Air Handler in the attic Question

Discussion in 'HVAC' started by drewdin, Apr 12, 2013.

  1. Apr 12, 2013 #1

    drewdin

    drewdin

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    There coming monday to install an Air handler in the attic of my house, right now there is no insulation up there.

    I know once its installed, there will never be any insulation under it so I plan on buying some along with a sheet of wood and making a platform for it.

    Does anyone have any other recommendations? How much should I put there? Should I even do it? Thanks
     
  2. Apr 12, 2013 #2

    nealtw

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    A buddy of mine has that, they put it right on the ceiling joists and then put in loose insulation all around it. The insulation gets into the overflow trey and plugs the pipe. It has to be serviced and they have no catwalk to walk on and nowhere to stand when servicing and when they come down thru the closet they bring insulation with them, so they they have to drap plastic over the clothes first.
    So I would say yes.
     
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  3. Apr 12, 2013 #3

    bud16415

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    My suggestion would be talking to them first. That is the guys installing the air handler. They may have a system of mounting it already in the works or then again they might not and welcome your idea.

    I think nealtw’s suggestions are all great and a catwalk is very nice to have above your insulation. Depending on how it is framed and where you live the framing might be less than the thickness of insulation you will want and things will have to be framed up.

    It’s a good idea just make sure you think it thru till the end first.
     
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  4. Apr 12, 2013 #4

    CallMeVilla

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    Rigid insulation is an option below and around the handler in the joist bay. I would certainly provide a plywood platform and plywood from the access to the handler for servicing.

    Just got out of an attic electrical install where there was one piece of plywood to slide around so I could work on electrical. It sucked. :p

    Bad_electrical_work_in_the_attic.jpg
     
    Last edited: Apr 12, 2013
  5. Apr 13, 2013 #5

    kok328

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    The contractor should install large drip pan under the unit just in case the condensate pump fails.
    Rolled insulation and plywood should be installed for servicing unless you want somebody coming through your ceiling. ;)
    CallmeVilla,FYI - that J-box looks overloaded and will need a cover plate installed.
     
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  6. Apr 13, 2013 #6

    CallMeVilla

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    Hey KOK ... the photo is a real life mess ... the attic I am working on had three more nests like that which were WORSE that I had to clean up. Didn't take a photo yet of the recessed lights with the ROMEX insulation outside the light box and the wires hanging on the sharp edges of the holes without connectors.

    Oh, did I mention the back-to-back GFCIs that were in adjoining walls?? :D
     
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  7. Apr 13, 2013 #7

    drewdin

    drewdin

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    Thanks Guys, I called the contractor and he said that he plans on hanging the AHU from the joists due to the 18" of blown in insulation that will be going in this summer. I like the idea but this also make me nervous, anything I should be aware of with a hovering AHU?

    **He did say he was installing a drip pan
     
  8. Apr 14, 2013 #8

    GBR

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    As said already, you install a catwalk (per code; width) high enough to get full R-value to the unit from the scuttle hole. Cover exposed Romex within 6' of the attic access from walking on, per code. "Hanging from the joists" or maybe rafters- make sure they add additional vertical supports to a bearing wall below to carry the additional roof loads. Be sure your drywall can carry the additional insulation weight; https://docs.google.com/viewer?a=v&...xf51fE&sig=AHIEtbQixCH3AO0RugCGh3VLQNBaXp54rA

    And if plaster/lath, the ceiling joists are able to take the weight as they are already at 8#per sq.ft., the extra weight may over-span them.
    Air seal the attic now, optimum time- as you will benefit greatly;http://www.google.com/url?sa=t&sour...sg=AFQjCNHwd56o0AxLi8-V03E5cMUmwWATQw&cad=rja

    Verify the attic ventilation requirements for your location, add more if needed (moisture on framing/exterior ice dams).

    Gary
     
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  9. Apr 15, 2013 #9

    drewdin

    drewdin

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    @GBR, awesome tips! Thanks!
     
  10. Apr 16, 2013 #10

    drewdin

    drewdin

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    So the Air handler is installed, I have an easy wiring question. The installer told me I needed a disconnect and an outlet per code. Is there a special disconnect I need to mount?I saw there was a 1/2" Knockout that was access to two hot terminals and a ground but no neutral. Does that sound correct? I know I am not in the right section of the forum, i can ask in the electrical section. Thanks
     
  11. Apr 16, 2013 #11

    kok328

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    Unfortunately, installers are not electricians and will not assume liability for installing the disconnect.
    Nothing special about a disconnect, don't let the terminology scare you. This is also known as a "service switch". It is just a light switch to cut power to the air handler for when repairs/maintenance is needed. If you interupt the two hot terminals with a switch, it will kill power but, the absence of a neutral makes me think that this is not the circuit that is powering the air handler. As far as needing an outlet, I don't know why they are requiring one but, it will require a neutral.
     
  12. Apr 16, 2013 #12

    CallMeVilla

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  13. Apr 17, 2013 #13

    kok328

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  14. Apr 17, 2013 #14

    drewdin

    drewdin

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    Yes, the air handler is correct. they said it was a 220v AHU, i would need a double breaker and a double pole switch. I code Mass Code is that an outlet is required near the unit along with a switch for servicing. The outlet must be a separate line.

    I put in a yellow 12-2 romex as they said they only needed a 20amp line. Now I have a line from the panel to the AHU but its not hooked up.

    I'll have to buy a metal box to mount to the AHU with a switch for the power. they said since its 220 that theres no neutral. news to me
     
  15. Apr 17, 2013 #15

    CallMeVilla

    CallMeVilla

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    Your post confuses me now. I have never seen a 220 VAC run with #12 wire. What is the gauge of wire feeding into the disconnect? He told you the line is only 20A ?? Are you setting up what is commonly called an "appliance plug" (not with #12!)? You had better check the installation instructions before finalizing this.

    If you are doing an appliace plug, then the picture below would apply. A neutral would be used. But not with #12 wire.

    However, the lack of neutral IS how it is done in AC applications where 220 VAC is required. ONLY IF your setup (per instructions) does NOT require a neutral would the following apply.

    The bare copper wire is the ground wire which needs to be connected to the green wire in the disconnect. This may be a lug or screw connection depending on the manufacturer. In either case the ground wire is connected in your service panel to the ground buss.

    The other two wires supply the 220 VAC. If you use either 10/2 or 8/2 cable you will have a white, black and copper wire in the cable sheath. The white wire should be taped with black tape to designate it as a HOT wire. (This tape flag is done at the main service panel and the disconnect to ensure proper identification) It is NOT a neutral. It will be connected to one of the power lugs in the disconnect. The remaining BLACK wire will be connected to the other power lug.

    220 VAC DIAG.jpg
     
  16. Apr 18, 2013 #16

    kok328

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    If you need 220V, I assume this is an electric heater, not gas.
    With this new information, I think they want a disconnect without the plug and the AHU would be hardwired to the disconnect.
    This setup would not requre a neutral.
    They are also asking for a 120V outlet to be used as a "service" outlet.
    The amp ratings for AHU will determine the AWG of wire to run (most likely not 12/2). Can you provide the amp rating for the AHU?
    12/2 is correct for a 20A service outlet.
     

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