Originally Posted By: jonofrey This post was automatically imported from our archived forum.
This gas vent termination seems wrong to me but I’m having some trouble translating the IRC. This is not a mechanical draft system so I’m thinking that it should comply with G2426.6.5 (503.6.6) which it appears it does. The vent pipe does terminate above the roof surface but it’s just laying there in the vent hood.
Originally Posted By: nlewis This post was automatically imported from our archived forum.
John,
The vent should definitely go directly through the roof and not terminate in the hood area. Also, that looks like single wall pipe. It should be double wall, such as b-vent, in an attic area.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
John,
Any vent connector/chimney that is carrying carbon monoxide from a heat source should terminate to outside air.
Also, The chimney outside must extend 3 feet from the point of penetration through the roof. The top of the chimney must be at least 2 feet higher than anything within 10 feet of it.
Hope this helps! 
Originally Posted By: jonofrey This post was automatically imported from our archived forum.
Dave,
After looking at the IRC more closely, I think your right. Intially, I thought you may have been confusing fireplace chimneys with gas vents but I now see that the 2 in 10 and 3 foot rule seems to apply 
Originally Posted By: dvalley This post was automatically imported from our archived forum.
John,
Yes, Gas venting appliance clearances apply the sames rules as chimneys.
They are all poisonous gases and must vent to the outsde in the same manner.
The first pic that you have here is definately a red flag. The carbon monoxide that is trying to exit the building has a tendency to re-enter the area by wind forcing it right back down alongside the vent hood. Now the gases are in the living area verses the vent connector.
Ready, 1-2-3 Breath. Not good. 
Originally Posted By: jonofrey This post was automatically imported from our archived forum.
I am glad I went through this excersize with you guys. It’s clear to me that the gas vent pipe needs to penetrate through the roof, flashing and jack without interruption to a minimum of two feet above the highest point of penetration. Anything else will raise a red flag with me from now on.
Flue is definitely above the roof line. Some one thought it would be great to install a metal faux fireplace chimney around it. Extension and weather hood totally missing. Metal rusted away on the cap and flashing problem.
Results, not only water in the attic, but CO back drafting into the attic space
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Quote:
If the gas appliance is burning properly, carbon monoxide is not being produced.
What is up with that? Are we all on the same page here? Did I miss something in GAS APPLIANCES 101? 
Originally Posted By: dvalley This post was automatically imported from our archived forum.
Neal,
If carbon monoxide is not exiting through the chimney/vent connector, could you please fill me in on what is venting through this?
I must have missed some important info from my heating textbook.
Is it air?
Is it carbon dioxide?
Is it flames?]
Originally Posted By: arosenbaum This post was automatically imported from our archived forum.
nlewis wrote:
David,
If the gas appliance is burning properly, carbon monoxide is not being produced.
Not trying to be a smarta**, but when you have car in your garage and you start it up..... you need the garage door open.... because if you let it run for 5+ minutes without the garage door open, you're in trouble 
Originally Posted By: nlewis This post was automatically imported from our archived forum.
Well I could be wrong, but I have read that CO is produced only during incomplete combustion of a gas fired appliance.This is from info at the Bacharach and COexperts websites as well as others.
As a test , tonight I disconnected the flue from my nat gas water heater and detected no CO with my Bacharach Snifit. I know it is working because just the other day I checked the vent from my electric stove during the self clean cycle, and sure enough I was getting readings of up to 50 ppm.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Neal,
They said the same thing about those ventless gas fireplaces. When I put the snifit up to the fireplace, it was glowing with CO. Matter of fact, it went well over 100 PPM and maintained that reading for all of the five minutes that I left it burn. Guess it does not work for ventless models! 
Originally Posted By: kluce This post was automatically imported from our archived forum.
In N/W indiana, when I did testing for the county, I was allowed to have up to 25 ppm from each gas burner on a stove. Anything more than that needed to be corrected or replaced.
He is right, when fosel fuel burns perfect, there is no CO. BUT most thing don't burn perfect. Dirt or design is the main reason in my book.
My book refers to my thinking. 
There is an oil furnace that is made- but not sold -that is ventless.
I would never want it.
Originally Posted By: rmeyers This post was automatically imported from our archived forum.
combustion. The key word being “incomplete”.
It was called to my attention years ago when I purchased my first CO detector, (to help check for cracked heat exchangers), that if the combustion process was operating efficiently, CO would not necessarily be present in detectable amounts which would indicate a cracked exchanger.
I use my CO detector to check for unsafe conditions in the residence, but not to evaluate the condition of a piece of equipment. I refer the technical evaluations to those with the expertise. They can then disassemble the unit and perform an appropriate inspection of the heat exchanger, (or appliance in question).
I am not a big fan of the ventless heaters and fireplaces for the reasons expressed earlier. Most are not functioning efficiently after only limited use and often present safety problems. Not to mention the excessive amounts of moisture often introduced into the residence with ventless heaters.
Originally Posted By: gbeaumont This post was automatically imported from our archived forum.
Hi kevin,
I suspect that Neil posted that to trip up the unaware, you are quite correct that CO production is normally a by product of incomplete combustion within a focil fueled appliance.
However, when you put any oven into its self clean cycle, it heats up to a temperature at which any food/grease exetera is “burnt” off the inner surfaces at this point the smoking remains of last weeks roast are producing Carbon Monoxide as they are not being completely combusted.
I’ll have to check that out on my electric stove.