Talk:Condensing boiler

Condensate Drainage
Questions: 1. Is it true that copper pipes should not be used for draining away the condensate, as the acidity of the condensate will react chemically with the pipe and eventually cause a blockage which stops the boiler from functioning? Copper pipes can't be used, but not for the reason given. When the flue gases condense, a certain amount of nitric acid is formed, imparting acidity to the condensate. This will react with copper to form highly soluble green copper nitrate. The pipe will be eaten away from the inside. That in itself won't cause a blockage, however, aluminium heat exchangers tend to create crystals which form in the condensate which may cause a blockage.Nick Hill (talk)

2. Would it be okay to connect the boiler condensate outlet to the (plastic) discharge pipe of a sink, using a plastic pipe for the connection? 92.24.32.32 (talk) 17:26, 17 May 2009 (UTC) That is a good way of disposing of condensate, as the external pipe will be a larger diameter than the common 22mm, thereby making freezing up less likely. The warm water from the sink will also help reduce the likelihood of freezing, and if it does freeze, will be apparent to the householder.Nick Hill (talk)

3. Freezing up of external condensate piping is a real problem - it happened to me. A boiler which does not work in freezing weather isn't a very useful home heating system, especially as a replacement for an older non-condensing boiler which did work in all weather until it needed replacement. Furthermore there is apparently no requirement to inform householders of the risk of freezing when a condensing boiler is installed. Should the Wikipedia entry discuss this issue? — Preceding unsigned comment added by 82.69.91.35 (talk) 17:14, 2 September 2018 (UTC)

What "output"?
I am a boiler novice reading the article for information. There is a sentence "To economically manufacture a condensing boiler's heat exchanger (and for the appliance to be manageable at installation), the smallest practical size for its output is preferred." I initially read "output" to mean boiler heat output (i.e. kilowatts), as that's what output usually refers to in this context. Having pondered on why this should be without success I now think it refers to the physical size of the 'exhaust pipe' (or whatever it's called) leading to the flue. Could someone who knows clarify the wording to make things clear? — Preceding unsigned comment added by Mark Triggers (talk • contribs) 08:31, 17 May 2015 (UTC)

Remove "myths" section
To refer to the complaints of some users of condensing boilers as 'myths' is just hocus-pocus. In my particular case, a five year old boiler totally failed due to the heat exchanger disintegrating. This is not a 'myth' as I did not make this story up. And I am aware of others who have had similar problems with heat exchangers failing. Please do not refer to actual problems as 'myths' unless you can substantiate them as such. Hippocrocopig (talk) 21:50, 27 March 2016 (UTC)
 * So source this. Yes, some boilers have failed after 5 years. It has more to do with quality, than with condensing per se. Andy Dingley (talk) 22:06, 27 March 2016 (UTC)

Well, you are still go2 have to remove the term 'myth' unless you can show that it is a "widely held, but erroneous belief" Otherwise it is just your opinion. And when you say " ... has more to do with quality ... " how do you know that? You are go2 have to substantiate that otherwise your 'myth' is no better than mine. Hippocrocopig (talk) 22:45, 27 March 2016 (UTC)
 * The difference is that the section here already has sources. Andy Dingley (talk) 22:59, 27 March 2016 (UTC)

Carbon output and Condensing Boilers - Economic Behavioural Factors
Carbon Costs of Condensing Boilers, Industry Financial Interests Rule - SEDBUK not fit-for-purpose and discredited -conclusion[edit]

Speaking as a scientist, medical lecturer, university lecturer/professor, and would you have it, commercial property developer, I do not speak without some forethought, unless I am inebriated at a party (sadly too rare).

I have been following the condensing boiler efficiency arguments and find the exercise mired in economic interests rather than science and engineering.

Firstly, few studies of value have been done to check the carbon footprint of the most efficient conventional cast iron heat exchanger boilers vs. condensing boilers.

My own carbon footprint calculations show that condensing boilers are four times, yes four times more polluting than the old conventional boilers, the main attribute here is the lifespan of condensing boilers is only 5-10 years, on average, yet the old boilers is 20-30 years. I have several conventional boilers that are 30-40 years old and still going strong. They are also almost 3 times the monetary cost of a conventional boiler to keep overall. Diogenes Loquitur (talk) 20:01, 22 September 2016 (UTC)

I have also interviewed 200-300 gas fitters (some like to call them gas engineers, sorry, but few are engineers in the classic sense, indeed they are not allowed to call themselves engineers with a capital E as this is a protected title in Europe, but that is another subject), the majority admit that they do not and would not install modern condensers in their own homes!! They also get very depressed with return visits when the condensers break down and they have to face the ire of the end user. A percentage (c.20%) have left the industry because of this alone.

When you add the breakdown rates, service costs, manufacturing costs, complexity of construction, the extra electricity consumption (circuitry and extra pumps and fans), the increased changeover costs, the high end level carbon footprint disparity emerges 'in glorious technicolour'.

But most gas fitters are there to make profit, and do not care about social order technical matters (-'we ain't social workers pal' -I use their own words).

Government GDP turnover increase from this poorly researched industry is approximately twenty-fold greater using this unreliable and short-life condensing technology. They (Govt) need the cash, not the detailed social studies. The public consultation that got condensers first approved was an industry whitewash (see below) and the BRE (Buildings Research Body) that later checked the technology in c.2003 could not find ANY fault in the boilers, declaring that their performance was identical to conventional boilers in all regards, but the gas used was much less (what ?? really !). This is exceptionally suspicious. Fuel poverty is still creating over 30,000 early deaths a year, I estimate 5,000 of these are from condensing boilers and their hyper costs and pollution alone.

Complexity as a way forward in most technologies is still lauded and sells well, conversely, simplicity is derided. (In health - my own field- complex drugs destroy more lives than they save, but pharma profits come first. Universities need complex patents to survive, watch how the news unfolds about complex ways of treatment.  Simple solutions are there, work well,  but 'cost too little', yes,  and bring in nothing in the new Uber-Capitalist Britain - so simplicity is unacceptable. The same with the heating industry, and indeed across many other industries, eg. motor.)

I spoke to a major worldwide boiler manufacturer, they largely agree (-backstage) with my figures presented here but say they are into profits and not social welfare. Well at least some honesty.

I spoke to an energy under minister in DEFRA, he told me they are NOT ALLOWED TO USE THE REAL RUNNING COSTS, MANUFACTURING COSTS, and REDUCED LONGEVITY COSTS IN CALCULATING THE SEDBUK RATING, which thus becomes a near irrelevant figure, derived from a laboratory bench test of just mere minutes with the boiler at maximum throttle in a rarely encountered cycle mode -  a mode that rarely happens in real life because unless  the return water temperature is well below a maximum return value so the condenser can work properly,  condensing mode is severely compromised; but if this is the case,  over-sized radiators may  then have to be installed as well (more cost, more 'luvli-phoni-GDP' out from the pockets of the poor and needy). In this compromised function state, a vapour plume is also visible from the flue advertising poor function. Sedbuk has nothing to do with real world sustainability, appliance lifespan, social cost, affordability, or real consumer pattens of use. It invariable does not save running costs, in fact...it is a bit of a silly rating to impress the plethora of uninitiated - the Emperor's New Clothes.

The condensing heat exchangers are prone to fail due to many issues, amongst them, particulate matter getting trapped in them (even with filters) and causing heat hot spots is a major problem.

The condensate itself is highly acidic and causes cement in drains to crumble -so collapsing drains. No worry, call the drain man, GDP will increase.

The turbo fans can fail causing carbon monoxide to leak into room space. No worry, fit CO detectors, GDP will increase.

But it is totally not advisable to use condensers with cast iron radiators or cast iron pipes as iron particles can lodge in the heat exchanger and cause explosions, again, even with filters. This is reported. No worry, that's Loadsa more GDP.

Condensers do save about 10-15% in gas usage in some cases. Many people however report no change in their gas usage or bills, in many cases any savings will then be mopped up by gas price hikes as turnover of gas companies MUST remain 'level high' for profits. Praise be to GDP.

There are those household users who see these condensers as a total panacea -the more complicated life is for them the happier they are- they may well be experiencing and 'tripping off' deep cognitive dissonance after the huge money they have spent and continue to spend on installs, repairs, and in monthly insurance costs or all three. Its the new S'Avoir Faire of the Uppity-Jones's. Indeed, you (and the new Uppity-Jones's) can now opt to lease hire condensing boilers, as they approach and sometimes exceed the cost of running a new lower end car (!!) even though they are just a glorified kettle. What superb marketing, superb concept manipulation, and government sponsored SED'buccaneer'd hoodwinking.

Conventional technology boilers could have been improved significantly (eg radiating the heat from the pilot inwards). Their use of passive (no electric fans to break down or consume electricity) balanced flues are EXTREMELY SAFE, probably the safest in the whole industry, as the boiler is totally room sealed for life. A heat recovery unit can be added on the flue side, or as I have done, the flue gases can rise over an air source heat pump external unit making the latter even more energy efficient down to -15C, currently heat pumps slow at -1C. However, these sustainable solutions do not liberally butter government's or gas fitter's parsnips. So we will continue to fail in designing sustainable and great technology when we try to use a committee the size of Belgium to design our fast horse that  now performs like a camel/walrus cross (imagine!),  but,  the economic triumph of the few at the top easily trumps the needs of the majority, and we can go for cam-rul rides?

So there will be no progress in this area (as no structured, truly indepenedent, empirical studies raised to clarify or challenge and test these arguments effectively are present), so highly partisan economic interests will dominate and GDP WILL prevail. (The fuel poverty death rates are merely collateral damage and unfortunate of course).

Also note, you are breaking Part L of the building regulations if you do not consider the environmental impact of installing, using and also considering the sustainable life of building methods and fixed appliances therein to minimise carbon footprints. We look forward to the first court case of a fitter not having done his her Part L homework. — Preceding unsigned comment added by Diogenes Loquitur (talk • contribs) 08:47, 19 September 2016 (UTC)

I (we) strongly advise homeowners to record the recommendations of gas fitters, sorry engineers, sorry gas fitters, in writing, and hopefully when the arguments have been proven one fine day (which they will), then seek COMPENSATION from the government, its agents, and the fitter for poor advice based on false premises. This may well be the new PPI scandal in waiting.

Super efficient conventional cast iron heat exchanger boilers can reach efficiencies of 85% and more. If the boiler (balanced flue) is mounted in an airing cupboard, a free drying room for laundry is available. And, lord be praised, if this type of joined up thinking is promoted, efficiencies exceeding 90% are easily achievable for conventional boilers with boiler lifespans of 25 years +. How disgraceful.

I request and challenge the government to do the research properly and stop the 'complexity is good' falsehoods across this industry. Benefits will include 6- 10,000 early deaths saved from fuel poverty, carbon footprints reduced by 75 % for this technology, and gas usage reduced when integrated spaces utilised (drying rooms/radiated heat facility/etc, etc).

Yours sincerely, Diogenes Loquitur

Postscript. I would be more than happy to produce the formal studies and so putting this matter behind us if the UK government would like to take me up on getting the studies done in a scientifically controlled manner and collecting real world experiences and data to nail this topic once and for all. I have several universities waiting to take these studies on. But that would cost GDP, and then reduce GDP when the studies are verified - so NO DEAL I guess. People must Suffer for British GDP Needs. Rest of the world, do not take condensers seriously at all, they DO NOT WORK. Insist on '25 year manufacturer-pays for the breakdowns' deal if you cannot resist them, as the conventional boilers can easily reach this lifespan target. Boiler companies, take the challenge of raising conventional boiler efficiency and selling to the world, it does work! Scrap discredited SEDBUK for a meaningful new sustainability inclusive index of total life appliance function; go on, I dare you, -you will make squillions! USA, home of the brave, this one may well pass to you in time as no one here will have the courage to admit errors. So see you over the pond! Another UK technology chance about to go, and a new tech conventional boiler industry about to go west.

Postscript 2. Think the condenser boiler market is worldwide? Think again. Few other countries use these infernal things, Britain, at the last count had over 50% of the worlds total market, making this technology very much a British mental obsession and pre-occupation. The best any other country can do is Netherlands with only 16% condensers, and Vorsprung Durch which only has a marginal 15% passion for this Technik. But Germans shrewdly make and flog most of their condensers to the UK, don't you know (they don't want them!).

Diogenes Loquitur (talk) 21:00, 18 September 2016 (UTC) also copied on Energy Discussion Pages


 * This (Wikipedia) is totally not the place for this. It's an interesting analysis, but WP is not the place for first publication of anything, by anyone. That's simply not WP's function.
 * I'd be interested to see your figures, as a model in detail rather than simply a conclusion. In particular, "Condensing boilers aren't all they're cracked up to be" is one thing, but "four times more polluting" is a serious claim and needs detailed evidence to back it up. Let's suppose that they self-destruct after a short time and make no evident savings. Can you really claim that their lifetime is only a quarter (and all of them, on average) of that for a non-condensing boiler? If there is an energy saving as well, and they last long enough that their gas consumption efficiency dominates over their manufacturing cost, then they would have to last no time at all! Your claimed 20-30 year lifetime for non-condensers is reasonably for the better makes, but it's not representative across the industry (and there's a reason why my failed Worcester Bosch non-condenser was replaced by a condensing Worcester Bosch). Andy Dingley (talk) 21:55, 18 September 2016 (UTC)

RESPONSE
That is why I call upon the government and the industry to join forces, and delegate the studies to a highly reputable totally independent university source or indeed several sources to produce the case controlled studies and finally the meta-analysis,  resulting in  independent conclusions from economically disinterested sources, that is most important. Surely that is worthy of WP and a conclusion which can be followed up. Diogenes Loquitur (talk) 22:25, 18 September 2016 (UTC)
 * If that was then published in a way that met WP:RS (i.e. a peer-reviewed scientific or credible technical journal), then that's just the sort of source that WP does want to make use of. Andy Dingley (talk) 23:16, 18 September 2016 (UTC)

Indeed. Meanwhile, strongly anticipating critical challenges in the final studies, and despite my already lobbying DEFRA to go ahead with these studies to no avail, I strongly recommend householders to keep records of installs and the reasons, so the industry, installers, and government can be potentially held to account for avoidable fuel poverty, pollution, and a failure to place the environment and health first, rather than  economic stridency and abetting group interests. I am also independently checking the carbon pollution factor as you kindly suggested and will report back. Diogenes Loquitur (talk) 08:12, 19 September 2016 (UTC)
 * Why blame installers? Andy Dingley (talk) 09:26, 19 September 2016 (UTC)

Having trained one of our employees in gas work through a local tech college and then a field work commercial company, first, we kept a close eye on teaching methods. The commercial partner in particular teaches them to 'keep in line' and strongly challenge customers and change boilers if possible...and more. One major boiler company actually 'induces' fitters with brown envelopes to go for broke, to only choose their boilers, and make sure their type are installed wherever possible and as fast as possible (-and earn a healthy kick back, £1000 in some cases),  I kid you not.Then, by using all the cards in the pack including distorting the initial gas training in the colleges about efficient operations and safety to insist/impress/force change, for example,   take silly unnecessary flue readings when none are required (gas safe corroborate this) -we had one guy try this one on us-  to 'prove' inefficiency, etc, I will spare the gore. Gas safe told us they had no control over this manipulative activity, so long as these miscreants had a gas fitters license they could go out and do what they want under present legislation as they were independent contractors. That is why we strongly recommend recording their advice on paper with their signature for 'future reference'. This component of sharp practice industry fitters is NOT a small one.

Installers (fitters) never refer to Part L and the need to stabilise long term carbon pollution, always citing Sedbuk ratings as the sole alter at which they  worship. Sedbuk is discredited in my eyes and needs serious review and upgrading to account for boiler lifespan, parts failures, etc, see above. You never hear fitters talk of the long term sustainability factors in any professional manner - indeed they have virtually NO TRAINING FOR THIS. Except, surprise, they don't fit condensers in their own homes if they can help it!! This is gross economic and professional duplicity. I would not accuse all, but most know of and many use these tactics to exploit. Some of the biggest firms, mention no names, are the biggest abusers.

Fuel poverty in Britain on the current scale is no laughing matter, indeed it is the worst in the western world per capita, worse than far colder countries. 30,000 + young and old die from it every year. I would like the abusing installers to be held to account, and the Sedbuk god to be debunked. I would also like the upstanding honest practitioners of gas fitting (indeed I have found one for our own use who refuses to behave in this dispicable manner)  to be held aloft in how practice should be done. This is why installers have to be thoroughly included in the rethink with new training and new sustainability practices,  fit for 2016 and beyond. I do not specifically blame them, but I do think they  have become  a very big part of a problem industry (now attracting many 'fast movers') that has to be brought under control and quickly. The change has to start with the studies I propose above, and you seem to agree with. Thank you for listening to me again. I would like to dedicate this material to JS, a highly honourable and client oreientated gas fitter, man and boy, who taught me much, now sadly passed on. Diogenes Loquitur (talk) 11:03, 19 September 2016 (UTC)
 * I've never had a fitter try to sell me a boiler. People who try to sell me boilers aren't fitters. So is the problem fitters, sales peoples, or fitters doing sales jobs?
 * IMHO, I like condensers and I hate poor quality boilers. I will cheerfully spend good money for a good boiler, and on the few occasions I buy boilers, this is what I do. Surprisingly, it's also cheap. I paid £1,600 for my last (supply and fit by a local firm) and that was not a penny-pinching exercise at all. So do boilers really cost everyone else £10,000?   No-one got a £1,000 kickback from mine!
 * Yet I also see people buying boilers (of brands I wouldn't touch) and seeing these 5 year failures. But IMHO, that's not condensing, that's brand quality. These were makes which had the same bad reputation 20 years ago before they were condensing.  If "the public must know!", then let's tell them that's there a brand quality difference first, not just tub-thump about condensing, same as people were doing about combis 20 years ago  (and who would oppose a combi these days?). Andy Dingley (talk) 12:04, 19 September 2016 (UTC)

Grateful for you prompting me to expand my views! As soon as the breakdown rate and lifespan of condensers reaches 25 years to match conventionals, I will call off the Hounds of Science, Sustainability, and CarbonFootprints. Inflicted technological redundancy saps human strength and spirit, reducing us to the lowest common denominators of big business - the ignorant, passive, and critically docile consumer. We need the formal studies, let us together ask for them and move from there, once the full unvarnished Diogenes Loquitur (talk) 19:12, 21 September 2016 (UTC)data is in. Have to sign off as I have said all that is needed. Grateful to all Diogenes Loquitur (talk) 21:07, 19 September 2016 (UTC)


 * I don't think Wikipedia is the organisation you are looking for. This is not a research body. Andy Dingley (talk) 21:49, 20 September 2016 (UTC)

Building Research Establishment
I improved the Building Research Establishment section, and fixed the dead ref. But the section still sucks. The section should be eliminated, and any useful information from the ref should be integrated into appropriate places in the article. Alsee (talk) 16:27, 28 September 2016 (UTC)
 * I would keep this section together, even if it moves into some other broader section on myths. The point is that a reputable body addressed the five main reasons cited against them - just look at the talk: page here for how persistent these are. Andy Dingley (talk) 20:23, 28 September 2016 (UTC)

I agree with Alsee that the BRE research has to be considered very suspect, should now be labelled as such, and degraded from reputable body research. I called them (BRE) and even THEY are distancing themselves from it, saying the research was performed under a totally different structure of the BRE, a structure that now has been disbanded with no one to answer for the conclusions. Why does WP not acknowledge that knowledge moves forward very fast due to the internet in particular, and that it is very salient to question the validity of any previous finding. The research conclusions of BRE should stay fully published, but dissent from their conclusions should be allowed to prevail at all cost, otherwise we would still be carrying the notion that quantum physics does not supercede Newtonian mechanics, or that the earth is flat? Diogenes Loquitur (talk) 11:30, 29 September 2016 (UTC)

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section: reliability
"A more significant issue is the slight (pH 3-4) acidity of the condensate liquid." i changed the term from 'slight acidity'. first i opted to remove slight, but then i settled with the current version because,(based on the pH value given in the 'exhaust' section) on the one hand it is 'slight' in the 'common sense' meaning it isn't a concern for the skin, on the other hand it is quite a concern in the technological sense for the corrosion effect in the long term operation. so to remove the ambiguity of 'slight' i added the pH value to this sentence (in case someone is not reading the article further - which happens to me quite often.) 80.99.38.199 (talk) 17:03, 5 October 2017 (UTC).

Discussion regarding reliability
At least in Germany, France and the Netherlands, condensing boilers have been the standard for decades. Since around 2010, conventional boilers can no longer be purchased in Germany, and only condensing boilers have been installed in new gas boilers since around 2000. In Germany, there has been a law for years that conventional boilers older than 30 years must be replaced by condensing boilers. Reliability of condensing boilers is not an issue (mine is from 2001 and runs without problems, provided some maintenance). The whole discussion about whether or not to use condensing boilers seems baffling, if not ridiculous. 91.64.168.106 (talk) 23:33, 18 February 2023 (UTC)


 * Feel free to edit the article Chidgk1 (talk) 18:20, 24 June 2023 (UTC)