Interpretation of oil boiler efficiency

[oilboffin]

Tranco very good boiler IMHO just need a good clean every year and resetting make sure the oil pressure is just a little bit under the stated pressure and it'll behave.Bob

 

[oilhead]

If it ain't broke, don't fix it!!!!
You need to buy an awful lot of oil to pay for a new condensing boiler and its installation. You then hope that your system will harvest the benefits of a more efficient boiler.

 

[muggles]

I've just had a service and my 20 year old non condensing oil boiler is running very nicely at 91% net efficiency and 86% gross.

Does this mean the most I stand to gain from a condensing upgrade (in terms of fuel consumption costs) is the difference between 86% and the ~94% gross quoted by Grant and the like in their brochures? Or is the additional heat recovery from the condensing function additional to this?

Thanks

It's not 91% efficient - you/your service engineer are confusing combustion efficiency with thermal efficiency, which is a different thing entirely. A boiler can be burning at 91% efficiency but still throwing 30% of its heat out of the flue rather than putting it into your heating system, thus making it 70% efficient.

Having said that, it's still not going to pay for itself if you have it replaced with a condensing model

 

[Burnerman]

Gentlemen - your expertise please?
When my Panda finally gives up (no 2 port valves, no cylinder stat, gravity HW, as basic as it gets) what are my options?
Panda has 2 flow / returns for CH and HW, hall thermostat controls CH pump. The existing system is cheap enough to run, there's plenty of HW, recovery is fine for the two of us and the cottage is cosy.
So....will I have to have a fully pumped system with a replacement boiler?
The beauty about the Panda is that its only about 300mm wide, and there's not a lot of extra space available without some thought.....the cost isn't a concern, it'll cost what it costs.
Ta for reading!
John

 

[muggles]

Yes, you'll need to go fully pumped @Burnerman, but with all the connections on one side on the new boiler you'll gain enough room I should think. Hounsfield boilers are good and only 350mm wide

 

[Burnerman]

Cheers Andrew, that's what I thought.....I remember Ricky (Boilerman 2) was a great supporter of Hounsfield too so that'll go to the top of the list when the inevitable happens.
I really appreciate your reply
Where is Ricky anyway? A really sound guy.
John

 

[D_Hailsham]

55C is the accepted maximum return temperature for condensing to occur.

The dew point of natural gas is approx 57C; but the dew point of fuel oil is 47C.

 

[oilboffin]

Hounsfield really good boilers they were founded using old boulter engineers and we all know what
good boilers they were,shame Worcester bought them out.Bob

 

[Andy4444]

Cheers Andrew, that's what I thought.....I remember Ricky (Boilerman 2) was a great supporter of Hounsfield too so that'll go to the top of the list when the inevitable happens.
I really appreciate your reply
Where is Ricky anyway? A really sound guy.
John

He's still around! He still posts on the oil forum but not as much as he used to.

Andrew Hounsfield also posts on the forum and is a switched on guy.

 

[garyo]

It's not 91% efficient - you/your service engineer are confusing combustion efficiency with thermal efficiency, which is a different thing entirely. A boiler can be burning at 91% efficiency but still throwing 30% of its heat out of the flue rather than putting it into your heating system, thus making it 70% efficient.

Having said that, it's still not going to pay for itself if you have it replaced with a condensing model

Hence my question. When you get a service sheet quoting 90% its easy to interpret that as there only being 10% of possible gain left. It sounds like its not worth it anyway, unless the oil consumption really would drop by 30%

 

[oilboffin]

Hi andy how can you get on the oil forum sounds interesting.Bob

 

[Andy4444]

Hi andy how can you get on the oil forum sounds interesting.Bob

Hi Bob

Here's the link

http://www.oiltechs.org/forum/index.php

Would be great to see you on there!

Andy

 

[Andy4444]

Bob and Muggles you should have received an email confirming your membership of the forum

Sorry if this is making the thread messy!

 

[oilhead]

If you replace your Panda wit a new boiler, to comply with Building Control regulations and get certified, your system should be brought fully up to date. I wouldn't say this always happens.

 

[oilboffin]

Thanks andy I'm on the forum now.Bob