Boiler Nozzle Size

eamon11

hello Folks,

I added some rads to an old house. The boiler waas not serviced in years so I will be doing that and changing the nozzle. Its a firebird popular 90. I have 13 rads. 2 are very big doubles. However I would only have max 10 at a time on.
What nozzle size do I need? I think its either 0.6 or 0.65. What happens if I use a smaller nozzle? If I had say only 4 rads on would not using a bigger nozzle be less efficient? Doesnt the ultimate heat output depend on the stat setting and not the nozzle size? Does using a bigger nozzle mean burning more fuel? Is this not waste or inefficient?
Sorry but I am confused. Could someone please explain?

Tks in advance,

eamon

Billy Bunting

It would depend on the burner you have on your boiler, if a RDB2.2 your looking at a .65/80oS with a pump presure of 9.5bar, thats manufacturers instructions, but each burner will vary and the only way to set it up to its max efficiency is by using a analyser, guestimating ain't gona do it, recommend you get your Oftec man in.

heinbloed

A heating engineer would be the right person to ask. Ask for an optimisation of the entire heating system. There are more things involved than just the correct size of the boiler.

What happens if I use a smaller nozzle?

The amount of fuel being burned would be smaller, less thermal energy (heat) would be produced in the boiler per hour.

Doesnt the ultimate heat output depend on the stat setting and not the nozzle size?

The thermal output of the boiler depends on the fuel consumption. Nothing else. The heating system is - as the name suggests - a system, every component's performance is depending on the rest of the system.

Does using a bigger nozzle mean burning more fuel?

If the demand side (the thermal distribution = radiators) asks for it - yes.
A smaller nozzle would create less heat, so longer firing times of the boiler can be expected. Therefore fewer on-off situations and less fuel will be consumed.

Is this not waste or inefficient?

It depends on the heating system: if the boiler goes on for several times per hour it would use more fuel as if it was running smothly over the entire hour.
Most boilers are severly oversized, as a rule of thumb a smaller nozzle/boiler capacity would suit better most householder's pockets.

How is the boiler performing at the moment? Is it running in a pendular mode, on and off permanently? If yes then it's output is oversized. Reducing it's maximum capacity by feeding it less fuel would then certainly save fuel.

A modulating condensing boiler could be a good long-term investment. Again: ask a heating engineer who would give you a calculation in writing.

DGOBS

Reducing a nozzle below the design input of the boiler would increase fuel usage and lead to an inefficient appliance.

I agree most boilers are oversized

Modulating condensing OIL boiler??? Domestic ???
A furnace maybe!

heinbloed

DGOBS wrote:

Reducing a nozzle below the design input of the boiler would increase fuel usage and lead to an inefficient appliance

Please explain this.

Modulating condensing OIL boiler??? Domestic ???

Well, if we know where to shop....see previous threads. If you need manufacturer's adresses and sale points for modulating condensing oil boilers (household size) - ask.
Poster Gary71 might be able to help as well ....

Billy Bunting

Here he goes again!!

Amazing what you can find on the Intenet in Heinbloed world. :rolleyes:

Get real!! the OP just want to heat his 4 little rads cheaply.

heinbloed

Oftec members simply know more:

http://www.directoil.co.uk/news/heating-oil-news/Non-modulating-oil-boilers-are-no-less-efficient.aspx

and

http://www.dunravensystems.com/?p=1

Oftec struggles to keep modulating condensing boilers out of reach.
Spreading rumours like that condensing modulating oil boilers aren't more efficient than non-modulating ones.
What an organisation!

And what members who tolerate something like that.

The modulating condensing oil boiler

...could threaten the future of the oil heating industry throughout the British Isles.

Almighty. Being trained with the aid of a major climate killing company (oops, climate change doesn't exist according to Chevron !) to use less home heating oil - that really can't be, could it. I mean that could threaten the future of Chevron.

Welcome to the Chevron school of biased ignorance:

http://www.chevrontraining.ie/oilboilercourses/index.html

heinbloed

Maybe Billy Bunting could explain to us why a reduction of the nozzle size would increase the oil consumption - as claimed by DGOBS.

I really haven't got a clue. Honestly.

Thanks.

Billy Bunting

heinbloed wrote: »

I really haven't got a clue. Honestly.

.

Try the intenet Oftec Technical book 1 will give you a starter. :rolleyes:

heinbloed

heinbloed wrote: »

Poster Gary71 might be able to help as well ....

Tony(DGOBS) you know that saying a little bit of knowledge is a dangerous thing, well meet Heinbloed, reads a lot(more than me:o) but has no practical experience to assist him in developing his DIY theory's, this can lead to him making silly statement of fact:pac:. as for modulating oil boilers Viessmann do one as do other manufactures but they have no plans to bring them to Ireland.

Micky Dolenz

OP, it may be a good investment to have a pro commission/service your boiler. Unless you have a oil pressure gauge and flue gas analyser, it's a bit hit and miss. There is more to a service then changing a jet and cleaning the boiler.

Burner pressure and nozzle size determine heat output. Once these are changed, air intake must also be changed.

DGOBS

What I mean about reducing the nozzle size too far....

Imagine, you have a forty foot trailer (your heating load) and you hitch it up to your 1 litre Toyota yards and try drag it up a hill, the fuel you would need to expend would be greater than hitching it to a lorry.

So if your burner input is too low for the boiler, it will struggle to heat the appliance as designed, not a perfect analogy but close enough to see the point

With and non-modulating appliance, gas or oil, lower the input to the lower design range of the appliance and watch the efficiency slowly fall away on a flue gas analyser (gas is worse as the excess air level increases, at least you can adjust this with oil)

Gary, didn't realise the Viesmann oil boiler was modulating, and haven't seen anything from the likes of Riello or Nu-Way that modulates domestic, G series Riello do when you get up to G20 and the likes, which would be non-domestic (ie over 45kw input)

I don't see how Oftec could keep any appliance out of reach?
There is no requirement for any appliance to have an Ofcert?

Stephen Grant IMHO is one of the best boiler designers I have ever met, and he seems to feel that the boilers that they have on the market at the minute have reached the maximum theoretical efficiency limit, and if modulation was seen as a major gain here, I have no doubt that his company would be pursuing it! (and I will ask the question the next time I see him)

JohnnieK

DGOBS wrote: »

Stephen Grant IMHO is one of the best boiler designers I have ever met, and he seems to feel that the boilers that they have on the market at the minute have reached the maximum theoretical efficiency limit, and if modulation was seen as a major gain here, I have no doubt that his company would be pursuing it! (and I will ask the question the next time I see him)

I was very impressed with GRANT when I was down there. They explained there products very well and to be honest there all I install in relation to oil boilers. I'm looking forward to there condensing pellet boiler, they where testing it when I was down there so It could be on the market by now.

DGOBS

It is available now

heinbloed

Contact the Irish manufacturer of this condensing pellet boiler to get his equipment into this test result list, the market is waiting for more competition:

http://blt.josephinum.at/index.php?id=331

Oekofen seems to be the only one so far

http://www.oekofen.co.uk/en/products/pellematic-smart.html

Any link to this Irish condensing pellet boiler?

DGOBS

Grant Engineering are the manufacturer, not sure if it's on the website (assume it is)

Don't think you'll like him though (a founding member of Oftec!)

heinbloed

http://www.grantengineering.ie/product-area/grant-wood-pellet-boiler/

kscobie

They are only selling that boiler to installers who have done the course in the factoty, and passed the assessments. I done the course 2 months ago, and honestly think this is the bees knees, d guy who gave the training said they spent 2 years on R&D for the Vortex, and 4 years on the woodpellet boiler, enough said.

heinbloed

They are only selling that boiler to installers who have done the course in the factoty, and passed the assessments.

Imagine a car manufacturer would sell his cars under these conditions - no chance.
I wonder why a global player like Oekofen does not use these contract terms?
Their products (incl. condensing pellet boilers) can be purchased and installed on a global scale, ebay etc...see the top right corner under ' languages '

http://www.oekofen.co.uk/en/products/pellematic-smart.html

Is the grant technology to complicated?

Thanks.


PS

Correction:

Above I stated:

"Oekofen ..... products (incl. condensing pellet boilers) can be purchased ....(on) ebay"

This is correct for second-hand boilers of this brand but not for new boilers ex-factory. Sorry for any misunderstandings.

kscobie

No, its actually quiet simple and straight forward, so is the pipework, flow, return, condensate trap and 1/2" water mains for the auto wash on the condensing unit, no buffer tank, no mixing valves, years ahead of the Opop i fitted years ago. And its red......:)

heinbloed

Thanks, kscobie.

Is there a technical data sheet available on-line? I've tried the link provided and there is a lot of material for the other Grant products but I couldn't any Spira details.