Smokin' boiler

[cwr]

Hey folks, 

This weeks fun is trying to sort out the oil boiler. It's a recent but second hand unit. Ran fine for a couple of months then developed thick white smote. Def smoke, not condensate. Was pretty sooted up inside so cleaned it out and replaced the nozzle. Seemed fine for a couple of days but then back to the awful smoke again. 

I did notice that the baffle plates have only a couple of mil clearance to the inside wall, not sure what that should be? The problems did start during a cold spell so even wondering if theres been some freezing and the heat exchangers been pushed in a little closing the gaps, though there's no obvious frost damage to it or the copper pipes feeding it. (the boiler's installed outside in a galv housing).

Giving it more air has no impact, and the oil being delivered to it looks clean. 

Any thoughts?

Thanks 

[markc]

What flow temp are you running it at? Have you turned the temp/s down?

[cwr]

Not particularly high. The stat on the boiler is graduated 1 to 5, but I guess something like 50 to 60 Deg. I'll get round to measuring it when it will run cleanly.

[markc]

2 minutes ago, cwr said:

Not particularly high. The stat on the boiler is graduated 1 to 5, but I guess something like 50 to 60 Deg. I'll get round to measuring it when it will run cleanly.

Hi, try turning it up a bit, or even to max for a short while. Good chance it will clear and run smoothly, then you can take it down a bit at a time. A boiler trying to run too low will not burn cleanly

[dpmiller]

it it actually igniting? Vaporised fuel is a stinky white.  What make and model/ can you fire it with the plates out, to visualise the flame shape and size?

[cwr]

My gut feel is that the water temps a minor variable in this case, but i could be wrong so might be worth checking.

 

Yes it Ignites straight away.

 

It's a Warmflow BH series.

 

I fired it up in the ground out of the boiler, not too sure if the flame shape is correct or not. The flames seem to lick round the inside of the burner a bit. I expect it would look different inside the boiler.

 

Tomorrow eve hopefully experiment with the plates out. 

[Nickfromwales]

This needs proper commissioning. Get an OFTEC reg'd installer out and stop messing about with it yourself?  

[dpmiller]

Nick's on the money on this one unfortunately, unless you've got at least a pressure gauge, but really a combustion analyser. My gut says that flame is a bit small but I don't see the sparkly stars you'd expect with *really* low pressure. Is it set up at a standard trim per the manual (jet spec and air number?)

 

 and make sure all the HE plates are flat, a really bent one will feck with the chamber pressure.

 

 

[ProDave]

Yes you need someone with a flue gas analyser to set up the burner. Money well spent.

[PeterW]

@cwr too many variables here - chamber pressure, oil pressure, airflow, nozzle size, oil viscosity.. all can make a difference to the burn and unless you have the kit to check them all then getting someone to look at it is usually the easiest option and cheaper in the long run. Given white is usually unburnt fuel, you will be wasting a lot just finding the problems. 

[cwr]

Thanks for the replies and advice.

There will be someone coming round to comission it at some point soon, was just trying to get it running reasonably in the meantime time.

The plates look to be good condition.

Still, in my mind something has changed. It ran 'fine' for a couple of months and now is very different.

I used to have access to a flue gas analyser when I worked wit gas appliances, but unfortunately not any more and don't see any point buying one.