Damper in ductwork

[jsigns]

This is the ductwork from a oil fired furnace to the chimney. unit instaled in 03. Never have seen it before. Seems to be sucking air in to assist in the draft, but wanted to make sure it was not dangerous. 1st time posting. Hope the picture is attached.

[Jason1]

Originally Posted by jsigns

This is the ductwork from a oil fired furnace to the chimney. unit instaled in 03. Never have seen it before. Seems to be sucking air in to assist in the draft, but wanted to make sure it was not dangerous. 1st time posting. Hope the picture is attached.

That is normal in oil fired furnaces. It is a barometric damper

[David A. Andersen]

Before you start determining the installation of HVAC equipment, I would recommend you take some courses and only report on what you know is not right.

IAW SOP you are only required to run the HVAC from the T-Stat. No further evaluation is required or expected.

If you don't know what you are looking at, I would recommend that you do not get involved, as this is not a requirement of HI's.

You will find this damper in oil fired boilers/furnaces. It has a purpose. Just because you have not see it before, does not mean there is a problem with it.

[jsigns]

I've seen other oil fired furnacces without this. Is there a reson it would be in some but not all? Thanks, John

[Michael Larson]

Barometric Draft: The swing damper on the vent connector controls the draft up the chimney. If the draft is too high, the hot flue gases will pass through the heat exchanger too quickly, sending the heat up the chimney. Draft should be a set a 0.02"W.C.- 0.03" W.C. with a draft gauge. This very small amount of pressure is the equal to a velocity 566FPM - 694 FPM (Feet Per Minute) If the barometric damper door is sticking or does not open at all, it will not control the draft properly. Draft can reach 0.08 W.C. or 1133 FPM. As the velocity of the flue gas increases less heat is absorbed into the supply air to heat the house and more heat goes up the chimney.

[Jason1]

A barometric damper isolates the burner in the furnace from changes in pressure at the chimney exit.Whenever the chimney suction is greater than the furnace’s needs, the flap rotates open and lets room air into the chimney.

Proper adjustment of the barometric damper is important. While it is a signifi cant part of the heating system, it is also a huge leak in the system. The damper can allow combustion gases to leak into the house, especially when
large exhaust devices, such as a dryer or a range hood, are operating. Also, if the damper is improperly adjusted, it can waste much of the heat produced by the furnace.

[jsigns]

Thanks for all of your help. I was asking to better educate myself and I was concerned about the safety issue of carbon monoxide.

[Jason1]

Originally Posted by mlarson

Draft should be a set a 0.02"W.C.- 0.03" W.C. with a draft gauge.

What kind of tools do you carry around?

[Jason1]

Originally Posted by jsigns

Thanks for all of your help. I was asking to better educate myself .

Good job, I would recommend you take an HVAC inspection course.

[Michael Larson]

Originally Posted by Jason1

What kind of tools do you carry around?

Little beyond the scope of a home inspection eh?

I use to have easy access to a draft gauge.