Strange white powder on back boiler

[alexh75]

Hi
We have a Baxi Bermuda 401 back boiler, has been running fine for years, but pilot light went out at the end of last week and I couldn't relight it. So called in the Corgi engineer today.
He took off the fire at the front, and diagnosed the problem immediately, the pilot was clogged. Not with soot, but with a fine white powder (probably halfway in texture between talc and washing powder). In addition, this white powder was distributed fairly evenly all over the combustion chamber, and the heat exchanger, and even at the bottom of the flue. Does anyone have any ideas what this could be and why it is being produced?
Thanks
Alex

 

[ChrisOxford]

Alex,

How old is the boiler, and when was it last serviced?

Did the engineer have any ideas as to what the dust was?

The only white thing I can think of within the boiler would be the insulation panels, which shouldn't be crumbling anyway, so presumably, it came down the chimney. I will be intrigued to see what the experts say.

 

[gaswizzard]

Has the room been decorated @ some point?

Pilot blockage would obviously be nothing to do with above.

 

[namsag]

Very common its a product of combustion when boiler is not burning properly cant remember the proper name for it think it ends in ide

 

[alexh75]

Boiler is approximately 25 years old I believe.
Last serviced in February 2011.
Engineer hadn't seen anything like this before (and he's been in business for around 30 years). Only thing he could think of was that if the flue/boiler surround was galvanised there may be a chemical reaction producing some sort of of Zinc Oxide?
Room was last decorated around 4 years ago.
Alex

 

[gaswizzard]

How long is the flue route from boiler to terminal?

 

[alexh75]

How long is the flue route from boiler to terminal?

terminal....you mean the top of the chimney? around 15-18ft
excuse my ignorance....

 

[misterdubya]

Very common its a product of combustion when boiler is not burning properly cant remember the proper name for it think it ends in ide

When you say 'not burning properly', what exactly do you mean? I have a bbu I service every year and always is .0002 on the Analyser - well has been for the last 10 years. Caked in the stuff every year.

Just curious. Ally Oxide in old Glowworm Fulesavers / Myson Apollo's I can understand. Cast Iron BBU's - I guess I'm no scientist.

 

[alexh75]

Very common its a product of combustion when boiler is not burning properly cant remember the proper name for it think it ends in ide

When you say 'not burning properly', what exactly do you mean? I have a bbu I service every year and always is .0002 on the Analyser - well has been for the last 10 years. Caked in the stuff every year.

Just curious. Ally Oxide in old Glowworm Fulesavers / Myson Apollo's I can understand. Cast Iron BBU's - I guess I'm no scientist.

That's exactly what my engineer said, no combustion problems he could see and had it been an alu heat exchanger he would have understood, but not on a cast iron HE.....

 

[Onetap]

He took off the fire at the front, and diagnosed the problem immediately, the pilot was clogged. Not with soot, but with a fine white powder (probably halfway in texture between talc and washing powder). In addition, this white powder was distributed fairly evenly all over the combustion chamber, and the heat exchanger, and even at the bottom of the flue. Does anyone have any ideas what this could be and why it is being produced?

Is it a coke fired boiler?

 

[alexh75]

no, gas

 

[ChrisOxford]

I think OneTap was making a joke, Alex.

Think Angus Deayton

 

[Jordon]

When it was serviced did they do a smoke test? Had this after some rgi used a cheapo pellet.

 

[alexh75]

I think OneTap was making a joke, Alex.

Think Angus Deayton

LOL!
Sorry, brain not switched on there....
Funny....

 

[alexh75]

When it was serviced did they do a smoke test? Had this after some rgi used a cheapo pellet.

yes he does this as a matter of course, using analyser