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Thread: smoke detector

  1. #1

    smoke detector

    smoke detector installation on supply air lennox package unit. 10 ton. instructions only show where it should be but AND THIS IS A BIG BUT! I dont see any screw holes for the brackets. Shows installed between the squirrel cage and the coil. but cant seem to see any way to install the bracket without making my own holes. doesnt seem right.

  2. #2
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    We always used a shop fabricated bracket and mounted it as best we could to be in the correct location and secure. It actually worked good, the braket was just a 90degr angle with sides and we put the template on it and mounted away to the floor of the cabinet. Also the detector must be upstream of any fresh air or make up air by code. So this location cant be used if your duct system uses any of these, it will have to be duct mounted. As long as it is in the airstream and the sample tube is oriented correctly it really doesnt matter exactly where, and as far as the manufacturer its more an afterthough and they problably didnt allow for it in the design and therfore no holes.

  3. #3
    duct mounted? I have brackets that came with the unit seems pretty right on with the actuator. unit instructions show it in the unit between coil and fan. Duct mounted would be easy but i think these just plug into the unit and have to be installed within the amount of wire it has. plug and play. there is somthing i am missing

  4. #4
    Quote Originally Posted by stickinit2thman View Post
    We always used a shop fabricated bracket and mounted it as best we could to be in the correct location and secure. It actually worked good, the braket was just a 90degr angle with sides and we put the template on it and mounted away to the floor of the cabinet. Also the detector must be upstream of any fresh air or make up air by code. So this location cant be used if your duct system uses any of these, it will have to be duct mounted. As long as it is in the airstream and the sample tube is oriented correctly it really doesnt matter exactly where, and as far as the manufacturer its more an afterthough and they problably didnt allow for it in the design and therfore no holes.
    sorry didnt read your entire post. So just screw it into the cabinet floor with the brackets and call it good. Just as long as the air tubes are positioned the right way?

  5. #5
    Join Date
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    Quote Originally Posted by sheetmetalwannabe View Post
    sorry didnt read your entire post. So just screw it into the cabinet floor with the brackets and call it good. Just as long as the air tubes are positioned the right way?
    Thats the way weve done them here for years. As long as its in the correct location in the cabinet as the install instructions say then yes the tube hole need to be a certain way in relation to airflow(one is inflow and one outflow)If I remember correctly (its been a few years but ill check with my duct running buddy)the long is in and the short is out?the instruction will tell ya, and you are fine, is it a manufacturer supplied detector? Thats what it sounds like if it has molex type plug. We always had aftermarket so to speak(Manufactured by company other than manuf.) and could mount them in the unit (with fabed bracket) or on the side of rectangular duct with holes for sampling tubes and were field wired. They could be powered by 24-v or 120-v so guess who got stuck with wiring them when the electritions learned that! But anyway as long as its sampling you are fine IF your local codes allow it! In this case check the instructions and see if they can be remotely mounted and field wired.

  6. #6
    Thanks stickit2theman
    Just needed some reassurance just screwed the bracket to the blower cabinet between the blower and the coil. Still seems like it should have factory mounting holes. Wiring harness was the right length to the control box. That hurdle is done now onto the reznors.
    Thanks again for your input

  7. #7
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    Quote Originally Posted by sheetmetalwannabe View Post
    Thanks stickit2theman
    Just needed some reassurance just screwed the bracket to the blower cabinet between the blower and the coil. Still seems like it should have factory mounting holes. Wiring harness was the right length to the control box. That hurdle is done now onto the reznors.
    Thanks again for your input
    Glad to help

  8. #8
    Join Date
    Oct 2009
    Location
    new jersey
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    Iv seen them mounted in lennox 10 ton in return door by filters.

  9. #9
    Quote Originally Posted by dave sulz View Post
    Iv seen them mounted in lennox 10 ton in return door by filters.
    Ra would be easy mounting holes and everthing . Sa is little bit different they (the man) speced sa duct smokes. Doesn't make sense to me either especially when it's full outside air

  10. #10
    Join Date
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    Landis North Carolina
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    Quote Originally Posted by dave sulz View Post
    Iv seen them mounted in lennox 10 ton in return door by filters.
    The main point to remember when installing duct/unit mounted smoke detectors is that they cant be mounted where they sample any outside/makeup air and they must monitor/sample the entire return duct system(make shure its between the fan and last return tap/takeoff before unit) and also before the filters. This way entire system is monitored and there is no chance of any outdoor smoke can be sampled and cause nuisance shut downs. If there are economizers or makeup air intakes at unit then the detector must be duct mounted! Or nuisence shutdowns are likely to occur, not to mention most codes will not allow it.Hope this helps for future installs. I spent many years doing commercial installs and the last 5-6 on install crews with electrical/plumbing crews(we called them piping&wiring crews) And as part of our many responsibilities was to install and wire all duct/equipment smoke detectors. Its been almost 10years since ive done installs on commercail exclusively. Still do them occaisionally, but I have never heard of a manufacturer supplied detector that just plugged in. That makes it pretty straight forward with less hassell. See ya

  11. #11
    Quote Originally Posted by stickinit2thman View Post
    The main point to remember when installing duct/unit mounted smoke detectors is that they cant be mounted where they sample any outside/makeup air and they must monitor/sample the entire return duct system(make shure its between the fan and last return tap/takeoff before unit) and also before the filters. This way entire system is monitored and there is no chance of any outdoor smoke can be sampled and cause nuisance shut downs. If there are economizers or makeup air intakes at unit then the detector must be duct mounted! Or nuisence shutdowns are likely to occur, not to mention most codes will not allow it.Hope this helps for future installs. I spent many years doing commercial installs and the last 5-6 on install crews with electrical/plumbing crews(we called them piping&wiring crews) And as part of our many responsibilities was to install and wire all duct/equipment smoke detectors. Its been almost 10years since ive done installs on commercail exclusively. Still do them occaisionally, but I have never heard of a manufacturer supplied detector that just plugged in. That makes it pretty straight forward with less hassell. See ya
    It was just a plug and play. Controls co confirmed it. Your piping and wiring crew ever deal with a controls co?

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