coalkirk wrote:While sitting in my family room this evening, I started to smell flue gas from my coal boiler. The coal boiler is vented in an 8" square terra cotta flue in a brick chimney. In the same chimney is a 12" flue for the family room fireplace. I was getting a down draft down the fireplace flue because of the warmer temps, rain and low barometric pressure. It was a faint odor but I stuck my co detector on the hearth at the fireplace and with a minute it was rising fast to almost 200. I didn't wait to see how high it was going to go. I opened all the windows and it dropped within a minute. The fireplace damper was closed but they are not air tight. So I climbed out on the roof in the rain with a piece of aluminum foil, removed the chimney cap on the fireplace flue, covered it with aluminum floil and reinstalled the cap. Problem solved for now.
It's not only a problem with the level at which the CO detector sounds it's the reliability of the CO sensor itself. I'm not taking about the entire instrument but the tiny sensor within the instrument that converts CO gas to electrons. There are only two companies (FIGARO ENGINEERING and MST Technology GmbH) worldwide that make consumer level CO sensors and they are not very good. There is a large variation in unit to unit sensitivity and a short overall lifetime. Your CO detector is just about worthless for reliability detecting the level of CO that can harm you 5 years after first being manufactured. I've collected a lot of engineering info on the subject and when I get time I'll post my findings. What's needed is a simple test to verify the functioning of your CO detector. I'm thinking something like putting the CO detector in an enclosed box with a burning candle and timing how long it takes to go off. Any combustion chemists on this forum that can calculate the CO produced by a candle and provide a CO concentration vs. time graph for a specific enclosed volume?coalkirk wrote:Thanks for all the replys. I've got three CO dectectors, one on each level so if it had gotton really bad, I would have at least been alerted. I rememebr a post by Yance awhile ago about the threshold it takes for these damn things to sound. I'm going to go back and reread that today.
coalkirk wrote:I really like the look they give also. Might not work archetecutrially on my home though. check out these copper chimney caps.
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