Flame leakage from boiler

[snowman1]

When my CH boiler comes on, it behaves normally for about 17 secs. Then the flames turn orange and - most alarmingly - spread out much further than they are meant to go, the flames spilling outside the boiler casing. The boiler is a Vaillant VCW T3W, on which the pilot is not glassed in. I've turned it off, as this looks dangerous to me.

Can anyone give me an idea of the problem might be, and probable cost? Is this some kind of gas pressure problem, or an air leak? As far as I know the flue is ok (a large pipe that goes up through the house and vents through the roof).

I also noticed the water pressure is also too low - 0.6 bar - but I'm guessing this is unrelated. No obvious loop/tap to re-pressurise.

Thanks

 

[corgiman]

Cannot give you an idea of cost

but have to say GET A CORGI ENGINEER BEFORE YOU USE IT AGAIN

cor blimey thats very dangerous IMHO

 

[snowman1]

corgiman,
Absolutely! It's off and will stay off until we can get an expert round.

 

[corgiman]

Stout Fellow yourself

good luck

 

[Agile]

If the main heat exchanger is sooted up we would charge about £180 to fully sort it out.

In this case since it apparently operates fairly normally for 17 secs then thats unlikely.

Its almost as if an outside ventilation vent is blocked and the room is depressurised first before the symptoms of an inadequate air supply become obvious.

Highly dangerous!

Tony

 

[namsag]

Na its cause it light on low gas before stepping up which then shows up how badly sooted up it is. Horrible boiler to desoot . Get lots of dust sheets out

 

[snowman1]

Thanks all for your replies. Got someone coming round on Wed (these things pick their moment!). He did say it could be a blocked heat exchanger. We've only been in the house a few months and haven't put monoxide alarms in yet, just shows it's not a thing to neglect.

 

[namsag]

Rolls Royce of combi`s solid boiler only thing is they are coming up for 25 year old now

 

[bengasman]

with open flue appiances, a CO alarm is a must, get one asap, preferably even before the boiler is mended.

 

[snowman1]

Sorted - the heat exchanger was well and truly sooted up. It can't have been serviced in years. The chap told us that the boiler does indeed probably only have a year or two left in it, so that's large bill to look forward to!
Cheers all