condensing vs non condensing oil efficiancy

corkgsxr

Right let's say you have a decent running firebird popular 90 boiler 10 years old.

Upgrade to a firebird/grant condensing boiler.

What would you expect the saving to be.

I'd say about 10% best case, unless the boiler your replacing is a heap

A lady I'm quoting got told around 30% saving.

What you recon

cikearney

I dont think there is that much to be saved upgrading oil boiler, unless it's a heap of course, especially not 30%

But if your lead to believe the ads on the telly and the leaflets in the door, this is what you get

What about the power flusher guy who will increase the eff of your heating by 40%, What is it again "don't upgrade................."

But what if you have an ideal classic 19 years on the wall hasn't been service in 5/6 years still running, you could expect 30/35% saving easily with most HE boilers on offer

spireland32

Old: 75-78% New: 92% approx To achieve 20%-30% you need to upgrade the heating controls. Room stats and cylinder stat controled by electric valves with full boiler interlock. And on top of you really need some type of insulation in the house... to keep the heat in and keep the stats satisfied and keep the boiler off as long as possible.

cikearney

But that is achieved by upgrading your heating system AND boiler. What if you were to install all of the above, give the boiler a service and tune the burner so it is running correctly, I'd say it'd be very close without the cost, given that the boiler in question is in pwo and is/was a high quality product

corkgsxr

spireland32 wrote: »

Old: 75-78% New: 92% approx To achieve 20%-30% you need to upgrade the heating controls. Room stats and cylinder stat controled by electric valves with full boiler interlock. And on top of you really need some type of insulation in the house... to keep the heat in and keep the stats satisfied and keep the boiler off as long as possible.

Upgrading heating controls would increase how efficiently you use your heat but it hasn't the slightest on boiler efficiency.

Boiler efficiency is what percentage of the heat is transfered to the water and what % goes out the flue.

shane0007

corkgsxr wrote: »

Right let's say you have a decent running firebird popular 90 boiler 10 years old.

Upgrade to a firebird/grant condensing boiler.

What would you expect the saving to be.

I'd say about 10% best case, unless the boiler your replacing is a heap

A lady I'm quoting got told around 30% saving.

What you recon

You need to consider both combustion efficiency and seasonal efficiency to compare properly.
A Grant Vortex being the most efficient so it is best to use this as the benchmark. A bit less for others.
Combustion efficiency will be in or around 99% efficient.
35kw is 97% & 26kw is 95% seasonal efficicency. These are now going to be dropped by SEDBUK to force manufacturers to make further improvements,

Firebird Popular, 10 years old circa, if looked after and properly serviced over the years will probably have a combustion efficiency of in or around 80 - 83% while its season efficiency will be around 78%.

It can be concluded that an average of 16 - 19% saving can be made from just a boiler swap over.

Have a look at the flue gas temperatures as this will give an accurate indication of the condition of the boiler. When the Popular was new it would have had flue temperatures of circa 180 - 200C. As it ages, the metal suffers from fatigue and becomes more difficult to transfer the heat from the flame chamber into the heating system and as this happens, the FG temps rise, wasting more useful heat and fuel to atmosphere.
With the Vortex, you will find FG temps of 45 - 60C, so the savings are clear. The heat from the 1,100C flame chamber temp is very successful at transferring all but approx 1% of this useful heat into the heating system and wasted to atmosphere.

corkgsxr

shane0007 wrote: »

You need to consider both combustion efficiency and seasonal efficiency to compare properly.
A Grant Vortex being the most efficient so it is best to use this as the benchmark. A bit less for others.
Combustion efficiency will be in or around 99% efficient.
35kw is 97% & 26kw is 95% seasonal efficicency. These are now going to be dropped by SEDBUK to force manufacturers to make further improvements,

Firebird Popular, 10 years old circa, if looked after and properly serviced over the years will probably have a combustion efficiency of in or around 80 - 83% while its season efficiency will be around 78%.

It can be concluded that an average of 16 - 19% saving can be made from just a boiler swap over.

Have a look at the flue gas temperatures as this will give an accurate indication of the condition of the boiler. When the Popular was new it would have had flue temperatures of circa 180 - 200C. As it ages, the metal suffers from fatigue and becomes more difficult to transfer the heat from the flame chamber into the heating system and as this happens, the FG temps rise, wasting more useful heat and fuel to atmosphere.
With the Vortex, you will find FG temps of 45 - 60C, so the savings are clear. The heat from the 1,100C flame chamber temp is very successful at transferring all but approx 1% of this useful heat into the heating system and wasted to atmosphere.

Are ya mad 99% efficient even grant only claim 93.3% running most are about 90% no more.

If they were that efficient there'd be noone with a gas boiler

shane0007

You are confusing combustion efficiency with SEDBUK efficiency. Have you never used a FGA.
A HE gas boiler will also have a combustion efficiency of circa 99% but a SEDBUK efficiency of 90.2% mostly.

shane0007

corkgsxr wrote: »

Are ya mad

Many say I am, but as yet it is only a rumour.

corkgsxr

shane0007 wrote: »

You are confusing combustion efficiency with SEDBUK efficiency. Have you never used a FGA.
A HE gas boiler will also have a combustion efficiency of circa 99% but a SEDBUK efficiency of 90.2% mostly.

I have used a fga, but make sure your on the right setting, wrong setting with a fga on a gas boiler you can get efficiencies of 120%.

No way is a oil boiler more than 90% efficient.

shane0007

120%!!!! What settings are you using to see that. Even Net HE would not give more than 102% and that if the return temp is below 35C. Have you even got the boiler upto operating temperature?

Ring Grant 057 - 9120089 in the morning, ask to speak to their Technical Department, Keith Scully and ask him what COMBUSTION Efficiency would you expect to see from a Grant Vortex. Also ask him what is the SEASONAL Efficiency of same boiler. If you do not believe him, then ring Firebird 026 - 45253 and ask their Technical Department, Brendan Toomey, the same question for the Firebird Environmax. The answer will be a couple of percentage points below the Vortex.

shane0007

Also go to www.boilers.org.uk
Click on "View the boiler efficiency database" button.
Then click Oil Boiler button on bottom right of page.
You will then see that Vortex is SAP 2005 97% and SAP 2009 is 93.3%.
So they have already downgraded the efficiency to force the manufacturers to improve.
This is SEASONAL EFFICIENCY, which is net after losses through boiler casing, fittings etc.
Combustiin efficiency is in relation to the calorific value of the fuel being used and in relation to FG temps. This is why it is of great importance before carry out a FGA that the correct fuel is selected on the Analyiser.

WestWicklow1

corkgsxr wrote: »

Right let's say you have a decent running firebird popular 90 boiler 10 years old.

Upgrade to a firebird/grant condensing boiler.

What would you expect the saving to be.

I'd say about 10% best case, unless the boiler your replacing is a heap

A lady I'm quoting got told around 30% saving.

What you recon

I did it three years ago and doubled the amount of insulation in the attic at the same time.

Over those three years I have used the same amount of oil as I always did. It was a complete waste of a lot of money. I was completely taken in by the adverts and the installer.

I have now installed this....

running on pea/rice coal (but will take any soild fuel)....

jimf

shane0007 wrote: »

You need to consider both combustion efficiency and seasonal efficiency to compare properly.
A Grant Vortex being the most efficient so it is best to use this as the benchmark. A bit less for others.
Combustion efficiency will be in or around 99% efficient.
35kw is 97% & 26kw is 95% seasonal efficicency. These are now going to be dropped by SEDBUK to force manufacturers to make further improvements,

Firebird Popular, 10 years old circa, if looked after and properly serviced over the years will probably have a combustion efficiency of in or around 80 - 83% while its season efficiency will be around 78%.

It can be concluded that an average of 16 - 19% saving can be made from just a boiler swap over.

Have a look at the flue gas temperatures as this will give an accurate indication of the condition of the boiler. When the Popular was new it would have had flue temperatures of circa 180 - 200C. As it ages, the metal suffers from fatigue and becomes more difficult to transfer the heat from the flame chamber into the heating system and as this happens, the FG temps rise, wasting more useful heat and fuel to atmosphere.
With the Vortex, you will find FG temps of 45 - 60C, so the savings are clear. The heat from the 1,100C flame chamber temp is very successful at transferring all but approx 1% of this useful heat into the heating system and wasted to atmosphere.

have to agree 100% here with you shane recently serviced and fga a popular 90 set up to what i would say is spot on fga wise but flue temp is the problem
298c is as low as i can get it just cant transfer its heat because of metal fatigue baffles good flueway good so its had its day only used about 10/12 hours a week so not really not worth changing

but a very good and valid point often overlooked flue temp can tell a story

kscobie

Was at a customer last week, replaced a 12 year old warmflow 90 with a Vortex this time last year, he was using 2 tanks (1000ltr) of kero a year, so far has only used 1 and a half tanks, he is happy..., and now i have to replace his neighbours cast iron Sime, now i'm happy

jimf

kscobie wrote: »

Was at a customer last week, replaced a 12 year old warmflow 90 with a Vortex this time last year, he was using 2 tanks (1000ltr) of kero a year, so far has only used 1 and a half tanks, he is happy..., and now i have to replace his neighbours cast iron Sime, now i'm happy

good for you

see the old word of mouth is the best advertising

shane0007

WestWicklow1 wrote: »

I did it three years ago and doubled the amount of insulation in the attic at the same time.

Over those three years I have used the same amount of oil as I always did. It was a complete waste of a lot of money. I was completely taken in by the adverts and the installer.

I have now installed this....

running on pea/rice coal (but will take any soild fuel)....

Impossible! Even if the boiler was incorrectly set up and even if it never got into condensing mode, it would have used less oil. Either your statement is untrue or something else was going on with the system.

JohnnieK

shane0007 wrote: »

Impossible! Even if the boiler was incorrectly set up and even if it never got into condensing mode, it would have used less oil. Either your statement is untrue or something else was going on with the system.

I've done probably 8 oil upgrades over the last two and a half years and they are all happy with there oil usage. I think something could be wrong some where with that installation.

dathi

one of the problems with any energy upgrade is that the home owners usage pattern changes and the expected savings do not materialize . in other words when you have an old boiler that guzzles oil you only have it on for a few hours a day,then when you switch to modern boiler you think you are going to use less oil so you leave it on for longer each day there by using the same amount of oil. the answer to this is to fit proper controls. ie room stats that can call for heat and turn off boiler when temp has reached the pre set level even if the time clock is calling for boiler on.done this to my own system and left the 15 year old boiler in place. that with improvements to insulation has cut 1000 ltr of kerro per year of usage and house is toasty .

DGOBS

I find a lot of the time installers are still over sizing boilers, a condensing boilers need to be correctly sized and set up as close to a 20deg differential to realize the savings, with a low flow temp. (closer to 60deg that 70-80!)

Seen one 35kw, 15 yards from the house, which maybe only needed a 26kw boiler, it cycled so often that fuel usage was pretty much the same a the old boiler

I changed my own SE oil boiler 8 years old, ranged to 110k but, to a 90btu ranged at 80k but, heats the house within 15-20 mins on first cycle, have used approx 50% the fuel I used for same period last year.

corkgsxr

True, oversizeing is completely wrong for condensing oil.

But saying that once temp goes over 50 ish degrees preheating effect of the second chamber is gone.

To run a condensing boiler to max efficiency it needs to run at about 40 degrees, but you can't do that with ours because there only stainless in the second chamber, and if the temp drops to low they rot to pieces.

But fully stainless would last to long so the won't supply them here

DGOBS

I disagree with that totally, flue gas temperature would still not exceed 80 degrees, which is still a 10% increase in efficiency over a standard boiler.
What gets over looked is the fact a condensing boiler having a secondary heat exchanger in creases the total surface area capable of conducting flue gas heat into to water, it may even stop condensing, but remains more thermally efficient.

One proof of this is the fact that manufacturers can use thermoplastic flues these days.

There is fully stainless steel oil boilers readily available if you want them, I service a number of them regularly

corkgsxr

DGOBS wrote: »

I disagree with that totally, flue gas temperature would still not exceed 80 degrees, which is still a 10% increase in efficiency over a standard boiler.
What gets over looked is the fact a condensing boiler having a secondary heat exchanger in creases the total surface area capable of conducting flue gas heat into to water, it may even stop condensing, but remains more thermally efficient.

One proof of this is the fact that manufacturers can use thermoplastic flues these days.

There is fully stainless steel oil boilers readily available if you want them, I service a number of them regularly

At what price? Last I looked they were extortionate.

My point is maximum efficiency. I agree there about 10% better.

But warmer the boiler gets the less efficient it gets. We have to put large enough bypasses to keep return temp higher to stop the boiler rotting, which makes them less efficient. A total stainless boiler needs no bypass apart from pressure based for the pump

Dardania

DGOBS wrote: »

I find a lot of the time installers are still over sizing boilers, a condensing boilers need to be correctly sized and set up as close to a 20deg differential to realize the savings, with a low flow temp. (closer to 60deg that 70-80!)

Seen one 35kw, 15 yards from the house, which maybe only needed a 26kw boiler, it cycled so often that fuel usage was pretty much the same a the old boiler

I changed my own SE oil boiler 8 years old, ranged to 110k but, to a 90btu ranged at 80k but, heats the house within 15-20 mins on first cycle, have used approx 50% the fuel I used for same period last year.

Completely agree with the above. And also would like to add, when choosing a boiler, you should check what the minimum output it can modulate down to... Presuming you have TRVs etc. that close off when they are satisfied, if the boielr can modulate down low, you can heat the alst room nicely...

WestWicklow1

shane0007 wrote: »

Impossible! Even if the boiler was incorrectly set up and even if it never got into condensing mode, it would have used less oil. Either your statement is untrue or something else was going on with the system.

3000 litres of diesel every year before boiler change. 3000 litres of kerosene every year since boiler change. Same usage, same controls, more attic insulation with new boiler.

My statement in my last post is not untrue.

Dardania

WestWicklow1 wrote: »

3000 litres of diesel every year before boiler change. 3000 litres of kerosene every year since boiler change. Same usage, same controls, more attic insulation with new boiler.

My statement in my last post is not untrue.

Diesel and kerosene have slightly different energy factors: http://www.seai.ie/Your_Business/Public_Sector/FAQ/Energy_Reporting_Overview/What_units_do_we_use_to_submit_energy_data_What_are_the_conversion_factors_used_.html - maybe that's a factor?

Also, with condensing boilers, you only see the efficiency jump if you lower the return temp - see this graph: http://www.rvr.ie/Advice/Specifiers/Weather_Compensation/ . To achieve this, you need to rebalanceyour heating system for a 20c delta t (as opposed to the traditonal 10C) and set you output temp at 70C (as opposed to 80C). It also helps if you have weather compesnation to further reduce the flow temp

DGOBS

West wicklow, something doesn't add up though, how often does the boiler cycle.

Darnia, these domestic oil boilers do not modulate (at all)

Corkgsxr, do the math, combustion temp of 1100ºc, SE boilers roughly 200-220ºc to atmosphere, even with a house maxed out you still won't see a flue gas temp of over 80ºc on a condensing boiler, your still at 10% better worst case!
As for condensing in the steel part of the boiler, haven't seen it yet (and I do this all day every day) and to include your bypass is only a waste of energy. Remember, the cool return water meets the condensing heat exchanger FIRST, by the time it reaches the ferrus section of the boiler it will have risen above 55ºc and no condensing takes place there, it's what is know as 'designed for purpose'

On one hand you complain that the boilers should be made completely of stainless steel, then complain about the cost of the boilers that have only the secondary exchanger made from stainless (done to keep the cost down) you can't have it both ways my friend.

corkgsxr

DGOBS wrote: »

West wicklow, something doesn't add up though, how often does the boiler cycle.

Darnia, these domestic oil boilers do not modulate (at all)

Corkgsxr, do the math, combustion temp of 1100ºc, SE boilers roughly 200-220ºc to atmosphere, even with a house maxed out you still won't see a flue gas temp of over 80ºc on a condensing boiler, your still at 10% better worst case!
As for condensing in the steel part of the boiler, haven't seen it yet (and I do this all day every day) and to include your bypass is only a waste of energy. Remember, the cool return water meets the condensing heat exchanger FIRST, by the time it reaches the ferrus section of the boiler it will have risen above 55ºc and no condensing takes place there, it's what is know as 'designed for purpose'

On one hand you complain that the boilers should be made completely of stainless steel, then complain about the cost of the boilers that have only the secondary exchanger made from stainless (done to keep the cost down) you can't have it both ways my friend.[/QUl


What about the massive amount of firebird boilers that were returned over primary heat exchanger rotting?

I complain about us being massively over. Charged for fully stainless boilers.

shane0007

corkgsxr wrote: »

What about the massive amount of firebird boilers that were returned over primary heat exchanger rotting?

I complain about us being massively over. Charged for fully stainless boilers.

That was not the issue. It was because they were not using 316 at the beginning!

corkgsxr

shane0007 wrote: »

That was not the issue. It was because they were not using 316 at the beginning!

What we're they using?

corkgsxr

DGOBS wrote: »

West wicklow, something doesn't add up though, how often does the boiler cycle.

Darnia, these domestic oil boilers do not modulate (at all)

Corkgsxr, do the math, combustion temp of 1100ºc, SE boilers roughly 200-220ºc to atmosphere, even with a house maxed out you still won't see a flue gas temp of over 80ºc on a condensing boiler, your still at 10% better worst case!
As for condensing in the steel part of the boiler, haven't seen it yet (and I do this all day every day) and to include your bypass is only a waste of energy. Remember, the cool return water meets the condensing heat exchanger FIRST, by the time it reaches the ferrus section of the boiler it will have risen above 55ºc and no condensing takes place there, it's what is know as 'designed for purpose'

On one hand you complain that the boilers should be made completely of stainless steel, then complain about the cost of the boilers that have only the secondary exchanger made from stainless (done to keep the cost down) you can't have it both ways my friend.

I'll try this again, was pissed last night

No my point is were being massively overcharged for fully stainless boilers.

And I sed already its about 10% saving but no more than that

I think you have to include a bypass, iv sent back 3 firebirds over the heat exchangers rotting. Heat merchants told me a fortune had been sent back. I was told return temp had to be hotter.

DGOBS

Stainless steel is graded for purity, 316 being the highest grade as it has no ferrus material, they originally used 304 stainless which is lower grade.

Even processing stainless steel can be an issue, as if for example a cutting blade was used for mailed steel, then later for cutting stainless it would actually impregnate the stainless at the cut edge with ferrus material that can lead to rusting and failure of a weld/joint etc.

And in fairness to firebird they have held their hands up and admitted there was an issue.

shane0007

DGOBS wrote: »

Stainless steel is graded for purity, 316 being the highest grade as it has no ferrus material, they originally used 304 stainless which is lower grade.

Even processing stainless steel can be an issue, as if for example a cutting blade was used for mailed steel, then later for cutting stainless it would actually impregnate the stainless at the cut edge with ferrus material that can lead to rusting and failure of a weld/joint etc.

And in fairness to firebird they have held their hands up and admitted there was an issue.

You answered my reply!

corkgsxr

DGOBS wrote: »

Stainless steel is graded for purity, 316 being the highest grade as it has no ferrus material, they originally used 304 stainless which is lower grade.

Even processing stainless steel can be an issue, as if for example a cutting blade was used for mailed steel, then later for cutting stainless it would actually impregnate the stainless at the cut edge with ferrus material that can lead to rusting and failure of a weld/joint etc.

And in fairness to firebird they have held their hands up and admitted there was an issue.

I know stainless grades, and unless there were using a atrocious quality 304 it shouldn't be a problem, yes 316 is higher resistance to acids but 304 is fine for the job. 316 won't stain as easy or mark over heat. And cross contamination with mild steel will cause surface rusting.

If that's there reason there's something wrong there

corkgsxr

Anyway it wasn't the stainless part that went, it was the primary mild steel part

corkgsxr

DGOBS wrote: »

West wicklow, something doesn't add up though, how often does the boiler cycle.

Darnia, these domestic oil boilers do not modulate (at all)

Corkgsxr, do the math, combustion temp of 1100ºc, SE boilers roughly 200-220ºc to atmosphere, even with a house maxed out you still won't see a flue gas temp of over 80ºc on a condensing boiler, your still at 10% better worst case!
As for condensing in the steel part of the boiler, haven't seen it yet (and I do this all day every day) and to include your bypass is only a waste of energy. Remember, the cool return water meets the condensing heat exchanger FIRST, by the time it reaches the ferrus section of the boiler it will have risen above 55ºc and no condensing takes place there, it's what is know as 'designed for purpose'

On one hand you complain that the boilers should be made completely of stainless steel, then complain about the cost of the boilers that have only the secondary exchanger made from stainless (done to keep the cost down) you can't have it both ways my friend.

Looked it up, both firebird and grant say when the boiler is at operating temperature the return must not be less than 40 degrees and your warranty is invalid if it turns out damage was caused by return temps too low

shane0007

corkgsxr wrote: »

Looked it up, both firebird and grant say when the boiler is at operating temperature the return must not be less than 40 degrees and your warranty is invalid if it turns out damage was caused by return temps too low

And your point is?

If a system is properly designed and installed, it should have a delta T of 20C for HE boilers. This would give a circa 55C return. This can be maintained with properly sized radiators and a modulating circulating pump.

304 stainless steel is not suitable for the secondary heat exchanger as the acidity surrounding that just simply eats it. It is why Firebird learned an expensive lesson.

DGOBS

Who was talking about return temps below 40ºc?
As I suggested, the work best at 60ºc flow, 20º differential
and what your suggesting about condensing in the primary heat exchanger at this and above does not occur, so why install an open inefficient bypass? it's a nonsense (as is this thread is becoming)

Shane, after working in boiler manufacture, and fabrication industry for over 15 years, you are 100% correct about 304
(316 was always commonly referred to as 'kitchen grade')

It would be about 10% more efficient 'worst case' when the house is at temperature, as I said never seen a flue gas temp over 80deg on them in that situation, so thats estimated 130degs (of 1100) more heading into the house than to the atmosphere (over 10%) with low return temps flue gas is about 50degs so thats 160degs saved.

But, hey, I am sure you know best, will ring Steven Grant on Monday, and tell him to close the doors, there is no point in what he's doing, someone here told me so.

lpmurphy

Hi WestWicklow1 - what is the boiler you're using? Could you post more info pls? I'd be very interested in that!