Hey all, is it unusual for the pipe running to the chimney from a forced hot air furnace (oil) to be fairly hot? Seems like we’re throwing an awful lot of heat right up the old chimney. Possible I need to add more air return ducts perhaps?
Brian
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That is one of two reasons for having a chimney.
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ok, I'll bite..what's the other one? Santa Claus? LOL
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vent out the CO and water byproducts of combustion.
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You're in trouble if it isn't - that is the vent, carying the combustion gases from the heat exchager to the chimney flue.
As a general rule, a natural draft ("atmospheric") furnace using natural gas will have flue temps before the draft hood of about 415 - 515 degrees, a natural gas induced draft 80+ about 300 - 400, a NG condensing 90+ about 120-140 degrees.
I don't have the figures for oil burners handy, but they will be higher than those, if I recall.
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That's the difference between older heaters and new efficient ones. The new ones have so little waste heat, they can vented trough PVC pipe.
We had a problem around here a few weeks ago. We had about 2 feet of snow for the first time in years. Many people discovered that their new heater vents coming though the wall (no chimney needed) were too close to the ground and were getting blocked by snow and CO was getting into the house.
Al Mollitor, Sharon MA
>>Many people discovered that their new heater vents coming though the wall (no chimney needed) were too close to the ground and were getting blocked by snow and CO was getting into the house.Every installation instruction I've seen for the condensijng type call for the flue to be 18" above grade AND the 'typical' snow level.Few are.
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How was co getting into the house? These are usually sealed combustion units. And if the vent is plugged there is usually two different safety switches to shut the unit down.
I don't know those details, Rich. There were a couple of stories on the news about this, but - luckily - I had no personal experience with this problem. I have seen several of these vents that exit pretty low, however. I would have thought they would melt their own channels through the snow. You can be sure I'll be paying more attention in the future.
Al
>How was co getting into the house? These are usually sealed combustion units. And if the vent is plugged there is usually two different safety switches to shut the unit down.
One possibility is blowing the exhaust gases through the condensate lines.I've never seen it, and don't know that it could happen, but I don't see why not, either.It's my understanding that the 90+'s prove the air intake, but not the exhaust (or do I have that backwards? Senior moments reign with a glass or two of the grape....)
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