Neal Lewis Posted May 21, 2006 Report Posted May 21, 2006 Here is a pic of a gas boiler that is only a couple of years old. This thing must have been producing soot from day one. The burner flames were solid orange and rolling out the front. The system was obviously not professionally installed. The adjacent boiler was clean as a whistle, but was half the BTU's. I know there might be a combination of reasons, but is this caused by insufficient gas pressure? BTW, there was heavy soot deposits in the first floor apartment.The boiler was running continuously and didn't respond to the thermostat. The apartment temp was regulated by opening the windows. The occupant had suffered from a stroke more recently. Download Attachment: boiler 004.jpg 62.47 KB
Bill Kibbel Posted May 21, 2006 Report Posted May 21, 2006 I would guess insufficient oxygen for proper combustion and improper venting of the exhaust. "The occupant had suffered from a stroke" Uh-oh. I've read many articles that state chronic CO poisoning is frequently misdiagnosed as, among other ailments, a stroke. Carbon monoxide displaces oxygen in the blood.
hausdok Posted May 21, 2006 Report Posted May 21, 2006 Betcha there's a blocked flue there! OT - OF!!! M.
StevenT Posted May 21, 2006 Report Posted May 21, 2006 I agree with flue problem and would also check air mix at burners.
Jim Morrison Posted May 21, 2006 Report Posted May 21, 2006 Neal, I think Bill's is right. You need at least 50 cubic feet of combustion air per 1000 btu's of the equipment's rating for safe combustion and draft -more if there is a laundry setup in this room as well. That soot was most assuredly not caused by low gas pressure. Jimmy
Neal Lewis Posted May 21, 2006 Author Report Posted May 21, 2006 Guys, The boilers are in a wide open basement; no problem with combustion air. The draft hood spill switch did not shut the boiler down. There was an opening into the base of the chimney which showed that the flue was clear at the bottom. The adjacent water heater and boiler did not have any drafting problems or soot buildup. I believe that the section passages are now blocked with soot, causing the extreme flame rollout, but something was causing the excessive soot production to begin with.
Jim Morrison Posted May 21, 2006 Report Posted May 21, 2006 Originally posted by Neal Lewis Guys, The boilers are in a wide open basement; no problem with combustion air. The draft hood spill switch did not shut the boiler down. There was an opening into the base of the chimney which showed that the flue was clear at the bottom. The adjacent water heater and boiler did not have any drafting problems or soot buildup. I believe that the section passages are now blocked with soot, causing the extreme flame rollout, but something was causing the excessive soot production to begin with. Neal, You may be right, but just because the basement was wide open, doesn't mean they had enough air. Consider this: A single boiler with a 100,000 btu input needs 625 square feet of basement (assuming an 8' ceiling which would be high in my area). Two boilers that size would need 1250 square feet. Add in a couple of water heaters and you can see that most basements aren't big enough to supply them all with enough combustion and dilution air. If you there is a clothes dryer (which draws air from the basement and vents it outside), and it's not hard to starve a boiler for air. Anyway, you noticed the problem and no doubt told your client to have it checked out by a heating expert. Job well done.
StevenT Posted May 21, 2006 Report Posted May 21, 2006 If it was starving for air, wouldn't that cause a small flame, do you think it would cause soot? If the air mix was out of adjustment, at the burners... couldn't that cause a poor flame and sooting? (lazy yellow) It the flue was blocked or was not getting proper draft, couldn't that cause a poor flame, sooting and roll back?
mgbinspect Posted May 21, 2006 Report Posted May 21, 2006 Just food for thought... If it's a particularly long and oversized masonry flue the gases could be cooling and becoming heavy before exiting. This can cause all the same problems as a blocked or restricted flue. A draft inducing fan may be necessary. Also, old brick masonry flues usually were separated by simply a brick shiner stacked up the chimney, which I've never understood. It's a really bad idea because eventually they tend to fall into the flue to one side or the other blocking the flue.
Jim Morrison Posted May 22, 2006 Report Posted May 22, 2006 Originally posted by StevenT If it was starving for air, wouldn't that cause a small flame, do you think it would cause soot? If the air mix was out of adjustment, at the burners... couldn't that cause a poor flame and sooting? (lazy yellow) It the flue was blocked or was not getting proper draft, couldn't that cause a poor flame, sooting and roll back? Yes, lack of combustion air will cause sooting. As will the other conditions you mentioned.
Les Posted May 22, 2006 Report Posted May 22, 2006 My first guess is blocked jacket. This would cause that amount of soot very quickly. Also the flame shield is not burned away and does not look warped, so the temp never was getting too high. All soot is air/gas mix and if the sections were obstructed at all, they would build soot. Jim brings up a good point re: combustion air. Most inspectors do not think this through and assume a large basement will have lots of free air. Pull the jacket and clean it up and set burners - betcha' it will be fine.
a46geo Posted May 26, 2006 Report Posted May 26, 2006 "Roll out" like that when adequate combustion air is available can only mean one thing, an obstruction. The obsruction could have started anywhere in the exhaust system but will eventually plug everything up all the way back to the burners. The amazing thing here is that you didn't mention anybody being killed by the fumes.
hausdok Posted May 26, 2006 Report Posted May 26, 2006 George wrote: The amazing thing here is that you didn't mention anybody being killed by the fumes.Yeah, but the occupants probably have very pink complexions and the neighbors have probably been shaking their heads for months and saying something like, "Poor ____ and _____. They've always been such nice folks. Have you noticed how red their faces are lately? They must be hitting the bottle pretty regularly these days. What a shame!" OT - OF!!! M.
MechAcc Posted June 11, 2006 Report Posted June 11, 2006 [:-crazy] This is why any gas or oil appliance should be setup using an electronic co/combustion meter and a draft gage. Another possible cause for the sooting is no bypass loop on the boiler. Newer boilers have less mass and less water. If the boiler is installed on a system with cast iron radiators a lot of cold water will be returning to the boiler. A bypass loop allows a small portion of the heated water to mix with the return water and bring the temperature up and reduce condensing and sooting.
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