Hot Transformer for Honeywell UV2400U5000 UV light

Discussion in 'HVAC Heating & Cooling' started by korr565, Apr 21, 2021.

  1. korr565

    korr565 New Member

    Joined:
    Apr 21, 2021
    Location:
    Florida
    Hello. I installed the Honeywell UV2400U5000 UV light in my air handler a few months back and noticed recently how hot the transformer is getting--too hot to touch for more than a 3-4 seconds. This seems unusual from what I've read. Should I be concerned?

    Since my air handler is variable speed, I took the advice I read many places and wired the UV light to a separate 24v 40VA transformer and separate constant external power. The light draws 16VA.

    Everything is located in my attic, which is easily accessible but hot and humid (Florida). Not sure if this is related in any way.

    Thank you for any feedback.

    Kevin
     
  2. korr565

    korr565 New Member

    Joined:
    Apr 21, 2021
    Location:
    Florida
    Followup...this morning I checked and the transformer was just warm, not hot. So, I'm guessing the problem IS related to the environment--the hot Florida attic during the day.

    I failed to mention previously that, in order to avoid further crowding in the air handler control box, I mounted this transformer outside the air handler altogether. Should I try to mount it inside?

    Many thanks again
    Kevin
     
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  4. fitter30

    fitter30 Well-Known Member

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    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    Honeywell transformers are rated to to 105*f since your attic will get hotter mount it in the air handler
     
  5. korr565

    korr565 New Member

    Joined:
    Apr 21, 2021
    Location:
    Florida
    Thanks, fitter30. Much appreciated. I should've thought of that--the air inside the handler will be cool!
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    It's going to make the AC less efficient. How about making that transformer easy to change, and leave it outside for now?

    https://www.winsupplyinc.com/emerson/_/A-07684507 is a transformer rated for 150F ambient. I would try for a higher-rated transformer, and leave it in the heat.
     
    Last edited: Apr 22, 2021
  7. korr565

    korr565 New Member

    Joined:
    Apr 21, 2021
    Location:
    Florida
    Thanks Reach4. Could you explain how it would affect efficiency? I'd still power it separately from the air handler, even if mounted inside. BTW, here are the specs on the transformer I have.

    Approvals: Class 2 UL5085-3 Approved, C-UL, CSA, RoHS
    130(B) insulation system
    Mounting: Foot mount or hub mount
    Over Current Protection: Inherently Limited
    Input: 120VAC, 60HZ
    Output: 24VAC/40VA
    Demension: See in pictures
    PRI.: UL 1015 18AWG Length 208mm in color "black","white"
    Operating Temperature: -40 to 140°F
    MTBF: 100,000 Hours @ 77°F
    Construction: Split-Bobbin
    Product Weight: 720g / 1.59lb
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    The transformer generates heat to the extent that it is not 100% efficient. If that heat is generated inside the air handler, that is more heat that your AC has to remove.

    I don't know how much heat is generated. Worth worrying about? I am not sure.
     
  9. SShaw

    SShaw Member

    Joined:
    Nov 17, 2019
    Location:
    Virginia
    In the winter that heat would increase the efficiency.

    If it were 95% efficient, the heat loss would be 0.05 x 40VA = 2 Watts. It's probably somewhere between 2-6 Watts, so not likely an efficiency driver.
     
  10. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    6 watts is 20.47 Btu/h. So maybe not worth considering.

    https://en.globtek.com/news/30va-lo...vel-v-efficiency-standard-model-gt-73107-3024 has some numbers. They are bragging about their efficiency.
     
  11. korr565

    korr565 New Member

    Joined:
    Apr 21, 2021
    Location:
    Florida
    Thanks, all. Very helpful. Since it's easy enough, I'm going to try it inside the handler for a day and closely monitor it.
     
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