When doing a combustion

Tim McElwain

test on a boiler or furnace should a test also be done on other appliances?



Would you test a gas cooking oven on a gas range?



Does a gas dryer in the combustion zone present any particular attention?

Plumdog_2

All of the above!

1 I think you should check all gas burners. I would pay attention to Gas Fireplaces, as sometimes they leak CO from the seals, even though they are supposed to be "Direct Vent", and the levels can be very high, as they are "Decorative".

2 Ovens are often way out of proper adjustment. They can be checked at the vents near the rear of the cooktop.

3 Gas Dryers, even when properly vented, tend to create lint conditions in near proximity, which will clog primary air intakes on atmospheric burners, as well as Combustion Air Intake screens on FVIR water heaters. Not to mention creating slight negative pressure conditions in the mechanical room. 

KCA_2

I usually

go around with a gas leak detector...  Check for gas leaks at the cook top, fireplaces, dryer and whatever....  But a combustion analysis?  On a cook top?



  :-)  KCA

Steamhead

Of Course!

The best way I've found to test a stove top is to put a pot of water on the burner, then turn the burner on and hold your analyzer probe at the outer edge of the bottom where it can pick up the combustion products before they get too diluted. Sometimes I have to offset the pot on the burner to keep the flame from getting too close to the probe and overheating it. This method tests the burners under conditions of actual use.



If you get high CO on a top burner, it's usually because the flame is too high and is impinging on the pot. This is easy to correct if the stove has hooded orifices or other limiting devices that can be turned down. If there are adjustable air shutters, in general they should be open as far as possible without causing the flame to lift off the burner. You want as much primary air as possible to keep the length of the flame as short as you can.



Most oven and broiler burners I've seen have hooded orifices, even if the top burners don't. Same thing applies here- air shutter open as far as possible without lifting the flame, then regulate the flame height with the orifice to keep it from impinging too much. Most times I end up with the shutter wide open on ovens and broilers. I've seen ovens putting out over 2000 PPM CO, and apparently they had been for years. This is scary- and so easy to fix.



If the oven or broiler needs cleaning, that can also cause high CO.



I'm sure Tim and others will weigh in here, but this has worked for me.

Charles Johnson

All of the above

All of the above is correct!



I have found several ovens producing high levels of CO, over 1,000 ppm. No combustion appliance should be overlooked.