air/boiler

Having put fittings on the boiler of my locomotive, I piped compressed air into the low part of the backhead, but there is no movement from he wheels. I have tried undoing fittings (clack valves) from the boiler sides an blanking them, but still no movement. Just wondered if applying air so low down makes a difference, but there is pressure at the smokebox end, worryingly I piped directly from boiler exit to cylinder entry, still no movement,piping from compressor to cylinders and all is OK. Any suggestion (or advice gratefullly received

Has the boiler had a hydrostatic test with water only, to twice working pressure? If not do not apply air pressure at all.

Be VERY careful pressurising a boiler with air, would suggest no more than 20 psi for a boiler with working pressure of 90-100 psi.

Is the regulator open? Does the motion rotate smoothly by hand? Are the valves adjusted correctly?

Hello Jeff, I did not build the boiler, but when I bought it, the relative of the builder told me it had passed various tests when constructed and it certainly looks well built. As for your other points. Regulator was open, motuion os quite free and ran very smoothly when ran on compressed air

Unless you have the paperwork to confirm that the boiler has been tested and certified, keep the pressures low.

If pressure vessel, under air pressure fails, it can be as dangerous, or even more so than a boiler under pressure.

Ask my friend who is minus his finger ends! (A compressed air tank exploded when he was beside it. )

You could try feeding compressed air into the Regulator, (disconnect from the feed from the boiler! ) and see what happens.

If nothing investigation for jammed / seized cylinder or motion or blocked pipes would be in order.

This assumes that the valve settings are correct.

If all else fails, you need to start checking that all passages are open, starting with the ports into the cylinder (means removing the cylinder ends ) and working back, through the valves and pipework, regulator, until you reach the boiler take off.

It is not unknown for the passage from port to cylinder not to be drilled through!

Even Fred Dibnah had to open up the passages on his engine whilst on his final round Britain trip!

Howard