Cannon Oxford cooker

[nick]

The oven and all four hotplates light instantly.

But the grill on this gas cooker doesn't ignite properly.

The spark at the electrode looks fine; 5mm plus. New battery fitted.

There doesn't seem to be any blockage in the grill burner which looks very clean.

Gas is getting to the burner. The electrode is down the far end of the burner from the gas inlet.

If I turn the gas on full, then hold in the spark button and blow under the grill the gas usually ignites.

But it refuses to ignite from the spark if I don't blow on it.

When it's burning the flames seem to come out of all the jets of the burner.

The flames extend about 4-6" out of the jets.

This has me stumped. Any ideas?

[GB]

This could just be a design flaw. Apart from that, take the burner out and give it a good clean. Are the flames blue, btw?

[Dave Liquorice]

A long spark is a weak spark, the energy is going into breaking down lots of air to make the arc rather than ionising more air on a shorter arc.

I'd check that whatever it is arcing to hasn't moved or erroded away, same applies to the electrode. If all looks positioned OK I'd be tempted to *gently* bend the electrode to make a spark say 3mm long.

[nick]

There must be millions of these things out there; all with non-igniting grills?

Took the burner out. Could be stainless steel. It is so clean it looks like new. Doesn't look like the grill has ever been used. Now I know why.

The flames are blue except at the tips where they are yellowish.

[nick]

Point taken about the spark. But a longer spark has more chance of passing through the gas?

But I'll try a shorter spark.

The electrode arcs to the lower edge of the burner. Right next to the last jet on the burner.

[Andrew Gabriel]

which suggests the air inlet at the jet is obstructed, but could also be caused by dust further along the burner generating resistance to the gas/aid flow, the back-pressure from which will reduce the air drawn in alongside the jet. It's probably generating a little more carbon monoxide than it would if operating cleanly.

You may need to clean the inside of the burner tube. Often a blast with a compressed air can will do, but if there's a spider's nest in there, you'll need something more substantial.

[GB]

shouldn't be any yellow

And check the jet where the gas is squirted into the burner.

By the way, to clean it, you can just run it under the tap.

[Dave Liquorice]

But the further the gas is away from the burner jet the more dilute it will be and possibly outside the required range for ignition...