Furnace Flue

[relliott]

Originally Posted by badair

I have to agree with M.L. and noted as such this was not 3' above any roof surface but if it had been I wouldn't have noted anything. No evidence of problems and nothing to back it up, flue was pretty close to the 5:12 ridge.

btw: no backdrafting, spillage, roll-out or other issues were noted with the heat equipment associated with this flue and the entire BSL (Beyond Service Life) roof cover will be replaced and turbines will be replaced with continuous ridge venting.

Another question.

Will this retro-fit ridge venting system present new or the same issues for those that were in favor of mis-installation?

Barry I have been looking into this subject tonight and am convinced that the Turbine is a big problem.

It is made to spit out the warm moist air from the attic , and is interfering with the natural draft of the flue gases , which depend on the warm gases to rise.
This has the potential for backdrafting, whether or not you detected a problem at time of inspection.

[Joe Hugenroth]

Originally Posted by relliott

Barry I have been looking into this subject tonight and am convinced that the Turbine is a big problem.

It is made to spit out the warm moist air from the attic , and is interfering with the natural draft of the flue gases , which depend on the warm gases to rise.
This has the potential for backdrafting, whether or not you detected a problem at time of inspection.

If it's spitting?? out warm air, that will continue to rise would it not?
The warm air coming out of these turbines is not exactly moving at a high rate of speed. Put your hand around one and you are not going to feel a whole lot of air movement. You make it sound as though the volume of air coming out is great, and it is not. It is mostly rising warm air from the convection effect, and it is not exactly spitting out.
They really don't move very much more air than a static ridge vent would. You could wrap some wire around one to stop it from spinning, and it would still vent heated air.
You would likely get more backdrafting from a kitchen or bathroom exhaust fan than one of these.

[Joe Farsetta]

Bob,

This has the potential for backdrafting, whether or not you detected a problem at time of inspection.

I think there is probably less turbulance caused by these units than natural turbulance and pressure found on a typical windy day, so I do not necessarily agree with your analysis. They are not made to "spit" out anything. They rely on simple convection to turn the turbine and assist with attic venting.

But... the initial question was whether the furnace flue was installed correctly.

The answer may be a resounding yes.

If you perceive a problem with the current configuration, then you need to state that you believe the updraft from the turbine may interfere with the venting of the flue gas (creating a backdraft), based on their close proximity to one another. This is, I think, a stretch. But, you have a concern, so by all means include it in your report.

However, absent of knowing what was installed first, you would be incorrect in stating that the furnace flue is installed incorrectly, based on ANY code.

The problem may have been created when the turbine was installed. You perceive a problem exists, and that is somewhat questionable as to the actual mechanics involved.

I would simply state that a possible problem exists between the two devices, e.g.: you are concerned about the possible consequences of the backdraft created by the turbine, and that it was installed without regard for current fuel-gas regulations pertaining to the proximity and height of devices installed near flue vents.

[relliott]

Originally Posted by jhugenroth

If it's spitting?? out warm air, that will continue to rise would it not?
The warm air coming out of these turbines is not exactly moving at a high rate of speed. Put your hand around one and you are not going to feel a whole lot of air movement. You make it sound as though the volume of air coming out is great, and it is not. It is mostly rising warm air from the convection effect, and it is not exactly spitting out.
They really don't move very much more air than a static ridge vent would. You could wrap some wire around one to stop it from spinning, and it would still vent heated air.
You would likely get more backdrafting from a kitchen or bathroom exhaust fan than one of these.

Maybe and maybe not.

It depends on the conditions.

If it is backdrafting ,even the smallest amount it is still a problem.
Better to err on the side of safety and call out the possibility , than pretend it is ok without knowing.

How about the 10-2-3 rule
What if the chimney is only 18 inches tall and seems to be ok.I bet everyone writes that up.
May not be a problem that you can see.

Our job is to be cautious.

[Joe Farsetta]

Our job is to be cautious.

Yes. Our job is to be accurate, as well

[Joe Funderburk, CMI]

Originally Posted by jhugenroth

The warm air coming out of these turbines is not exactly moving at a high rate of speed. Put your hand around one and you are not going to feel a whole lot of air movement. You make it sound as though the volume of air coming out is great, and it is not. It is mostly rising warm air from the convection effect, and it is not exactly spitting out.

I agree there isn't a great volume of air coming out of these vents unless there is some wind. The vent is designed like a turbine to catch the wind. The force spinning the turbine is more external wind than convection. The wind spins it and the spinning sucks out warm air. My recollection is that if there is no wind, it doesn't do much spinning. My point is that the wind spinning the turbine is the same wind that all B-vents encounter.

[relliott]

I would like to find a definitive answer , and now I have a hair up my crack.

I am suprised this subject is not more clear cut.

[Joe Hugenroth]

Originally Posted by jfunderburk

My point is that the wind spinning the turbine is the same wind that all B-vents encounter.

Exactly. If the wind is blowing hard enough to spin the turbine, there would be turbulence around the b-vent anyway, with or without a turbine close by.

[relliott]

It is not about wind.
It is about warmer attic air causing a lose of bouncy in the flue gas.

[Joe Farsetta]

Bob,

It is about warmer attic air causing a lose of bouncy in the flue gas.

Youve got to be kidding...

We are home inspectors and not mechanical engineers. I am surprised at the lack of flexibility in you seeking a "definitive" answer to this loaded question.

Look at it this way: you have a hypothesis. My advice is to go with it. If a mechanical engineer comes along and states that you are full of crap, then live with it.

My own opinion stands. That is, and since you seem to be hung up on code compliance, your question is flawed. If the flue installation pre-dates the turbine installation, then the flue is compliant. Without knowing a sequence of installation, one can not render an definitive answer. The answer you seek is a simple yes or no. I state this for the following reason: if the dwelling has a certificate of occupancy then the AHJ has/had inspected and blessed the installation.

Point it out as a concern and move on.

[relliott]

Joe you need to read before you post, as I said to point it out and never mentioned code.
The poster above me (Joe H) stated it was about wind turbulance.
We are discussing theory (sorry if this irratated you this morning).

There should be a solid reason behind the charts ,as they do not just make this stuff up you know.