oil furnace flue temp?

Question

my furnace flue pipe seems to get real hot.its a old oil furnace..is this normal or is the draft wrong,,,,what needs to be adjusted...the furnace doesnt kick on untill i set the temp about 6deg above what the house temp is,,what's going on there..and its giving off a dusty smell in the house

Answer 1

The flue pipe on an oil furnace will get real hot a low stack temp for an oil fired appliance is about 400degress,your old oil furnace likely has ahigher stack temp.If your t-stat has a mercury switch it may not be level,and that would cause the discrepancy.

Answer 2

Sounds like it needs cleaning, may be sooted up and or you have an airflow problem (dirty filter, squirrel cage, etc).
I probably should explain in more detail you see an oil furnace can build up soot deposits on the heat exchanger and since soot is a very good insulator the heat does not transfer to the air as much and ends up going out the flue pipe resulting in a higher than normal flue pipe temperature. Also If the filter is dirty your air flow is decreased resulting in less heat being removed from the heat exchanger, this increases the temperature of the heat exchanger resulting in a higher pipe temperature as you have stated. As for the thermostat it probably just needs calibration.

Answer 3

The first respondent is right, but I think for your own peace of mind you should call your company to check the furnace, specially if the pipe gets real hot..☺

Answer 4

Stack temperature should be no greater than about 450 deg. F. Higher readings often occur when there is too much excess air injected into the combustion chamber.

Answer 5

Birds nest?
Spider webs?
Hornets nest?

Climb the roof and look.