Correct installation of a barometric damper for oil furnace

[acricketer]

Hi there. We had a chimney liner installed recently and have a question about the positioning of the barometric damper in the flue pipe connecting the furnace to the chimney.
Here is a picture:

Is the barometric damper correctly positioned?
Any feedback welcomed . Many thanks

 

[argile_tile]

The answer is always NO.

No matter what mechanic installs it however certified he or she is, the code says to test it after installing it.

Test it and you will know.

 

[argile_tile]

the mechanical code for hot gas is much like that for plubing water in many respects: except it runs up instead of down

we cannot see if you have a fan-forced hot-gas exit on the furnace

in the case of forced air, testing is different that for gravity, since the vent has different specs/data in that case

 

[argile_tile]

by allowing cool air into the pipe, not all of the pipe is hot gas. let's say 1/2 the flow of hot gas is now cold air. you now have only 1/2 the draft caused by the pipe length. the cold air is pulled in by venturi principle and does not effect the furnace burner.

that being said: a forced air system is "closer to perfect", but also uses a damper

 

[argile_tile]

now, from water plumbing, there is a standard "rise/run" for hot gas (assuming the pipe is not under-sized) which do not effect draft. and then there are "straight ups" which do: and the height matters.

So you need to know the gas exit rate preffered by your burning unit.

You then need as a flow meter (which can be used with hot gas) to measure the flow on various days. To see if the damper is operating your furnace safely and efficiently. Before that we'd assume you looked at the flame to insure the flame was good

 

[argile_tile]

I can tell you for sure only this: a "real mechanic" installed a damper on my natural gas furnace with forced air - and it was installed as we see in your picture.

However: the size of pipe and slopes were different and these are the factors the mechanic had to worry about and had to buy an extra pipe to fix - as he didn't have it with him and complained of his bad luck.

 

[argile_tile]

I just checked a forced hot-gas natural gas furnace in the house i'm in now: no flue at all. All electronic controlled (i hope).