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On November 30, I changed our pleated furnace filter (Bryant furnace - 23 yrs old) and noticed that it was a dark color (blackened) and didn't think too much about it as the filter hadn't been changed for a couple months. That was the first time seeing the filter that color. Today, I checked the filter and it was blackened again so I Googled this situation and a response was possible cracked heat exchanger; backdraft or from burning candles (soot causing the issue). Lately, we have done the latter. In September 2015, we had purchased the condo and had the furnace thoroughly checked with no issues indicated. Anyone have such an issue.
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Do you have a CO detector ? If not get one. If it is a cracked heat exchanger it can let CO in the house. Assuming it is a gas furnace check by the flue and see if there is a back draft down the flue when ether the furnace or the water heater is running. If everything checks out stop burning candles for a while and check the filter in a couple of weeks. Roly
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Thanks for the reply Roly. It is a NG furnace and we have a CO detector in the furnace room. I'll check the flue on it and the NG water heater to see if any backdraft is occuring.
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Assuming the CO detector is working, the candles are most likely the cause as the back draft would set off the CO detector. Normally there is a lot discoloring on the outside of the furnace where the combustion air enters if it is back drafting. Roly
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First off, specifically which furnace model? At that age I would expect it to have a spill switch that would lock it out if there was a backdraft. How many times have you changed filters in the year you've been there? Always used the same filters? Some filters show a very marked colour change as they load up, others not so much. The culprit is very likely the candles but let's look around a bit.
Blackhat
Bad experiences come from poor decisions. So do good stories.
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(12-24-2016, 11:09 AM)Roly Wrote: Assuming the CO detector is working, the candles are most likely the cause as the back draft would set off the CO detector. Normally there is a lot discoloring on the outside of the furnace where the combustion air enters if it is back drafting. Roly
Yup most likely it's from the candles. candles leave lots of nasty residue in houses. They will also leave soot on the ceilings and walls and sometimes it will attract where the cceiling joists are.
Best thing is not to have open flames in the house with the gas stove being the exception. I told loml a long time ago no candles.
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Hi Blackhat,
We have a Bryant furnace and I've tried to to maintain a two month interval to change the furnace filter. On November 18, we had our NG water heater changed and it was at the end of November that I noticed the blackened furnace filter and again today. The gas inspector came just before the end of November to do the installation inspection on the water heater and did mention that the slope of exhaust piping from the water heater to the chimney was not sloped enough and he did some adjusting on the elbow to improve the slope. I've read on other sites this morning that moisture (rusting) on the top of water heaters can be the result of backdrafting so I'm thinking the venting of the water heater is not correct. Our old water heater (3 years old) had rust occurring on the the top so we had it replaced under warranty last month. I plan to have the installation plumber come net week to check the situation out. As far as candle burning, we have not much of that since November.
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I've already had two calls this month about sudden black filters. My first question is "Are you burning candles"? All answered yes- for Christmas.
After a while, you will notice black lines along doorstops and the carpeting at the bottom of doors kept closed. Sometimes, with excessive candle or lantern burning, the registers on the ceiling as well as the ceiling will begin to darken.
It also gets into your lungs. Carbon soot.
You might try a healthier candle.
http://www.pureintegrity.com/soot-free-candles.html
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What is the combustion air supply to the furnace space? Is it partially blocked? Here's an old trick. Stick a couple pieces of masking tape on top of the water heater, a couple inches away from the edge of the draft hood. Scrape some shavings from a wax crayon or coloured candle onto the tape. Watch while the water heater and furnace are running. Melting wax means combustion products are spilling from the hood.
Blackhat
Bad experiences come from poor decisions. So do good stories.
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have you had the furnace serviced lately? the tech can run a combustion test to make sure everything is properly tuned.
