Efficiency of old boilers
- Thread starter tonyo
- Start date
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Heating up the metal in the boiler and up the chimney/flue!
Yeah, unfortunately the other 35% serves to warm up your garden, (and maybe you kitchen, or whatever room the boiler is in!)
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There is a formula to calculate flue losses,but accept the fact that the best part of 35% is being wasted.You may argue that some heat is used from the boiler giving off heat from the heat exchanger/casing etc,but in reality this is a small percentage of the total losses.
Put your hand / face near your flue / chimney and you will soon feel where it goes....
....seriously.... don't do this, but the 35% flies off to heat the sky.
....seriously.... don't do this, but the 35% flies off to heat the sky.
I`ve got an old boiler - and with a bit o fettlin` I can get 69
I`ve got an old boiler - and with a bit o fettlin` I can get 69
You get fettlin, AND a 69?
How much of a difference would a service make to an old boiler's efficiency, say if it had not been done in over 10 years and was burning with more than a slight tinge of yellow
This is what I have pieced together, I hope it's not too wide of the mark:
Modern condensing gas boilers burn with a much richer mixture (less air for a given amount of gas) than old open-flue boilers or balanced-flue boilers. Some modern boilers even have a Lambda sensor to automatically control the mixture and use the minimum air; the less air a condensing boiler heats, the more efficient it can be.
An open flue boiler needs a lot more air in the mixture (and hotter flue gases) to reduce condensation in the chimney. Condensation had to be avoided in the old cast-iron heat exchangers, otherwise they could rust through. Old boiler casings were much warmer than modern boilers; the last balanced-flue boiler I had fitted in 1995 lost about 700W from the casing.
Modern condensing gas boilers burn with a much richer mixture (less air for a given amount of gas) than old open-flue boilers or balanced-flue boilers. Some modern boilers even have a Lambda sensor to automatically control the mixture and use the minimum air; the less air a condensing boiler heats, the more efficient it can be.
An open flue boiler needs a lot more air in the mixture (and hotter flue gases) to reduce condensation in the chimney. Condensation had to be avoided in the old cast-iron heat exchangers, otherwise they could rust through. Old boiler casings were much warmer than modern boilers; the last balanced-flue boiler I had fitted in 1995 lost about 700W from the casing.
I'd have thought 35% heat loss is a small price to pay for a relable, maintainence free boiler, even a new condensing boiler will struggle to give better than 10% loss and the savings are soon wiped out with repairs, not to mention the near certainty of having to be replaced much sooner than an old fashioned boiler. Also 69% [ after fettlin] is surely warm enough to make anybodies toes curl up
It's more wrong than right.
Fair enough maybe, but your response, as far as it goes, is not helpful.
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