Oil supply line - reducing diameter

[DustyM]

Chaps,

I have a customer who's just bought a house and inherited a pretty shabby oil installation i.e. single skinned metal tank (badly corroded), circa 1960's boiler etc. The priority is renewing the tank as I have condemned it, and although ideally he should replace his boiler and the oil supply line at the same time, he cannot afford this. His current installation supplies the oil via an 8mm line, initially surface laid, then it disappears under the house and resurfaces in the kitchen. The new tank he wants me to fit comes with a 10mm outlet and I'd like to run the new supply as close to the house as possible in 10mm before reducing down to the existing 8mm as it enters the house (this is only temporary, as once he has the money for the new boiler I can gain access under the kitchen floor as part of the kitchen refit and fit 10mm all the way to the boiler). Can I reduce the dia of the supply line, and what impact (if any) will it have on the supply pressure (I'm thinking negligible)?

Advice and wisdom welcomed............

 

[Dotty]

Reduce to 8mm at the tank. The oil pump doesn't need to move a large volume of oil and a smaller diameter pipe would actually assist its operation. If, for example, you have a 0.75 nozzle then the boiler would be burning 0.75 US gallons/hr which is 2.84 litres/hr.

 

[peteheat]

Suggest that you have it writing that the installation is temporary and the customer assumes all liability regarding the position of the boiler and the fire valve which I presume is not being replaced at this time.

 

[WHPES]

I fit 8mm as standard for long runs (as recommended in the OFTEC manual). Less susceptible to airlocks, debris and water accumulation.

This is why if you look at the fuel line to your car engine it is tiny, yet it carries a lot more fuel than the oil line.