KBB fire valve size

[Avocet]

We have an oil-fired boiler that packed up today. Th problem was a lack of fuel. It seems the KBB fire valve was preventing the oil from getting through.

I gues I need to replace it? It's been there fore 20 years. I was just wondering about sizes. When they list tthem as "1/4" are they referring to the BORE of the pipes that feed it? I have some copper pipes going in and out of it, these are about 5/16" on their OUTSIDE diameter, so I'm wondering what size of valve I need to order.

 

[PullerGas]

If it has Female threads then the 1/4" is BSP. If it's only 20 years old there's every chance it's 10mm copper tube.

 

[simond]

When you say it seems like, had it tripped? Can it be manually opened again?

 

[Andy4444]

Usually get KBB in 1/4 BSP If you have a 10mm oil line (very likely) then just order fittings to suit pipe diameter, ie. 1/4 to 10mm.

If valve is tripping then just replace but go for a 95c to prevent nuisance tripping.

Also is there an underlying reason why the valve is tripping rather than failing?

 

[Avocet]

Thanks all. The copper pipes in and out are, indeed 10mm diamter (external).Each has an olive on the end and pushes into the KBB valve, which has two 10mm female bores in externally threaded bosses.

I can't blow through it, regardless what I do with the plastic knob on the back. It only seems to move a few mm, bit it doesn't make any difference.

I've never had it trip before, but for a few months now, the boiler fan / pump assembly has been making a faint squeaking noise - just like a dry bearing. It's a Worscester Heat Slave boiler. Also, I've thought the flame (when running) didn't sound quite right, a bit uneven. Removing the KBB valve has fixed that instantly, so I'm wondering if the flow through the valve has been poor for a while?