CO & my oven

Mark Hunt

I am glad you started this thread.

First, go <a href=http://www.nationalcomfortinstitute.com/Find.cfm>here</a> to see if there are any NCI certified contractors in your area. Make sure they are certified for combustion and CO. Not all of them may have experience in stoves so you may have to look around.

If you have no luck there, let me know and I'll see if Jim Davis knows of someone in your area.

Mark H

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Tom S.

Not a heating question but...

Now that I have a low level CO detector (NSI 3000), I find that my oven is pumping out CO. 30 minutes at 350* gives me readings around 20 ppm in the next room.

This is only true with the oven, not with the broiler or top burners.

I've had a look at the oven burner (removed the bottom tray of the oven compartment) and it seems to be burning with all blue flames - no yellow. I did clean up some 'ash'/burnt food from the bottom which I thought helped but I now think it is not true.

I do not have the bottom tray of the oven covered with foil (I am not blocking the air vents there).

So, I'm obviously NOT using my oven for now. I want to have another go at cleaning things, but assuming that does not help, who do I call?

Appliance repair? Will they actually test for CO or just come and look at the burner?

I'm in the Boston area if anyone has specific suggestions, but I'll take broader category suggestions as well.

Thanks in advance,

Tom S.

P.S. This is a 7 yr old whirlpool oven (digital display etc) in all other respects is in very good shape which I am hoping I do not need to replace

Tom S.

Thanks...

Mark - I will check with NCI. I am open to other suggestions in case the NCI certified person doesn't pan out.

Tom

Steamhead (in transit)

Tom, Mark's right

the worst CO I've ever seen has come from these gas-fired ovens. The first thing I checked when I got my Testo was the stove in my house. The oven was about 1150 PPM and probably had been since my grandmother bought the stove in the late 1960s. And the flame was nice and blue! It's still nice and blue, and I got it down to less than 20 PPM, air-free.

Since then I've seen a few that were much worse. I generally stop the tester when it gets to 2000 PPM or so to avoid shortening the life of the sensors. But sometimes it rises so fast I get to 2500 or so in the short time it takes to stop the Testo's pump. In all these cases, the flame was nice and blue! Maybe this is what Firedragon means when he describes a "blue dragon"...

If you strike out with appliance service companies in your area, try a heating contractor. From what I've seen, they are much more likely to have test equipment and to know how to use it.

Let us know how you did.

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Jason_15

Great thread indeed!

I had similar concerns myself, I could smell the aldehydes when I ran my oven. Just last week I had my gas boiler ripped out and replaced with oil (for other reasons). Since the stove was nearly as old as the boiler, I ripped it out and switched it to electric. At that point I figured, since I was on a roll, what the heck- I went ahead and removed my gas dryer and replaced with electric as well. Now I have all new appliances and very little worry about CO. The peace of mind is worth every penny more I'll spend on the electic bill.

[Deleted User]

Jason...

Your oil boiler can still produce CO...

Don't get to comfy with a false sense of security.

ANYTHING that has a flame WILL produce CO.

ANYTHING.

Proceed with caution.

ME

Timco

I have checked cooktops & ovens with my fyrite, and found the airband (primary air) to be too restricted. Opened the band and all straightened out. All had the pretty blue flame...

Tim

Mark Hunt

Well that's one way


to do it, although you would probably be suprised if I tested your electric oven while it was in "self-clean" mode!

Yes, electric devices can also produce CO. Any "un-burned" (or "rare" as my wife calls it) food in there will give off CO as it is heated to bake it off the surface of the oven. Same goes for the top plates. Spill some sauce on them while they are hot and you WILL get CO. Enuff to kill ya'??? No. I wonder how much, if any, CO I would get from a pan of sizzling bacon? Hmmmm.....I'll test that this Saturday when I make breakfast for the family

But I have to admit, your last statement hit home, "The peace of mind is worth every penny more I'll spend on the electic bill."

Mark H




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Mark Hunt

Pretty, blue


CO.

If I over gas an appliance, I will get a pretty, blue flame with pretty, blue CO.

If enough of the pretty, blue CO gets into the house, the occupants will also become pretty blue.

02 numbers from a digital combustion analyser will point this out very quickly.

Ovens are a PITA to work on. Talk about service UN-friendly!!!

Problem is that ovens are allowed to make 800ppm of CO unvented. You measure 800ppm from the vent and according to the code, that is within acceptable range.

Ever tried messing with the spreader sheet? That's the piece of metal that the flame hits to spread the temperature evenly in the oven. 100% impingement.

Timmie can tell you all about that nightmare.

Then, after you get the oven adjusted, you get a call from Aunt Tillie saying that Thanksgiving dinner was ruined because the turkey wasn't done in the 5 hours it used to take or that the crust on her Rhubarb pie was still "chewy" after 45 minutes @350*... "Yes Aunt Tillie, but how many people fell asleep after dinner?" (Uncle Ted don't count!)

Combustion is an amazing process. A little too much of this or a little too much of that and the whole thing turns upside down.

And it doesn't matter WHAT you're burning!

Mark H

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Mark Hunt

And


things without flame can produce VERY high CO levels.

Test a cigar!

Mark H

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Steamhead (in transit)

Not only that

but as I understand it, AGA allows, or did allow, manufacturers to test their ovens for compliance with the oven floor and flame spreader removed! So their compliance testing means nothing in real-world usage.

And, natural gas is a far less uniform product than fuel oils. Its BTU content per cubic foot and specific gravity can vary greatly. So a burner adjusted at the factory may not burn with low CO if installed in another part of the country.

My old Norge doesn't have a flame spreader, never did. Maybe that's why I got the CO so low. But even with a spreader it should still be possible to get the oven below 100 PPM air-free. I usually can, assuming the oven is clean.

And The Lovely Naoko cooks great turkey in our old Norge oven!

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Mark Hunt

Frank


You are correct.

I told Tom in an e-mail that you are the only other contractor I know of that tests stoves and ovens with a digital analyser.

That is a sad state of affairs.

The guy just wants a safe house.

Safe to HIS standards, not the standards of someone that doesn't even live there.

Mark H

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Steamhead (in transit)

I think

there are some others here on the Wall, but can't remember who at the moment. Maybe some will be at Tim's Week Straight this Feb. 27-March 3.

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Mark Hunt

Sorry if I missed someone


but I do not recall seeing them post about it.

Anyone in the Boston area that can help this person?

Mark H

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Gary Reecher

Here is a lab experiment http://www.pc.chemie.uni-siegen.de/pci/versuche/english/v44-14.html

Notice the nice pretty blue flame in frame 4. Now you know why you can not eyeball a flame.

Ron Schroeder

Update #1...

Well, I've made a few calls, with not much success. For the record:

-called the NCI certified place, but they don't work on ovens. They gave me a number of an appliance repair company

-that company said they have never had a request like this and suggested I call the gas company. I told them the gas company won't fix my appliance, just tell me it's a problem (which I know).

-called another appliance repair company who said it's usually the ignitor or valve. They don't have CO testing equipment - very expensive, hard to maintain, not much call for it etc etc. I can't blame them for that, but it doesn't necessarily help me.

I'll keep calling around.

Tom

Xc8p2dC_2

Yale

Try Yale Appliance and Electric>> big outfit south of Boston

Jason_15

You bet!

Yes. I know the oil boiler still produces CO. Now it is going up a 2-story chimney with great draft! The old gas power-vented boiler had rotted the inducer housing, which was leaking condensate and exhaust into the basement. Also, the vent termination from the old boiler was dumping it's moisture load on the side of the house making pretty ice patterns on the side of the house, killing the grass, and making green moss grow on the foundation. This is on top of electronics so unreliable that I didn't dare leave the house for a weekend for fear of a freezeup! GOOD RIDDANCE!!! The new oil boiler is the cat's butt! (good)

Ron Schroeder

Update #2 - service appt scheduled

Called Yale and they only service what they've sold.

But, the good news is that I found a local appliance repair company who does do CO testing and is coming early next week. That delay is due to my schedule, not theirs- not much I can do about it.

Will report back after their visit.

Tom

Tim_25

C/O

Tim_25

C/O

Just a reminder, we should NEVER have a gas fired range without a vented [to the outside] range hood and the appliance should never be used without the range hood turned on first.

Tim

Tom S.

Hmm...

Is that realistic? I can tell you that my (problem) range/oven is not vented to the outside. It's on an inside wall which would make it pretty hard to vent outside without a kitchen remodel.

Surely that is the ideal, which I would strive for, but am I wrong in saying it is not often reality?

Tom

Mark Hunt

Not uncommon


these days and quite often next to impossible.

Houses are never designed around the requirements of the mechanical systems.

Your situation can be addressed and the CO can be lowered IF the right person with the right equipment does the job.

Thanks Tom.

Mark H

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Rudy

The 'historical' perspective.....

Here's an article from 1877 entitled "Beware of Gas Stoves". It talks about a 'new' gas stove - without a vent... The article starts right under the photo.

http://cdl.library.cornell.edu/cgi-bin/moa/pageviewer?frames=1&coll=moa&view=50&root=/moa/manu/manu0009/&tif=00290.TIF&cite=http://cdl.library.cornell.edu/cgi-bin/moa/moa-cgi?notisid=ABS1821-0009-735

Mark Hunt

Did you write that?


How do you find this stuff????

Let's hyper-link it.

Read that one folks. Definitely a keeper!

Mark H

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Rudy

It's easy...

I have pissed away many, many hours on this "Making of America" site. Go to the search engine and type any any topic relavent to that era.

Amazing what comes up!!!

Mark Hunt

Thanks for the link


I'll have fun there!

I gotta' e-mail you what I found tonight. Sold two NSI monitors to boot!

Mark H

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Rudy

Here's another

Just type in carbonic oxid into the search engine. Here's another 'How to Kill Criminals' - CO poisoning sure beats hanging (and by the way, how do you do the hyper-link thing, still can't figure that out).

http://cdl.library.cornell.edu/cgi-bin/moa/pageviewer?frames=1&amp;coll=moa&amp;view=50&amp;root=/moa/manu/manu0010/&amp;tif=00237.TIF&amp;cite=http://cdl.library.cornell.edu/cgi-bin/moa/moa-cgi?notisid=ABS1821-0010-647

Apparently, the way to kill criminals is give them a gas oven....

Mark Hunt

Easy


Like this.

Mark H



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Rudy

Yea

Easy for you!!!

Rudy

Does this work?

> Easy for you!!!



Another

Dirk Wright

I believe that a powered vent that exits to the outside is required by code for all gas cooking appliances. I just wish that there was an easy way to interlock the appliance with the vent such that the vent turned on when the appliance was turned on. I know they do this in commercial kitchens, but have never seen it in residential.

Also, I have a propane cooktop and the flames sometimes have yellow tips. The yellow tips are not constant, but intermittant. It also doesn't seem to matter where the setting is either. I suppose it could just be contaminants in the propane of course. I have a Fyrite Pro 125 and I think I measured 40ppm over one burner with no pot on it. I don't see any adjustments outside of replacing the jets, which are the ones included with the unit intended for propane. The cooktop is a GE sealed burner type with electric spark starting. any ideas? thanks in advance!

Timco

Adjust the regulator or the air band. There is usually a little clip that slides right where the burner 'plugs in' that is the primary air adjustment. I am under the impression it should be tested with a pot of cold water, to check it under a load with the flame being cooled. As the water warms, the flame temp should rise, and give a better reading. Flame should not touch the pot. High CO is low flame temp or lack of O2, making combustion incomplete.

Tim

Henry Patterson Karis HVAC

> Easy for you!!!

D107

so rangehood vented to the outside will exhaust BOTH stove

and oven CO. i.e. there is no provision or need to attach vent from oven section? I have a microwave that includes a range hood more powerful than most--two settings 200 and 400 cfm. then you run into problem of possibly backdrafting from fireplace or elsewhere. Fresh air intake required?

I've noticed that once you go for safety you are drawn into the inevitable 'whole house integrated system' scenario where heating, AC, ventilation, insulation, air-sealing, humidification, purification AND alarm systems, etc. need to work together. And this knowledge rarely resides in a single contractor, so a homeowner has to do exhaustive research in a field that is changing daily. e.g. building science.com, the wall, etc.

wish i'd be around to see what a smart house would look like in a hundred years.

Ken D.

CO

A customer of ours is a semi-retired baker. I got a call that his CO detector was dancing off the wall. My Bacharach read over 200 ppm. Furnace was ok. Problem was he would bake 120 loaves of Italian bread in a huge commercial oven in his basement every morning to earn extra cash. No exhaust hood or fresh air intake. He got the hood and intake and no more problems.

Steamhead (in transit)

That's how I test top burners

with a pan of cold water and the probe just underneath the side of the pan, to test under conditions of actual use. If set up properly, it will spike at up to 150 PPM or so at the moment of light-off and then drop like a stone.

Many stoves also have adjustable orifices, which you can turn down if needed to keep the flame from impinging on the pan at high fire.

I like to do the oven first, then the top. This lets me adjust the air shutters on the top burners so the flames won't lift off the burners when the oven is hot.

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Constantin

Hear Hear...

On the other hand, if you're going to live in a place, it kinda behoves you to figure out what you, why you want it, and how to find the people to make it that way. For our project, I spent several months coming up with specs, etc. before choosing contractors because I wanted to find one that cared as much about the house as I did.

Was every sub-contractor on the same page as I all the time? Of course not. We're all human and we have expectations ingrained from past experiences. For example, our HVAC sub wanted to install 7 tons of AC capacity because his working assumption was 96&Deg;F exterior, 70°F interior conditions. Well, my wife and I can't stand anything under 74°F and the trees around the house will limit most of the insolation. Most likely, we'll stay below the 5 tons that we installed 99% of the time, if not more.

Being a good contractor and coming around to my line of reasoning, the HVAC guys installed the smaller system. I wish the local FD would take a page from them, i.e. be wiling to interact with "customers" instead of just dictating to them and hoping that they won't notice the difference between fiction and reality.

Guy_6

Grandma

Grandma's gas oven had this shiny, 3 inch pipe coming up from behind and exiting out the wall. Hmmm- did the old timers know something that we are missing? Perhaps that burning (anything) creates , well, STUFF (they knew that it wasn't GOOD STUFF) that they didn't want in their homes. Either that or Grandma had a habit of burning the muffins too often...

D107

so where would fresh air intake be for stove in residence?

seems that you wouldn't want it in the kitchen--too much cold winter air right at you or upsetting the gas flames. (rem. range hood exhaust 200-400 cfm fan above stove at microwave bottom venting to outside behind microwave).

David

PS Also thanks Constantin--yes ho's have no choice but to do the research ourselves and find the right contractor. Benefit is you get the job done right AND learn alot in the bargain.

Constantin

Here is how I did it...

... which does not mean it's right. Since we have an AC system, I simply tied an exterior duct with a damper into the AC return. Whenever the hood vent is turned on, the duct damper opens, and air can flow. When the hood is turned off, the damper closes.

My HVAC contractor put some strip heaters into the AC system to pre-heat the incoming air. I will disable that feature if testing shows it's not needed.