Sticky muck in boiler

[MarkOil]

Hi, went to a customer today and inside the boiler was this yellow/red sticky muck which my hoover, scraper and pretty much anything that touched it didn't like.
Can anyone shed any light as to why or what it is? I was thinking it's maybe the boiler being too cold?
The previous nozzle was the wrong size, so don't really know what the previous combustion settings were.
I left it set up as it should be with the CO2 a shade under the mi's.
Any ideas?

 

[Bunker]

Yeah that's just as you say, it's been off for a few days or more. This is why I always tell my custards that I can't service a faulty boiler if its been off for a while. Repair, get it running then service.

 

[village idiot]

If CO2 is under MI spec, then better you service/repair then check CO2 again.

 

[MarkOil]

Thank you
Yes it had been off all summer, they use the immersion in the summer, I always tell the "custards" to use the boiler, because it would be similar to not using your car for 4 months.
When I say the CO2 is a little low, mi's want 12% I was told to set as mi's in summer, set 0.2% lower in the colder months, is that correct?

 

[Bunker]

If CO2 is under MI spec, then better you service/repair then check CO2 again.

Rollox. Most mi say 12% or 11.5-12%. Frankly I put it anywhere between 11-11.5 as long as CO is <50 and Xair is close to 30. Newer boilers are easier to fine tune.

 

[kimbo]

Have you never seen sulphur deposits in a boiler before

 

[Bunker]

Actually Im glad he raised this. Not sure if this is a Eureka moment or not but I serviced a boiler earlier in the week that hadnt been serviced for 10 years (!). The custard had forgotten to turn it off, when I arrived it was actually running but I thought Id crack on anyway, so big gloves on:
The plates and sides were thick with sulphur, I immediately thought it would be a nightmare to strip out but ALL of it just fell off, brushed the boiler back to metal inside without effort.
Was this coincidence or do you think scraping it off at high temp will work every time?

 

[MarkOil]

That could well be a Eureka moment! I'm going to bare that in mind now, Sometimes it's a right devil to get off, I've sharpened an old screwdriver to use like a chisel which is fairly effective.
What's this spray stuff like where it says there's no need to hoover? Just spray in and fire the boiler up? Personally I don't fancy it, I like to know I've left the inside as clean as I can get it.
Although it would be handy to get in the tight spots like in, is it potterton's with the fibre type shelves?

 

[kimbo]

Dual x works a treat

 

[Best]

If the boiler is damp inside, the red & yellow sulphur will scrape off easily, although will be a bit of a gunge.
If boiler hasn't been used for a while it will be damp often & also if rain water can enter the shell through the flue somewhere.
A spray of water on hardened sulphur & leave for a while & it will soften.

 

[Alemco]

Duel x is definitely the best for that really hard stuff. Products of combustion, especially the red stuff, when damp an wet become very gooey.
bare this in mind as well, bi carbonate of soda or soda crystals when immersed in really hot water and sprayed on the offending areas, especially on the secondary flues of the condensing boilers and stuck on baffles, will work magic for ya

 

[Roger Welton]

Don't rate the dual x stuff, personally prefer the kamco scale breaker ls3