I want to get a central heating engineer to replace an old boiler with a new combi. Just wondering if I should replace all the old radiators, first. A plumber told me that old radiators can explode with a combi. If I do replace, anything else I need to know? Many thanks.
Does a combi need new radiators?
- Thread starter NickStone
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If you were to have a completely new ch system fitted then by comparison the new radiators would be larger, as new condensing boilers need to run at a flow temp ideally around 60C, therefore you need larger rads to get the same heat to the rooms.
Plumber is referring to combi systems being pressurised but the thought of a radiator exploding is a little extreme
The main problem you might get, although extremely unlikely, is that after power flushing with a proper cleanser you may get a leak in an old rad that was corroded internally, or a joint in the pipe work.
I never replace rads as standard on boiler replacements but always have a clause saying that any leaks found after flushing will be repaired but not included in the quote.
I also have only had a couple of systems that need the boiler to run above 65C to heat the property up enough. Usually over the years the property insulation has been improved etc so existing radiators will be oversized anyway
Plumber is referring to combi systems being pressurised but the thought of a radiator exploding is a little extreme
The main problem you might get, although extremely unlikely, is that after power flushing with a proper cleanser you may get a leak in an old rad that was corroded internally, or a joint in the pipe work.
I never replace rads as standard on boiler replacements but always have a clause saying that any leaks found after flushing will be repaired but not included in the quote.
I also have only had a couple of systems that need the boiler to run above 65C to heat the property up enough. Usually over the years the property insulation has been improved etc so existing radiators will be oversized anyway
Thanks, Gas4you, that's very helpful. There are in fact signs that the old radiators have been leaking (stains under the valves) and as I'm putting down a new strip wood floor, I'd better get those fixed. But not as bad as completely new rads.
Nick
Nick
If the old valves have been leaking, now is a good time to fit nice new TRVs; and, on the ground floor, a few lockshields with drain-off incorporated (if your downstairs rads are fed with loops from the ceiling, you need a drain-off on every downstairs rad).
If you can afford an extra £100 or so, a Magnaclean can be fitted at the same time as your new boiler, and will trap the disturbed black sediment that circulates even after a flush.
If you can afford an extra £100 or so, a Magnaclean can be fitted at the same time as your new boiler, and will trap the disturbed black sediment that circulates even after a flush.
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