Thread: Kitchen Range

My gas sniffer picked up a gas leak at the upper vent on this older kitchen range.
I couldn't smell any gas at all with my nose, but it definitely lit up the Leakator.

Is this a natural gas leak, or another by product of the combustion inside the oven?
I don't normally sniff around this spot when the oven is on, but maybe I should be.

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A combustion analyzer will give you a lot more information from that vent collar than the leakator.

I would trust my built in gas detector (nose), before an electronic sniffer. Yes, I use to have one as just about every new home inspector. They are very very sensitive and will produce false positive readings. Your breath will cause some to start alarming. I even had them go off at high concentrations of CO when a device was fired up.

The area you tested looks like the vent for the oven. If the oven was just turned on it could be from the left over gas or high CO.

If you did not smell it with your God given detector, I would not worry about it. But since you posted this on a public board that everyone can see, you might want to make note of it in your report!

You can make them scream with a properly timed wave of the sensor behind you after a gaseous discharge event.

Now I know why they pay you the big bucks Jerry! Laughing GAs!

There may be a standing pilot for the oven that the detector was picking up.

Originally Posted by Scott Dana

There may be a standing pilot for the oven that the detector was picking up.

You can see the piezo igniters on the burners, the oven will have that as well.

"MY" gas leaks can usually be found in the attic. For some reason, they always want to manifest as a full-vaporopus apparition and scare the client when they come up (scare me too sometimes )

Client: "My god, is that gas I smell"

Me: "Yuup" -- let's get outta here...

CO is not a hydrocarbon. No hydrogen in it--just C & O. Those sniffers Will pick up aldehydes such as paraldehyde and acetyladehyde.

If this unit is LP, it can hold unbured gas for a long time after it was cycled off.

Needs to be inspected closely by a qualified technician who has a combustion analyzer and knows what to do with it. Yes, ANSI stds allow 800 ppm from gas ranges. And you just thought it was the tryptophan from the turkey making you sleepy at Thanksgiving!

If you are interested in the gases a leakator will detect take a look at Bacharachs site.
They have a full list of the gases it will alarm to.

A good CO2 detector will run you over a grand easy doubt it is that, combustion analyzers don't even measure that value they calculate it.

One good reason to ignore the CO2 reading on a analyzer.

Another indirect CO2 reading using a combustion analyzer is to hold it near the floor and read the O2. If it drops much below the 20.9% norm, you have to ask yourself is this CO2 displacing O2 as it settles near the floor. Now, if you ambient O2 is dropping, you will start getting incomplete combustion and making Bad Stuff, which the analyzer will pick up. Just goes to part of the whole picture.

BTW, analyzers are pumps that draw in room air from several feet whereas sniffers must be placed into the vapor cloud or it will give a false negative. I agree w/ David that Bacharach's Training Room is a good primer.
HTH
Bob

Another indirect CO2 reading using a combustion analyzer is to hold it near the floor and read the O2. If it drops much below the 20.9% norm, you have to ask yourself is this CO2 displacing O2 as it settles near the floor. Now, if you ambient O2 is dropping, you will start getting incomplete combustion and making Bad Stuff, which the analyzer will pick up. Just goes to part of the whole picture.

Sniffers are notorious for false positives. I've picked up a hit that turned out to be formaldehyde offgassing from wet insulation. I have also found a CO leak when it picked up on the aldehydes so I ran and got my analyzer and sure enough, CO! Most sniffers will hit on soap bubble test solutions so sniff then bubble (non-corrosive only).

BTW, analyzers are pumps that draw in room air from several feet whereas sniffers must be placed into the vapor cloud or it will give a false negative. I agree w/ David that Bacharach's Training Room is a good primer.
HTH
Bob

Originally Posted by Bob Harper

Another indirect CO2 reading using a combustion analyzer is to hold it near the floor and read the O2. If it drops much below the 20.9% norm, you have to ask yourself is this CO2 displacing O2 as it settles near the floor. Now, if you ambient O2 is dropping, you will start getting incomplete combustion and making Bad Stuff, which the analyzer will pick up. Just goes to part of the whole picture.

Great advice Bob!

This is also a great trick to use in the burner compartments of appliances, there should be nothing but close to 20.9% O2 being fed to the burners.

If the burner compartment reads less than that you need to start looking at possible CO2 displacement issues in the burner compartment.

Temperature measurements work well for this also.