# Home oil: What is "light oil"?



## javapie (27 Aug 2011)

Hi,

Recently moved into a rented house with central oil heating. I have no idea what type of heating oil to buy (gas oil or kerosene?) and landlord doesn't seem to know either.

The oil burner, a Riello 40 states "light oil", but I can't find which one (gas oil or kerosene) that corresponds to. The oil boiler is from Ferioli in the 1970s and is outside in the garage....

Anyone know off hand? Thanks in advance.


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## hastalavista (27 Aug 2011)

IMO get landlord or letting agent to tell u : u get it wrong u will pay for the subsequent mess: u cannot trust the label


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## Shane007 (27 Aug 2011)

Check the colour of the fuel. If it is red, it is kerosene and if it is clear, it is gas oil.

Generally, light oil refers to gas oil, however, if could well have been changed to kerosene so it is best to check the colour of the fuel.

Easiest way to check is to unscrew the bottom of the filter bowl to expose the fuel within it.


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## ACA (27 Aug 2011)

Is there no old sticker from an oil supplier? I had no idea what type of fuel to get... my local supplier put me right


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## computerman (28 Aug 2011)

Try to wait at least another 2 weeks before buying heating oil. Oil is dropping on the international markets but has not yet been sufficiently reflected on the retail market here YET


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## roker (29 Aug 2011)

Generally an oil boiler has a flue going to a high level, a kerosene boiler has a low level flue usually near the boiler


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## Shane007 (29 Aug 2011)

roker said:


> Generally an oil boiler has a flue going to a high level, a kerosene boiler has a low level flue usually near the boiler


 
Sorry but that is not true. All burners can run on both gas oil and kerosene. Gas oil being a heavier fuel than kerosene and therefore requires a higher oil pump pressure to atomize the fuel in order for air to completely surround all of the fuel for a clean burn and to avoid incomplete combustion.

It only variant is that condensing boilers should only be run on kerosene.

The only way to guarantee what type of fuel to use to physically look at the colour of the fuel or if the oil tank is empty, fill with kerosene and have an OFTEC engineer adjust the burner settings to suit. He could be service the boiler and set up a nice clean and efficient burn just in time for a nice harse winter!


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## javapie (29 Aug 2011)

Thanks for all the suggestions.

I checked the oil colour and it was light green. I think this is "green diesel" or gas oil, definitely not red.

I also rang a supplier mentioned by the LL, and they confirmed a previous delivery of gas oil.

So it seems, in this case, "light oil" is Irish "gas oil".

I'm using cheapestoil.ie to keep an eye on Irish oil prices, and may arrange an OFTEC service also since the boiler/burner seem really old.

Thanks again.


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## Shane007 (29 Aug 2011)

If your oil level is empty, it is cheaper and more efficient to run on kerosene. During cold weather, gas oil becomes waxy and is harder for atomize and therefore incomplete combustion occurs resulting in a sootier boiler. Kerosene can withstand much lower temperatures before waxing occurs.


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## roker (30 Aug 2011)

Shane0078,  I stand corrected on that, that is just my own observation, I have never seen a low level flue for gas oil, i thought the fumes had to be taken away.


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## Shane007 (30 Aug 2011)

roker said:


> Shane0078, I stand corrected on that, that is just my own observation, I have never seen a low level flue for gas oil, i thought the fumes had to be taken away.


 
No worries. I can see how you have come to that conclusion, as most older boilers would have been run on gas oil and traditionally flue terminals were at high level. More recent standard efficiency boilers changed to kerosene and at the same time the low level balanced flue was born. This is where the air intake is fed from the outside directly to the burner and having it not dependent on competing for air internally with other household appliances such as tumble driers, extractor fans, etc. Balanced flues normally have their air intake built into the surround of the flue terminal externally and at low level.

Flue terminal locations are governed by site conditions rather than fuel type, i.e. proximity to openings, walkways, etc. All fuel types must have their flue gases "taken away" but as long as they meet Building Regulations as in minimum distances kept from openings, air bricks, boundaries, eaves, not under car ports, etc., both fuel types can be discharged at most levels up to a certain maximum height (determined by the individual manufacturer). Other criterias also apply but not necessary to go into here.

Gas oil & kerosene have very similar characteristics and burn equally as well except for gas oil requires more pump pressure to fully atomize the fuel into vapour and behaves different under colder conditions. All other characteristics after combustion are identical as long as full combustion has been achieved.


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