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leland #174966 02/18/08 05:01 PM
Joined: Jun 2003
Posts: 1,143
Had an odd problem like this at the FD once (then later at my own house).

The 2nd floor smokes were fed by a conduit run that enetered the attic space and went above the insulation. It then re-entered the living area.

Seems the airflow was just enough to allow condensation to form and trickle into the back of the detector, causing them to sound for no reason. Removing the detector from the circuit (of course) enabled the other to function, and revealed evidence that it had been happening for a while (rust traces).

I've since heard of EC's using a dab of firecaulk or a shot of spray foam in the pipe entrance to prevent this occurrence.

DougW #174969 02/18/08 06:29 PM
Joined: Jul 2007
Posts: 1,335
Sounds like a band-aid fix for a bigger problem

"Live Awesome!" - Kevin Carosa
Joined: Feb 2003
Posts: 687
Ya that is sometimes a problem. You would think if all the pipe runs end in a heated space and you keep the pipes at the joist level it would not happen, but it does. Used duct seal on the pipes. Also moved insulation over the EMT in the atic. Realy I think is is more of an insulation in the atic issue in most cases. Have herd the ideal solution is to have the pipes go in the side of the box not the top. Maybe that would work if you could keep the pipe at the bottom of the joist deep in the insulation. Some smokes have a gasket to prevent airflow. But it still happens. Maybe a bit of fiberglass insulation in the J-bx.

The worst is when there was a problem but have no idea which one of the 10 or so devices caused it. I wish the SD would have a resetable indicator to show if that perticular one was triped.

Just herd today FireX recall on CO detectors.

Joined: Feb 2003
Posts: 687
Do like me. Have the smoke hang by the wires. Then if it goes off hit it like a piƱata.

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