LPG Gas jet sizing

My Gauge 1 gas fired loco was running well until the gas jet, marked "10" became blocked again and again. I replaced it with a new gas jet marked "8" from my usual supplier, expecting perhaps a small loss in heat output. What I did get was a gas overload - great difficulty in lighting the ceramic burner and gas burning at the chimney even when the burner was alight. On inspecting number "8" it was clear that the orifice of the jet was much larger than the orifice of the number "10" jet. In general jet orifice sizes increase with the jet number but my limited research has discovered that different manufacturers eg blowlamp, camping stuff, LPG fires etc apparently use different jetting numbers. Does anyone know of a jet comparison/ cross reference/application type of chart that might throw some light onto this murky area?

Mick

Sorry I can't help, but I do know that jet sizes refer to the quantity of fluid that can flow under given conditions. So I guess that the conditions are different for the makers ?

Mick it might be worth asking on the 16mm narrow gauge modelling Yahoo group. I know there has been discussion of gas jet sizes and alternatives on there earlier this year. Keith

Thanks gents. I will have a look at the 16mm site.

Mick

I have had a look at the 16mm site and it is my impression that the correspondents are similarly searching in the dark. One post mentioned correct burner/jet design as being desirable if not essential but it went no further on detail. I feel that I now need to go back to basics and tackle this burner/jet design thing. Where to start? That is the question.

Mick

Carburetter jets ? There is the SU manual .Burlen fuel systems . Worth a try

Maurice.

Hi Folks,

Although I cannot, personally, vouch for these sizes they came from a good source, Mike the former MaccSteam boiler maker now retired

The sizes are Number 3 has 0.15 mm jet bore

Number 5 has 0..2mm jet bore

Number 8 has 0.25mm jet bore

Number10 has 0.277mm jet bore

Number 12 has 0.3mm jet bore

Number 16 has 0.35mm jet bore

I hope that will add some more to the general information source

All the best Fred Graham

The first one should be 0.2mm not 0..2

Fred Graham

Hi Folks,

Does anyone know who supplies jets for burners as most of the suppliers of boilers and burners do not seem to.

I found one the does called 'Maidstone Engineering Supplies' but there must be others. Someone mentioned a 'Usual supplier ' Who might that be?

All the best, Fred Graham

May give Forest Classics a call link

https://www.forest-classics.co.uk/

No connection

H

Hi Harry,

Thank you for the Link but they don't seem to sell Jets. I tried there 'search bar' and it came back as not recognised, so it look like another supplier not stocking them, which Is surprising.

I will contact them again and see f I can get a clear 'yes or no' response.

All the best, Fred Graham

Not sure how much exploring you did but if you had scrolled down to the bottom of the page you would have seen a link to the page you need - gas essentials and jets

Roger

Hi Harry,

Try looking on the 16mm web site on the 'resources' pages. You could also try Anything Narrow Gauge, Chuffed to Bits, Roundhouse Engineering or possibly Garden Railway Specialists. If they cannot help they may be able to point you in the right direction. Might also be worth contacting Polly Models.

Hope this helps,

Iain

Seeking advice from the supplier(s), after accurately describing the problem experienced, would be my course of action.

Hi folks,

Thanks for comments and especially Roger, OOPs did not notice that link on Forrest Classics, What a plonker!

Lost inside a paper bag and can't find the way out and poor explorer, to boot. Thanks again for keeping me right.

They seem to have a good range and reasonably priced too!

All the best, Fred

You can re-size a jet if it is made of brass.

Buy yourself a set of Swiss Broaches typical brands BERGEON No 1896 They are a bit pricey, but you may find some on various auction sites.