condensing oil boiler upgrade

oldsmokey

Hi all, our old Grant boiler has packed up, am looking to fit a Grant vortex condensing boiler - the house is 30 years old, so theres very little by way of fancy CH controls in it - the boiler house is right next to the house.
No TVR s or room temp switches fitted - Boiler heats the hot water cyl - no back boiler.
What do you suggest fitting to the system as we fit the new boiler to make the old place a bit more comfortable / efficient?..insulation is adequate.
I read something about compensation units to be fitted to the boiler?..good idea?..anything else?
Oh, we've approx 10 rads in the gaff..all 'old style'..
Thanks..

DoneDL

Fit trvs to your radiators except where the room thermostat is fitted, zone upstairs, downstairs and the cylinder. Make sure all accessible pipework is lagged, get the system balanced and make sure that all heating controls provide boiler interlock ie stats turn the boiler off when satisfied. If the cylinder is old upgrade to an insulated cylinder.

Iwannahurl

Be careful. Very careful.

Why fork out for a condensing boiler if you're not set up to use it at optimum efficiency?

A condensing boiler should do just that.

The return water temperature needs to be low enough to make the condensing process work, otherwise the boiler will be operating at less than maximum efficiency.

Here are some links where this issue is discussed.

http://www.cibse.org/index.cfm?go=discuss.viewthread&item=1%7C913

http://www.viessmann.com/com/en/press/press_releases/system_technology/Viessmann_Tieftemperatur-Heizkoerper.html

http://en.wikipedia.org/wiki/Condensing_boiler

245

So is there an argument for upgrading radiators (maybe overspecifying them?) to achieve the necessary heatloss in the in the system? George (in the first link) seems to be suggesting that.

heinbloed

Iwannahurl is correct.

It makes no economical sense to install a condensing boiler when it isn't used in the condensing modus. Some of the previous threads here in the forum dealt with this issue already. And showed a shocking ignorance of some self-styled installers.

It can be illegal to run a condensing boiler in a non-condensing modus, check the manuals of the particular boiler. If in doubt ask for an official statement, signed and sealed by the manufacturer.


245 asks:

So is there an argument for upgrading radiators (maybe overspecifying them?) to achieve the necessary heatloss in the in the system?

In lay men's terms: yes.

However the term overspecified is nor correct if the radiator is correctly specified. Taking into account the flow and return temperature a radiator must be specified, this is is the only correct method to specify a radiator.

There are more methods to achieve low (condensing !) return temperatures, for example running parts or all of the return through a 'cooler' , a wall heating/ UFH supplied by the return pipe. Or similar.

There are also flue gas condensors available, using the cold incoming air (needed for combustion) to cool the outgoing flue gases. This will cause the flue gases to condense . A condensing boiler is not necessary to run an oil boiler in a efficiency modus of over 90 %.

A heating engineer will tell you more. Or try google for " flue gas condensers " or " flue gas heat exchangers " or a similar term to get you a first insight.

Thanks for the links, Iwannahurl.

heinbloed

heinbloed wrote: »

.

It can be illegal to run a condensing boiler in a non-condensing modus

:pac::pac:
You are silly, again Heinbload a condensing boiler will always produce condense up to the point the return temperature becomes to high, Heinbloed the only difference between a system designed to have a low system temperature and a system designed to have a high system temperatures is the volume of condense not that one doesn't produce condense and the other does.


Also I would personally have a non condensing oil boiler as I think they are a simpler boiler but if a condensing boiler is fitted in a system that doesn't encourage condensing then you take off 3-4% of it's efficiency rating which still makes for a decent boiler compared to what it's replacing.

heinbloed

heinbloed wrote: »

Iwannahurl is correct.

It makes no economical sense to install a condensing boiler when it isn't used in the condensing modus.

That i agree with (God help me:D)

Op the more control you have over how your heat the better have a look at the link for further Info





http://www.centralheating.co.uk/system/uploads/attachments/0000/0157/CE51_CHeSS_WEB_FINAL_JULY_081.pdf

heinbloed

Gary71 wrote:

...a condensing boiler will always produce condense ....

What is "condense", gary71 ?

heinbloed

Oldsmokey asks:

What do you suggest fitting to the system as we fit the new boiler to make the old place a bit more comfortable / efficient?..insulation is adequate.

Correct, insulate your place.
Get a proper heating engineer, one who knows how to do an energy demand calculation according to EN 12831. This is legally demanded, most self styled installers are incompetent to do so and just install an overdimensioned boiler since they don't know any better.

Engage a heating engineer who knows how to optimise a heating system.
Balancing flow and return, installing TRVs instead of so called " zone controls " and " pumped zones " etc...

And if you don't trust the job there are devices available who control the efficiency of a condensing boiler. Court proofe, water tight ( smiley).

Here two of the condensate meassuring devices from Germany, check your heating engineer if he knows a similar device resp. if he could install one:

http://www.ihks-fachjournal.de/files/FJ_PDF/2005_2006/Effizienzmessung_bei_Brennwert_Heizungsanlagen.pdf

and

http://www.brennwert.de/index.asp?art=brenncon

There are similar devices for the 'English market'.


These devices meassure the condensate. Liters or milliliters per day, per timing. Once you have this number and you know your fuel consumption (gas meter, oil meter) you know the efficiency of the boiler, of your heating system.
If the number doesn't match what was ordered : money back.

The cowboys fear such controlled jobs, so it's a good idea to ask for a guaranteed efficiency before the contract is awarded.
If you fear incompetent installers: make a water tight contract.

heinbloed

heinbloed wrote: »

Gary71 wrote:




What is "condense", gary71 ?

If I could spell I'd have a proper job.

(If my spelling is right then it the term used to describe condensate)

Avns1s

gary71 wrote: »

If I could spell I'd have a proper job.

Lol, I think it's spelt right but the term is possibly "condensate". http://en.wikipedia.org/wiki/Condensate

Now, if I am correct, where do I apply for this proper job?? :D:D

Iwannahurl

gary71 wrote: »

:pac::pac:
Also I would personally have a non condensing oil boiler as I think they are a simpler boiler but if a condensing boiler is fitted in a system that doesn't encourage condensing then you take off 3-4% of it's efficiency rating which still makes for a decent boiler compared to what it's replacing.

I'm not going to argue the technicalities.

However, IMO the general issue is as described above.

The question is, to what extent is a condensing boiler's efficiency compromised by a less than optimum installation?

I don't know what the cost difference, if any, is between a condensing boiler and a good quality standard boiler, but it seems to me to be a waste of time and resources to install such a boiler and then not run it at optimum efficiency.

A 3-4% reduction in efficiency doesn't sound like much, but personally I would need to be convinced that this would be the actual reduction and that if a condensing boiler costs more the extra expense would be recouped in a reasonable time period by any increased efficiency.

The whole system ought to work in an integrated manner, IMO, and it's possible to imagine a situation in which effort and resources are wasted on installing technology that is theoretically energy efficient but which will never provide a decent payback because it is being deployed in less than optimal conditions.

You can't make a silk purse out of a sow's ear!





EDIT: Watch to the very end of this video for a brief comment on the general efficiency of standard versus condensing boilers...

https://www.youtube.com/watch?v=6GQ_QLaSbMo

heinbloed

Gary71 has never meassured the condensate, Iwannahurl.
There is absolutly no experience from this side. Statements as above (3-4% loss of efficiency) are absolute rubbish, no scientific (meassured!) evidence exists.
Gary71 obviously neither has seen an operating and condensing boiler. Otherwise there would be facts.
But only words.

I meassure the condensate from my boiler. And compare it with the fuel consumption. So I can put numbers on the the table, resp. can confirm official research, official teachings:

Prof. Floss ( Fachhochschule Bieberach , a trade's school for heating engineers) has published this pdf document

http://www.ihks-fachjournal.de/files/FJ_PDF/2005_2006/Effizienzmessung_bei_Brennwert_Heizungsanlagen.pdf

It's all in German, for his students, so we concentrate on table 1, page 1:

Here we see the drop of firing effiziency ( the blue curve ) going from 112 % in full condensing modus down to 98 % , the non-condensing modus.
A loss of 14 points in effiziency (!) between full-condensing and non-condensing modus, described is natural gas (Methane).

I might quote from the document, page 1, second and third column:

" Solange die Abgastemperatur ueber der Tautemperatur ( abhaengig vom Brennstoff und vom Luftueberschuss bei 56C) liegt, faellt kein Kondenswasser an "

Translated to:

"As long as the flue gas temperature is above the dew point temperature ( depending on fuel type and exess of air at 56C) , no condensate water is created."

This is official teaching. And my meassured experience.

Statements as from Gary71 (and several other frequent posters here claiming to be boiler installers) denying meassurement results which everyone can measure at home on a DIY scale ( with a bucket) show a shocking incompetence.

Germany's construction market is calling for competent builders. For competent heating engineers, new builds up by 30% this year, the home heating efficiency legislations sharpening on an anual scale. Switzerland and Austria made it upards as well, they had hardly a dip in the last few years.

A lack of English spelling competence will be forgiven when aplying for a job there.

The incompetence regarding the laws of physics the Irish academics employed in the construction sector are calling conservatism :

http://www.irishtimes.com/newspaper/features/2011/1107/1224307163352.html[/I]

50% of all Irish architects will have no chance to find a job. Nowhere, never. What's about the plumbers ?

Plombier

I read something about compensation units to be fitted to the boiler?

oldsmokey your own suggestion regarding weather compensation was the most knowledgeable post here, throughout most of the heating season it will serve to keep the return temperature below the condensing temperature of the flue gasses thereby maximising boiler efficiency. Talk to whomever suggested this.

heinbloed

Weather compensation makes sense where the internal heat load is depending on the time, on the date.
But not where the internal heat load is frequently changing because of changing usage of the structure, because of passive solar gain.

A standard family home with south facing windows and insulated according to building regulations will have no benefit from a weather compensation.

When the sun shines during the cold heating season and is warming the building via the windows the weather compensation unit does not sense this - it is shaded.

When cold sleet and rain hits the facade and causes cooling of the structure the weather compensation unit does not sense this - it is shaded.

If the night is clear or cloudy - the weather compensation unit does not sense this.

When the open fire is running and the kitchen in full swing the weather compensation does not sense this - it is not there but outside, shaded....

Ask a heating engineer about the exact calculations.

Or buy a magnet for the fuel pipe in your car, it's even cheaper.

Plombier

Don't be stupid a simple sensor inside the house will correct for any of these issues, read a little more on the subject and revert to me when you understand how it works.

heinbloed

heinbloed wrote: »

As long as the flue gas temperature is above the dew point temperature ( depending on fuel type and exess of air at 56C) , no condensate water is created."

gary71 wrote: »

:pac::pac:
You are silly, again Heinbload a condensing boiler will always produce condense up to the point the return temperature becomes to high,.

Beautiful, we agree then or do you believe all heating systems start above 56c

Iwannahurl

Plombier wrote: »

oldsmokey your own suggestion regarding weather compensation was the most knowledgeable post here, throughout most of the heating season it will serve to keep the return temperature below the condensing temperature of the flue gasses thereby maximising boiler efficiency. Talk to whomever suggested this.

The spelling and punctuation on this webpage could be better, but the content is good I think!

When the combustion products are below their dew point of about 55ºC, the boiler is in condensing mode and it's efficiency increases almost exponentially. Weather compensation is of advantage in systems where high temperature heat emitters such as radiators are used as it allows the system temperature to decrease sufficiently for the boiler to condense.

A boiler which heats radiators and is not fitted with weather compensation will rarely be in condensing mode and will have a much lower seasonal efficiency than a boiler which does. All condensing boilers manufactured by companies such as Immergas and MHG are fitted with weather compensation as standard.

Weather compansation is a very good idea when fitted properly and the hot water flow is not effected by the lower flow temperatures.

heinbloed

Be bright Plombier. And do not use "a sensor" for the house but one for every room. And an intelligent software capeable to learn, capeable to 'understand' interaction.
Ad this to the price and the anual calibration as well.
And get tennants to live according to the software's capeability.

Since there are thousands of weather control units (hundreds of thousands?) installed all over Europe there must be scientific evidence to proofe their influence on fuel consumption.

Sure you have some of this evidence to publish here..... but no sales brochures please, claiming ".. up to x % savings ".

Www. links please, ISBN numbers etc... Black on white.

Plombier

CIBSE Guide H

Building Control Systems

ISBN 07506 504 78

I am actually reading it (hard copy not the internet) at the moment.

You should do the same and learn something.

heinbloed

Iwannahurl posted a text from an advertising:

When the combustion products are below their dew point of about 55ºC, the boiler is in condensing mode and it's efficiency increases almost exponentially. Weather compensation is of advantage in systems where high temperature heat emitters such as radiators are used as it allows the system temperature to decrease sufficiently for the boiler to condense.

A boiler which heats radiators and is not fitted with weather compensation will rarely be in condensing mode and will have a much lower seasonal efficiency than a boiler which does. All condensing boilers manufactured by companies such as Immergas and MHG are fitted with weather compensation as standard.

This refers to a heating system with high return temperatures which is not capeable to cause a condenstion in the boiler.
Thanks again for the link, Iwannahurl.

Only when the return temperature drops to a certain degree condensation can happen, that's what it says in the text. And what many posters here do not understand.

The second part of the advertising however is rubbish:

A boiler which heats radiators and is not fitted with weather compensation will rarely be in condensing mode ....

My boiler has no weather compensation and is always in the condensing modus.
Laws of physics tell us that it is not the weather but the return temperature which causes a standard household condensing boiler to condense. Unless we have outside temperatures above condesing temperature, for methane that is 56 degrees Celsius.....

Meassurements please, hard evidence. No advertisings.

The above text quoted is relevant for a CH system at the brink of condensing efficiency. Not for a CH system which is designed to run efficiently - no matter what the weather is like.
And this is the heating engineer's job.

A sticky plaster on a broken leg - that's what a weather compensation is.

Going back to the original point about to condense or not to condense, I feel condensing gas boilers are fitted to every type of heating system because they have to be and not because it's practical or financial beneficial to do so.


The main benefit of been forced to buy only condensing gas boilers is it's reduced the cost of boilers dramatically and improved the technology neither of which have occurred in the oil industry.

Plombier

The above text quoted is relevant for a CH system at the brink of condensing efficiency. Not for a CH system which is designed to run efficiently - no matter what the weather is like.
And this is the heating engineer's job.

A sticky plaster on a broken leg - that's what a weather compensation is.

The Chartered Institution of Building Services Engineers all disagree with you so maybe you should stop now.

heinbloed

I'm not looking for political texts, Plombier.

We are looking for scientific back-up for your claims.

Hard comparing evidence, numbers collected from at least 1000 researched cases in our climate zone with our building standard. Over 3 years in consequence.

No tea leaf reading.

Plombier

Yes and your scientific back-up for your claims are not to be seen.

heinbloed

Gary71 wrote:

I feel condensing gas boilers are fitted to every type of heating system because they have to be and not because it's practical or financial beneficial to do so.

Try to understand the written word, Gary71. Feelings won't help, it's plain text.
No one is forced to install a condensing boiler when it makes no economical sense. That's Irish law, in writing.
This should be known to a plumber......

heinbloed

heinbloed wrote: »

I'm not looking for political texts, Plombier.

We are looking for scientific back-up for your claims.

Hard comparing evidence, numbers collected from at least 1000 researched cases in our climate zone with our building standard. Over 3 years in consequence.

No tea leaf reading.

You need to get out more;)

Plombier

I'm not looking for political texts, Plombier.

This is far from a political text if you knew anything you would realize its published by one of the most respected institutes in the world.

But only you in all your wisdom could say they are wrong.

heinbloed

Plombier wrote:

Yes and your scientific back-up for your claims are not to be seen.

You do not seem to understand the basic of a discurse, a discussion. Which is in scientific terms thesis versus anti-thesis.

Not Columbus or Gallileus had to prove the world is a flat disc surrounded by the universe. Nor Copernikus.

The prove for this at their time was the pire. Not science.

Bring your arguments and we listen.

And if you can't : ask for back-up, there are plenty of competent installers here who certainly know why they sell these gimmiks. Who do not cheat the consumer, have evidence available. Simply ask, that's what the plumbing forum is about.