Heat, light, sound.

January 2, 2013 10:24 PM

Why does my heater make my apartment smell smoky?

I live in a small apartment in central Texas. Earlier today, the heater was running, albeit very loudly. Tonight, I set the thermostat and went out to dinner. When I returned, three and a half hours later, the apartment was hazy and smelled of smoke. I immediately turned the heater off and opened windows. There were no signs of fire, and the haze cleared quickly. After an hour or so, my curiosity got the better of me and I turned the heat back on to try to troubleshoot the problem. The electric AC/heater combo unit made a very loud shuddering noise, not unlike a stalling engine, so I immediately switched the unit off again and flipped the breaker leading to it off.

I am safe and planning on monitoring the situation for a few more hours before I go to bed, have a working smoke detector, and am not feeling ill. My question: what happened? Did the motor in the AC/heater unit fail, causing smoke to be fanned thru the apartment? Should I crash at a friend's place? Obviously, I will be calling my landlord to send a technician tomorrow, but I'm curious about what happened.

posted by thack3r to Home & Garden (7 answers total)

Do you have a fireplace? Is the flue open?
posted by mr_roboto at 10:59 PM on January 2, 2013

Response by poster: I have a fireplace; the flue is closed. Also, the complex is pretty empty right now, I don't think anyone has a fire going.
posted by thack3r at 11:22 PM on January 2, 2013

Best answer: I've never actually taken apart a combo heater / AC unit, but I assume the heater part of it is basically a giant hairdryer, i.e. a heating element and a fan. Two potential causes that I can immediately think of are a failing fan, causing the heating element to overheat and begin to fry some internal part of the unit, and dust having settled on the heating element during the off season. Was this the first time you've used the heater this year? Was the apartment remodeled recently (drywall dust, etc.)?
posted by jon1270 at 2:20 AM on January 3, 2013

Some furnace layouts have the filter placed extremely close to the blower fan, and if the filter gets sufficiently dirty, the suction can bow the filter inward far enough for it to make contact with moving parts, or even to become detached and obstruct the fan. Either way, it can result in a fire. Just one of many possibilities, but the shuddering sound made me think of it.
posted by gimli at 6:27 AM on January 3, 2013

Not sure of the shuddering sound, but if you're not familiar with electric heat, the first time or two that you turn it on for the season, it can put out a pretty intense smell of burning dust; the dust accumulates in AC season, and burns off when you crank up the heat. If you're not getting good airflow across the elements due to a faulty fan or plugged filter, this could be a safety problem.
posted by Doohickie at 7:13 AM on January 3, 2013

Best answer: It sounds like the blower has gone out of balance and will need to be replaced. But that's just a guess.
posted by gjc at 5:22 AM on January 4, 2013

Response by poster: HVAC tech just came over, deftly took the unit apart, and showed me all the twisted blower louvers that were caught in the heating coils--the blower fan came apart, the motor bearing took some damage spinning the unbalanced fan at high speed, and the heating coils were damaged by flying pieces of metal from the fan. Thanks for your help!
posted by thack3r at 10:40 AM on January 4, 2013