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Several discussion items listed below express opinions that this article needs to be cleaned up. I whole heartedly agree. I am a professional engineer who worked as the head of engineering for an industrial furnace/oven manufacturer for 23 years. The article has some misleading elements and is substantially incomplete. I agree that the article should be split between comfort heating furnaces used in residential and commercial buildings and Industrial furnaces used in manufacturing. Also outdoor wood fire boiler has no place on this page.
So if the term in Britain mostly refers to a smelting furnace, what do Brits call the things that heat their houses? Oh, that's right, Brits are well-known for not having central heating . . . surely that's changed with the coming of the twenty-first century! ;)} jaknouse 14:19, 4 May 2004 (UTC)
Like the text says, it's called a boiler or a heater! Take a look at http://www.diydata.com/planning/central_heating/boiler.htm. In 2001, 91% of homes in England, 92% of homes in Wales and 93% of homes in Scotland] had central heating , a few percentage points higher than in a 1997 USA survey  220.127.116.11 15:58, 2 Jul 2004 (UTC)
Hmmmm... I can't believe that anyone would write an article on furnace without at least mentioning metallurgy. But then again, someone redirected smelter to forge. I guess in the wild west they meant much the same thing, but I thought that had changed, too. I've redone the intro to take account of the possibility that English Wikipedia may eventually become available outside of the USA. (;->
But all kidding aside, folks, I think we should seriously consider splitting the article, maybe into furnace (domestic) and furnace (industrial). What stops me is the extensive material already at furnace#Industrial furnaces. I haven't a clue where where all that comes from, or where it belongs. My guess is that it's US English again, in which case we need to find a term other than furnace (industrial) for the head article describing metallurgical furnaces. Maybe furnace (metallurgy)? Or maybe steal the article name furnace for the head article on metallurgical and industrial furnaces, and create industrial furnace for the detailed material under this heading, and furnace (domestic) and furnace (disambiguation)? Andrewa 18:26, 7 October 2005 (UTC)
- The references show a lot of heavy-duty textbooks; I reckon the text in 'industrial furnaces' comes from those books. I personally think that the 'industrial furnace' section could use some cleanup (too technical), but I don't know where to start, as some of that text is relevant. Sentinel75 08:07, 2 May 2006 (UTC)
- Dammit, hit 'save page' before I had finished thinking; who wants me to put a 'cleanup' tag at the top of this article? Sentinel75 08:08, 2 May 2006 (UTC)
How about "central heating furnace" or "warm air furnace" with disambiguation to bring furnace or other terms to it. Also, furnace (at least in the US) generally only refers to a heating appliance that uses air as the distribution medium. An appliance that uses hot water or steam as the transfer medium is usually referred to as a boiler. Maybe "central heating equipment" would be more appropriate if boiler and furnace are to remain in the same article. Also coal was once a common fuel for residential heating but is not very common anymore.
Also, the percentage of central heating in the US vs UK(in the discussion) doesn't account for areas of the US where the climate is relatively mild and central heating is more a luxury than necessity. Mattmia2 05:02, 15 April 2007 (UTC)
Cleaning up furnaces
I think the outdoor wood fire boiler section should be moved to the boiler page. It seems wierd to include it in the furnace page.
And, although the term furnace is itself very vague, one should try not to mix up the terms boiler and furnace or just a simple heater. Typical standards of definition would be by the type of fuel used. Another way would be by deducing whether only liquid phases are involved or both liquid and gaseous phases. Another way is whether it is used for chemical reactions, or just simply heating up stuff? This way, we can focus the page down. Otherwise, anything that burns something and produces heat can be called a furnace and gets included in this page. And with induction furnaces, it seems like anything that heats something else can be called a furnace.. Anchorage48 (talk) 10:39, 8 March 2008 (UTC)
Life of furnaces?
How long do furnaces last?
16:05, 5 May 2007 (UTC)
- It varies enormously based on the quality of the materials used, the fuel used, and the amount of maintenance performed. For household hot-air furnaces, the heat-exchanger usually sets the life of the furnace; once it fails, the cost to replace it may exceed the remaining value of the furnace, especially if the old furnace can be replaced by a new furnace with higher fuel efficiency.
- Atlant 22:54, 5 May 2007 (UTC)
Efair 15:07, 15 August 2007 (UTC) Organizing around or providing refernces to the variety of home heating devices might be helpful on this page, along with some discussion of what "efficency" means and the relationship of efficiency to the handling of combustion byproducts. Specifically from the Natural Gas perspective (which is most common in my part of the world) there are various techniques to handle those byproducts -- unpressurized metal ductwork, lined or unlined chimneys, or through pressurized piping. Some rationale of why to use each technique would be helpful.
Speaking as someone who lives in SW-Ontario (same climate as Detroit, Buffalo, Toronto) where the heating season starts late October and ends in May, it's not unusual for houses built in the late 50's or early 60's to still have their original natural-gas forced air furnaces, and certainly not unusual to see furnaces built and installed in the 1975 - 1982 time frame. That would put the working life well into the 30-year period.
Yes, the end of life usually comes because of a cracked heat exchanger, but also note that the air pressure of the household air inside the exchanger will be positive with respect to the combustion side, so air will tend to flow from the interior side of the crack to the combustion side - meaning that combustion gas will most likely NOT leak into the household air, but instead the household air will tend to leak into the combustion side of the exchanger, resulting in flame disruption if the leak is bad enough.
Old furnaces get a bad rap because of their constant pilot light, or poor efficiency electric motors. However, most of the efficiency gains of modern furnaces come because of better scavanging of exhaust heat, which is essentially an issue of "plumbing". Electronic ignition, and electronic motor control, are gimicks that contribute little to efficiency but add A LOT of extra maintainence costs when they break. And when you think about it, the heat of a constant pilot light is not really lost - it is seeping into the house one way or another. It's like the issue with incandescent bulbs. They generate a lot of heat, but that heat helps heat houses in the winter (and the winter is when there is less natural light vs the summer). So the waste heat from incandescent bulbs is actually not wasted during the heating season. —Preceding unsigned comment added by 18.104.22.168 (talk) 00:44, 3 November 2007 (UTC)
- Generally the longer a section of piping, the more resistance there is to airflow. Putting a forced-air furnace in the center of the building helps to keep the ducts about the same average length for all locations.
- For a corner-installed furnace, the really long distance ducts to the other side of the building will take longer to transfer heat than ducts near by the furnace. Small auxiliary fans can be mounted inside these long piping runs to help pull air through the very long tubes, or restrictive dampers can be installed in the very short ducts to even out airflow resistance throughout the whole system.
Merge "first fire"
- As long as the term is only used in furnaces, then I fully support it. Wizard191 (talk) 12:52, 13 September 2010 (UTC)
- I've never heard it applied to furnaces as such. Kilns mostly, also smelters and blast furnaces. Lighting a plain furnace is easy. Lighting a kiln (i.e. an enclosure of insulating bricks) is much more fraught, as they're the ones that can fail on heating and for which a successful first fire is thus a milestone. Andy Dingley (talk) 11:18, 6 October 2010 (UTC)
Modern Furnace Components
The paragraph on the ignition system seems to contradict itself (probably a typo). The article states
This produces a half-wave of electrical current from each full wave. The ignition control circuit detects the half-wave to determine if the sensor is merely touching ground.
The next sentence is the contradiction:
If the ignition control receives this half wave signal from the flame sensor then combustion will continue.
It seems that if the ignition control received this half wave signal from the flame sensor then combustion will NOT continue, since this is most likely a result of a short, as the paragraph mentions. The ignition control does not know if the flame exists during a short and so gas could be accumulating to explosive levels. Hence, it makes sense to end combustion when receiving a half wave signal.
Ekulrbx (talk) 03:47, 21 September 2010 (UTC)
Article has no focus
The edit I made at 9 december 2010 seems to have been reverted: Furnace&oldid=401454280 I wrote that " A furnace is a thermally insulated chamber (or oven) used for forging. " the revert was done because, as stated by Wizard191 "a furnace obviously has other functions too"; given that these "other functions" are about devices that also go under other names, and are even more correctly referred to by these other names, it destroys the quality of the article and the info is best placed at articles with their proper names. At present, the article is such a complilation of different devices that it's unreadable, please fix this, we require this article to have a standard acceptable by wikipedia . 22.214.171.124 (talk) 09:13, 10 December 2010 (UTC)
- I agree that this article is somewhat convoluted, however, instead of breaking each type of furnace into its own article, why don't we split it off to industrial furnaces and household furnaces? Wizard191 (talk) 22:41, 10 December 2010 (UTC)
- I don't find this a suitable division, ie if we would do it this way, we can never put down a good comparison of the types (ie regarding thermal efficiency, ...) Also, it would be confusing since a single type can exist in both categories, this makes things unnecessairily complicated.
Efficiency of furnaces
--> Not sure whether it's best to mention these here, or whether it's best to make new article pages for each type of furnace (this can only be skipped if this article is focused exclusively on metallurgy)
- using cokes:
- using electricity
- Ladle furnaces
Other older or specialised furnaces; including
- blast furnace, used to reduce iron ore to pig iron
- Puddling furnace
- Reverberatory furnace
- Bessemer converter
- Open hearth furnace
- Basic oxygen furnace
- Vacuum furnaces —Preceding unsigned comment added by 126.96.36.199 (talk) 14:29, 10 December 2010 (UTC)
"In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace (known either as a boiler or a heater in British English)"
Err hate to have to point this out but we (USA) call them heaters the most often (at least in parts of the country) or more specific terms as well, such as "boiler", "heat pump", "central air", "furnace", and so on.
I'm curious where the terms are used the most.
- It's probably a regional thing, because here in Chicagoland we call them furnaces not heaters. Wizard191 (talk) 15:01, 2 February 2011 (UTC)
Furnace manufacturer in India(therelek Engineers Pvt ltd)
We are the No1 Furnace manufacturer in india, we do different types of furnace and covers broad spectrum of our expertise in manufacturing the Industrial Furnaces and Ovens and also Heat Treatment Services that are offered by us — Preceding unsigned comment added by 188.8.131.52 (talk) 07:23, 2 August 2013 (UTC)
Tone of article.
Haven't read the whole thing, but the general tone of the part explaining single, 2-stage and modulating furnaces bothers me. It doesn't sound right to have it stating that a 2-stage is "better" than a one-stage, or that a modulating furnace is "most desirable". These are opinions, not facts. You could say that "many people consider" them to be better, but it sounds wrong the way it is. Not encyclopedic, and it almost comes across like an advertisement. Lets say, what if the person who wrote that also happens to be in the business of selling modulating furnaces, it seems like a conflict of interest. Yes, someone has listed some of the pros of a single-stage furnace, but I would rather see the phrasing changed to reflect the benefits of each type without actually saying one is better than another. Let the reader form their own opinions based on the facts (which is what an encyclopedia is supposed to contain...facts)..45Colt 12:29, 12 March 2014 (UTC)
Edit: in fact, considering that the links next to the phrases in the article direct you to a youtube video posted by a company that sells furnace equipment, I would say that it is very likely that it was written by someone who works for that company, and is in essence an advertisement posted on youtube. Isn't that against Wikipedia policy, especially providing a link to a page featuring your own company? Someone is using Wikipedia to convince people to buy their product, and supplying links directing them to a page advertising their company that sells that product. And I say that's BS..45Colt 12:35, 12 March 2014 (UTC)