Noise in Exhaust Chimney
#1

We just moved into a new home and have just recently started to use the furnace as it is now cold outside. In this home, the furnace is in the middle of the basement and, as a result, the exhaust chimney goes up through the middle of the house. Whenever the furnace turns on, there is an annoying tapping noise in the wall where the exhaust chimney runs through. I understand that metal expands and contracts due to the change in temperatures, but is there anything that can be done to eliminate the tapping noise without having to tear out walls?
#5
mnbadam4:
If you are unable to secure the chimney where it is accesible, you will as fjrachel said, somehow have to get to the chimney where it travels to the roof to find out where it is making noise.
If you put something like a piece of broom handle between the wall and your ear you may be able to pin-point the source of the noise.
If you are unable to secure the chimney where it is accesible, you will as fjrachel said, somehow have to get to the chimney where it travels to the roof to find out where it is making noise.
If you put something like a piece of broom handle between the wall and your ear you may be able to pin-point the source of the noise.
#6

When hearing the sound to see if its fron the chimney or the furnace, try shutting down the furnace with the service switch after it starts making the noise, in an attempt to isolate the location of the sourse.
You may also want to have an efficiency test to make sure you don't have the furnace overfired, this would send excessive heat up the flue. Modern furnaces should have a much lower flue temp. The 90 plus condensing gas furnaces on the market for the last several years even use plastic pipe for the exhaust.
You may also want to have an efficiency test to make sure you don't have the furnace overfired, this would send excessive heat up the flue. Modern furnaces should have a much lower flue temp. The 90 plus condensing gas furnaces on the market for the last several years even use plastic pipe for the exhaust.
#7
Noises
Another thing to try is to open the cleanout door to try hear the sound from there. Get the wifes make-up mirror and a good flashlight and try look up the chimney to daylight. Some of the old masons would mortar a pane of glass in the liner to block the air flow to the chimney until they got paid. Upon getting paid, they dropped a brick down the liner to shatter the glass blockage.
Oh!, do you have a fire place? with a damper control? If so the metal parts MAY be expanding in a tight place making the noise.
Oh!, do you have a fire place? with a damper control? If so the metal parts MAY be expanding in a tight place making the noise.

#10
Why not one more country heard from. Is this a single story or two story, can you get to the attic where the B-vent come through to the roof? If so.get to the attic and look down the chase...........it should be large enough to look down with a flashlight. Code requires so much clearance between b-vent and wood.....possibly some was dropped in the chase.(during construction) or forgotten to be secured.