Carbon monoxide detector & natural gas

Factual Questions
1

I installed a carbon monoxide detector in my home for the obvious safety reasons. My house is centrally heated by burning natural gas. Apparently, at some point enough gas escaped from the unit unburned that one morning I could smell the gas inside the house and shut the system off. It wasn’t much gas that went into the house, but just a little bit is quite noticable due to the smell they put in the gas to make it obvious. I don’t think the actual heater came on for more than a few minutes.

After shutting off the heating system, I let the blower run to disapate the fumes and odor from the house. After a few minutes the gas smell was gone and all was well. About 15 minutes later, the carbon monoxide detector went off and continued to beep for some time. I know carbon monoxide is odorless, but I do not believe there was any significant carbon monoxide present in the house.

I think the natural gas in the air set it off. I don’t think it went off right away when the smell was bad but the detector is also designed to go off when it detects low levels over a period of time. I have had my smoke detector go off when vacuuming due to dust in the air, so I think the gas actually set off the alarm.

My question is, can natural gas set off a carbon monoxide alarm by itself? I can’t find anything on the net that says one way or the other, but I suspect there may be an expert Doper out there that knows the answer to this. Is it likely that the natural gas set off my detector in the absence of actual carbon monoxide?

2

Call a service technician now.

Gas leaks are nothing to trifle with. If the smell of gas was large enough to smell in various rooms, there is a problem. There may be a problem with the ignition/combustion sequence, or a variety of other things.

Call a service technician today. When you do, ask them if they have a “Bachrach”, or “Testo” combustion analyzer (there are other manufacturers) and ask them if they are able/qualified to do a cumbustion analasys. Also have them check the heat exchanger to make sure it hasn’t failed. Lastly, have them go through the firing “sequence of operations” a few times to make sure the flame rod isn’t dirty or “blind.”

You haven’t given us much information to diagnose what’s going on, but that’s best anyway. It’s best to have a qualified HVAC guy look at the unit. This is not the kind of thing you want to scrimp on, or figure out yourself, if you’re not already qualified for the task.