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AGWhitehouse 08-12-2011 08:41 PM

Chimney smoke?
Took this picture while outside grilling when the furnace kicked on for hot water to the dishwasher. The smoke started darker than shown and faded until relatively clear. Is this normal? Or is something needing adjustment (nozzle, etc.)?

Backstory: I had the Fire Department show up about 2 months ago on a call from a neighbor because black smoke was pouring out of the chimney. Turned out the boiler was 100% clogged with soot. So I swept the chimney, breeching, and entire boiler. Replaced the chamber kit, oil filter at tank, and spray nozzle on gun. Took me forever and made quite a mess, but it's my greatest DIY accomplishment to date. So now that I saw that smoke, could there be an adjustment issue with the nozzle? Or am I just being naive?

Current Rig: Weil-Mclein 66-68 boiler with 1.0 80deg hollow nozzle for a 1,000sq.ft. home in central Connecticut. Wall R-value is approx. R-15 and attic has R-40+

REP 08-13-2011 01:09 AM

That kind of smoke is usually unburnt fuel.It is carbon flakes.
Some thoughts on your situation.There might still be carbon deposits left on the boiler sections.
The oil pressure could be off.The pump screen could be plugged.The air adjustment could be off..
The proper way to do this is after you know the pump is clean and the pressure is right you adjust the air to zero smoke,and leave it there.
You loose a couple points of effiency but it stays at a high level of effiency for hopefully the whole year.
OH and as a side note,I think 112,000 BTUs is way way too much for 1000 sq ft.

AGWhitehouse 08-14-2011 04:36 PM

Thanks! I've adjusted the air to allow full combustion as a temporary means until I can get to a plumbing supply this week to get a reduced nozzle size. A friend told me I should be running 0.6gph. Does that seem reasonable?

yuri 08-14-2011 06:28 PM

depends on the gph rating of the boiler and burner whether it can have a stable flame/proper ignition and is determined by the manufacturers. smoke is cause by too much oil and not enough air or unburnt oil in the chamber at startup which is what you seem to have. you will never have a efficient flame and boiler eyeballin it and may want to get an experienced oil tech to find out what REALLY is goin on and to set it up efficiently.

REP 08-14-2011 07:52 PM

Oil equiupment,especially boilers are desiugned to work in a certain range of burner output.I myself would be very hesitant to deviate by more than 10%.
Too low a tempature and you xcould induse condensation in the boiler which would cause excess soot buildup on the boiler sections.
Baseboard radiation is desighned to give up heat at a supplied water temp.If you lower the nozzle size too much it won't be able to keep up with that needed temp supply.
There is such a thing as lowering the nozzle size and increasing the pressure to get a better burn but then you are changing the size of the output and you need somebody that really really knows his stuff .
What you reeally need is a service where all the various things like tempature , draft, pressure,smoke,etc etc.are set up with instraments , ONLY WITH INSTRAMENTS.
I'm sorry but the only things you can do is make sure your filters are changed every year.
( side note , for the oil tank a micro filter is far and away a better filter to clean the oil before suppling it to the burner )

AGWhitehouse 08-14-2011 11:29 PM

Thanks a bunch! I've got the test equipment available and people who know it well, so I'll have to give them a call....

beenthere 08-15-2011 04:23 AM

0 smoke is often not the correct setting for an oil burner, specially on water boilers. Causes the flame to be too cool. And can cause the sulfur in the oil to condense in the chimney. On large water content boilers, it can also cause condensation in the boiler flue passages, and its not fun cleaning that gunk out.

Needs to be set up with an analyzer, to make sure its burning clean enough, and also doesn't have too much excess combustion air.

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