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After noticing some smell associated with a new oil furnace (but no carbon monoxide), I called the installer for a check up. He said the chimney was not drawing, and to have a chimney sweep take a look. The sweep demonstrated the lack of draft with a lighter and showed me condensation inside the flue. His diagnosis is that the more efficient (but rated as moderately efficient) new system does not put out enough heat to induce a draft. His solution is a $2000 stainless steel flue liner. Two questions: 1)this is all occuring during a cold spell at ASHRAE 97.5% temperature conditions…do I really need a liner if the system is in a sealed room with no carbon monoxide problem and generally warmer conditions, and 2) will simply lining the long straight run of the flue be enough to induce draft? His cost is clearly jacked by the perceived requirement to poke holes in my chimney and get a continuous lining inside an intact, healthy flue that has worked since the mid 1950s. Thanks in advance for all opinions.
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Don,
You have a potentially dangerous and even _deadly_ situation here and need to take action as soon as possible. At a bare minimum get and use CO alarms - get the ones with an LED readout. Use one in the Bedroom areas, one in the main floor living areas (if on another level) and one in the furnace area, but not within 5 feet of the furnace or water heater. Have the drafting problem resolved as soon as possible.
Even assuming CO production was properly analyzed that only answers CO _at the time of the test. (What was measured, CO in the room or CO in the flue gases? Over what period of time was it measured? Was a draft guage used during the testing and were other vents in the house operated during the tests? See the Buidling Performance Institutes CO analysis protocol at http://home.att.net/~cobusters1/)
Since the furnace (you do mean furnace and not boiler?) is in a sealed room, a combustion appliance can go from low or no co to very high levels very quickly. The principle by-product of combustion is carbon dioxide. CO2 is heavier than air, so if not vented, it will build from floor level (after the relatively rapid cooling as it's mixed with house air.) When the CO2 builds to burner level, the flame will be robbed of oxegen and CO production will become significant.
__CO can kill, it can also cause very serious health problems at lower concentrations. Note: infants are particularly sensitive to CO, as are the elderly and those with heart and respiratory problems.__
There is a good chance that leaks in your return air system are pulling air from the furnace room (according to studies which I have read) so that if this jump in CO occurs, you could spread CO throughout the house.
FredL stated <>
That's not the way I've learned it, but I do not claim to be an expert in the area of venting configuration. Try to get some other opinions here. Every installation varies.
FredL's other points are, IMO, well taken.
Please take action now and keep us posted as to your final solution.
Bob Walker
Carbon Monoxide Analyst
Paradigm Inspections
NW Ohio
*Thanks Bob and Fred for good food for thought. I have two CO monitors going...upstairs bedroom area and first floor, and can't get an above zero reading even in close proximity to the oil furnace. Am hesitant to go for an infiltration reduction solution under the circumstances, but that is part of my long term plan. The contractor who installed, who I trust and have worked with on previous houses, took my flue size, horizontal run, chimney height, and duct size to the chimney and used a chart to determine that I theoretically should have no problem. However, I can see the cloud pluming out of the top of the chimney and it is a contrast to the neighbor's fast moving hot air. We're snowed in now, but I had a more technical sweep coming today who does CO testing and will clean the horizontal run, which is around 6 feet. After that event, hopefully at more seasonal temperatures, we will see about a liner. His approach is to tear out the original 7x12 liner, run continuous steel, and insulate. Sound like the serious extreme to me...I still think lining the vertical run will induce the needed draft...
*Update...the second sweep found blockage in the horizontal (20 degree slope) run and lost a bit trying to open the area up. As a result of his efforts, the measured draft is reportedly appropriate, but he says we will have problems in the future (and there is still considerable debris in the horizontal run). He recommends rerouting the flue outside the chimney so that there are fewer bends and no horizontal runs. I am more inclined to try and punch a small cleaning hole in the chimney to allow a more thorough cleaning. I am faced with a recommended solution that has become more costly, unsightly, and hard to buy off on...any ideas would be appreciated.
*At the risk of talking to myself, here is an update for anyone following this...current draft measures .03 - .04 according to sweep referenced above. Flue is bendy with a long horizontal run and is "horrible for oil furnace." His ideal option is a "powervent" that fan-forces draft to a new, short outside chimney. Cost unknown. More reasonably, he thinks a single cleanout can be drilled to allow him to get to the horizontal run (where the debris is) and keep the draft acceptable until the liner deteriorates to a point where further action is required. I will probably look into a small air-to-air heat exchanger so that the furnace room has its own air supply and then see what happens. Don
*Don,Assuming the reported draft of .03 - .04 is Water Column inches, that's a pretty good draft, even a bit high.Under the Building Performance Institute's Carbon Monoxide Analysis Protocol (available online at http://home.att.net/~cobusters1/coprotocol.htm), a normal boiler draft is .01 to .02 WC.Too high a draft can, in some cases, cause problems by creating an "air curtain" in the draft hood which can block the combustion gases from rising into the flue. If this happens, the flue gases back up in combustion chamber(s) and the burner will start to produce major CO as the oxygen is blocked by the backed up combustion gases.I've never seen this, myself, but have been told by experts that it can and does happen.Be sure that when drafting is tested (i) it's tested over a 5 - 10 minute period and (ii) various doors (especially a garage door in an attached garage) are opened and all other venting appliances (bath & kitchen fans, etc) are operated to determine whether they affect the drafting.Bob
*That's a good measurement for the stack draft. Should be .01-.02 over fire and .03-.04 AC at the stack, measure within 24" of outlet of furnace. As for sidewall enters, I LOVE THEM!!! Use them in all the houses I build. They guarantee draft before the furnace starts and post purge all the CO after shut down. Dampers help retain boiler hemps. I buy them complete for about $320
*Don, nobody pointed it out, so I thought I would. Just because your CO detectors read 0, it DOES NOT mean that there are 0 levels of CO in the vicinity. CO detectors are designed to show a 0 reading for anything below 35. Something to do with UL labs or something. That is if they are the standard type homeowner models. If they are more sophisticated professional gear, they will show readings below 35. But your run of the mill CO detector will not display any reading till it hits 36.
*Fred,I see you are still deleting your messages shortly after posting. That is indeed a shame, and frustrating to me as someone interested in your insights. I wish you would reconsider the practise.Wondering what you said,Steve
*Axle:what are "sidewall enters"? Barametric dampers?FWIW, the leading expert on CO analysis, Jim Davis, is a big fan of barametric dampers.
*Steve...Fred deleted almost a year ago...near the stream,aj
*Who makes the most cost efficent [procurement and operation] tankless water heater? Is there a rule of thumb about how close these should be to a limited use supply point?
*
After noticing some smell associated with a new oil furnace (but no carbon monoxide), I called the installer for a check up. He said the chimney was not drawing, and to have a chimney sweep take a look. The sweep demonstrated the lack of draft with a lighter and showed me condensation inside the flue. His diagnosis is that the more efficient (but rated as moderately efficient) new system does not put out enough heat to induce a draft. His solution is a $2000 stainless steel flue liner. Two questions: 1)this is all occuring during a cold spell at ASHRAE 97.5% temperature conditions...do I really need a liner if the system is in a sealed room with no carbon monoxide problem and generally warmer conditions, and 2) will simply lining the long straight run of the flue be enough to induce draft? His cost is clearly jacked by the perceived requirement to poke holes in my chimney and get a continuous lining inside an intact, healthy flue that has worked since the mid 1950s. Thanks in advance for all opinions.