever felt them) - hot at the top and bottom (even though the boiler still shortcycled).
Its been suggested that the problem is the pump not being able to move the water around the system adequately. I've no idea what the pump system on the Ideal was. I've spoken to Intergas and they tell me the pump on the current boiler is a "5 head" pump, but you can get a "7 head" pump as an upgrade - £140 for the part. Just looking for opinions on whether or not that is likely to be a big help and worth trying? We've spent quite a lot of money on powerflushes / having people in to add Fernox and drain the system etc, and one of the options on the table at the moment is ripping the whole system out and adding all new radiators plumbed in 15mm copper with a new, bigger boiler. Obviously that's going to cost a small fortune though so would like to avoid if possible!
Potted history - it was a replacement boiler we had put in when we moved in, to replace a 17kw Ideal boiler. Its a 5 bedroom / 17 radiator house, approx 2200 sq ft - most people seem to think the boiler is too small, however having put my details into the boiler size calculator at idhee.org (double-glazed, 270mm loft insulation, cavity wall insulation) it came up with 13.6kw. Also the previous owners, who I trust, assured me the previous lower capacity Ideal boiler coped adequately.
Its a microbore system - originally sludged up badly and heating performance was awful (rooms wouldn't heat up at all), but we had 2 power flushes done plus a load of Fernox sludge remover. The three worst radiators for getting hot are in the living room and hallway - I've taken these radiators off and run a hose through them and no sludge, so I'm reasonably sure the system is clean.
The boiler shortcycles all the time - so fires for the first 2 or 3 minutes, then backs off for another 2 minutes or so before firing again etc. If it was firing constantly and took an hour or more to heat up I'd believe it was undersized - but it can't be right for it to be shortcycling constantly like this? So yesterday I closed off all radiators other than the three which are the worst performers, and fired up the heating. All 3 radiators got red hot within 20 minutes (hotter than I've ever felt them) - hot at the top and bottom (even though the boiler still shortcycled).
Its been suggested that the problem is the pump not being able to move the water around the system adequately. I've no idea what the pump system on the Ideal was. I've spoken to Intergas and they tell me the pump on the current boiler is a "5 head" pump, but you can get a "7 head" pump as an upgrade - £140 for the part. Just looking for opinions on whether or not that is likely to be a big help and worth trying? We've spent quite a lot of money on powerflushes / having people in to add Fernox and drain the system etc, and one of the options on the table at the moment is ripping the whole system out and adding all new radiators plumbed in 15mm copper with a new, bigger boiler. Obviously that's going to cost a small fortune though so would like to avoid if possible!
