Quote:
Originally Posted by wdrzal
My post was made to make DIY guys aware of the combustion process and all the parameters that need to be known.(in the few threads I read it wasn't discused) I wanted to post another link that explained it better but I need a few more posts to do that.
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We don't talk about safety that much here, but not because we don't care about it. In most cases we just assume that DIY'ing something in a way that would dramatically sacrifice safety is out of the question. Yes, less than safe ideas do come up every now and then, but they usually are either dismissed right away, or it is noted that such a set up should be short term and temporary at best.
Thank you for making sure that safety doesn't get omitted.
Quote:
Originally Posted by wdrzal
BTW the op mentioned he had a coal boiler converted to gas. The combustion efficiency can be as low as 40% to 60%. thats means he's loosing 40 to 60 percent of the heat out the flue. Thats not good when modern boiler efficiency for gas is around 90%.
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I think you misunderstood - the furnace was bought as gas powered (Ariston Genus 23 RI). It is about 10 years old (though the pipes and radiators in the house are much older) and was ~90% efficient when new. Maybe I should use the word "boiler"? I always think of boiler as a big hot water tank, while my furnace is of the flow through design. Anyway, it will be inspected by a professional when heating season is over and that's who I plan to ask about reducing burner size.
EDIT: I've replaced 'furnace' with 'boiler' in my previous posts.
As for "excess air", the boiler is in the basement which is more than drafty - there is a fist-sized hole in the wall for fresh air, plus the garage next to the basement has cracks in the door that you can easily see through. I have no plans to seal up the drafts until the boiler is replaced with higher efficiency model with a closed combustion chamber in a few years.
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I posted the original questions on a local forum and someone told me that the difference between heating high and fast vs low and slow won't be measureable, but didn't say which is better
in theory. Also, it was remarked that reducing the burner size won't help much without reducing the size of the exchanger. I answered that in many cases (though I'm not sure if this also true for gas boilers) a larger heat exchanger improves efficiency, so reducing the burner would be similar to having a smaller model with a larger exchanger. The answer was that a heat exchanger that is too large may cause condensation, which is bad for normal gas boilers (but good for condensing models). I have yet to find any hard evidence on how heat exchanger size effects boiler efficiency. When does 'larger' become 'too large'?