sooty chimny and back pressure burner

Old 11-26-06, 07:57 PM
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Unhappy sooty chimny and back pressure burner

Last heating season I installed a new beckett burner in my oil fired boiler. This year I had to clean the chimny and found lots of black soot. I knew my mixture on burner was too rich so this fall I opened the air nearly twice as large. Upon firing up the burner pressure was so strong it backed out of the view port and when the burner fires I get a sulfur smell in the house. It seems to me the Burner nozzle is too large. Is this my problem?
Old 11-26-06, 08:06 PM
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Id say best to call a tech in and check that burner for you. Be there when he comes and go over the burner with him. You can have lots of thing that are not right .On that burner you dont

I opened the air nearly twice as large

Also not just soot in the flue you sure its clear and not blocked. Is the boiler clean?
What was the nozzle size in the old burner???? what is it in the new burner.
You have so many things to look at . That is why I say call a tech

Old 11-26-06, 09:58 PM
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Sooty Heating Unit

Ed is right

Anytime a boiler/chimney soots up everything has to be cleaned of soot; that includes the chimney, the flue pipes between the chimney & the boiler, the heat exchanger & the combustion chamber; most boilers have a special brush to clean the push nipples & HE passages.

Soot is nasty to breathe, wear a dust mask designed to stop paint odors/droplets to protect your lungs.

Once soot starts to form, often due to too rich a flame, it begins a vicious cycle, smoke/soot starts to clog up the heat exchanger, flues, chimney, causing restrictions, reducing needed hot air draft currents up the chimney, causing more soot & restriction, etc.

This often cooks the nozzle, which spurts out a richer mix of oil (check the nozzle head for any distortions & replace).

The chimney can be inspected by holding a mirror at the chimney's inside base cleanout during daylight hours to see if you can clearly see light at the the top of either the steel or masonry structure; check for large soot deposits & any bird nests or other restrictions.

Chimney-cleaning brushes made of steel wire that conform to your chimney shape with the screw-in rod connectors are avaialble at plumbing supply stores; the base of the chimney has to be temporarily blocked with rags or similar material while you clean the chimney of soot, so soot doesn't enter into the boiler room or living quarters.

Soot is often caused by a flame out
of adjustment, which requires the use of a combustion analyzer, smoke tester & flue temp gauge to get the right flame combination of low smoke, low CO, & the right levels of CO2, & O2; these adjustments can't be done by eyeball; thus, a tech should be called in to adjust the flame.

Sounds like you're having draft problems(inadequate air going into the combustion chamber) ; make sure adequate air is coming into the boiler room, especially if there has been a lot of insulation & crack sealing done recently; boilers need a lot of air to induce draft, create a bright yellow flame with no smoke, & get the products of combustion up the chimney & out of the house.

Hold a smoldering rope near the open boiler observation port when the burner is running, you should see the smoke rapidly enter the combustion chamber if you have adequade draft.

The pump pressure has to measured with a pressure gauge (usually ~100 psi,) & checked with the specs in the owner's manual, and/or burner manual; also check the manual or mfg to make sure you got a match between the boiler & the new burner assembly; check the oil tank for dirty oil or water contamination; change the filters & strainers; there is a water-detection paste you can put on the end of a pole to check the presence of water in the tank.

Last edited by jack horner; 11-26-06 at 10:20 PM.

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