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  1. #1
    Join Date
    Feb 2008
    Location
    Cincinnati
    Posts
    12

    Curious about electrical requirements

    I work for an Amana distributor and the recent change in the AMVC95 unit requires 20 amp circuits for the 090 and 115 variable speed models with 5 ton drive. The previous AMV9 model only required 15. Although the communicating technology is welcomed, the higher amp requirement requires new wire changes, which is sometimes nearly impossible without great expense and time.

    I was just curious about other mfg and what amp requirements their V/S products with 5 ton drive have:

    Carrier
    Trane
    Lennox
    Nordyne
    York

    Any feedback is appreciated.

    Thanks.

  2. #2
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,517
    A 5 amp difference is so minimal. I would imagine in 99% of applications, the wire size isn't going to make a difference, and only if it is a long run from the breaker box to the furnace. Most electricians when a house is wired are going to plan on it being a 20amp circuit.
    I like DIY'ers. They pay better to fix.

  3. #3
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Ditto!!!


    Change the breaker and be done with it!!! I honestly think some of these electrical requirements are way out of hand.

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,721
    It will make a difference in some older homes. Where they only ran a 14 guage wire.
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  5. #5
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Quote Originally Posted by beenthere View Post
    It will make a difference in some older homes. Where they only ran a 14 guage wire.
    Hey Been, I will admit I'm not really familiar with those units. What amperage do these furnaces "actually" run at max?? My bet would be less than 8 or so, but that's just based off past experience.

  6. #6
    Join Date
    Jul 2008
    Location
    Poestenkill, NY
    Posts
    769
    Since when does running 12-2 require great expense and time?

  7. #7
    Join Date
    Nov 2008
    Posts
    1,673
    skinnier supply wires than recommended =
    higher source resistance =
    motor starting difficulties =
    shorter motor lifetime,
    but this may not be noticed by the HO.
    If it's a problem I guess you could put on a soft-start kit.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,721
    A 1 HP 120 volt blower can draw 8 plus amps itself.

    Most of the units I see, are rated for a 15 amp circuit. With the 5 ton drive units being list as a max circuit protection of 20 amps, which would require a 12 guage wire.
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  9. #9
    Join Date
    Jul 2008
    Location
    Poestenkill, NY
    Posts
    769
    Quote Originally Posted by beenthere View Post
    A 1 HP 120 volt blower can draw 8 plus amps itself.

    Most of the units I see, are rated for a 15 amp circuit. With the 5 ton drive units being list as a max circuit protection of 20 amps, which would require a 12 guage wire.
    MCOP (Maximum Circuit Overcurrent Protection) of 20 wouldn't require actually using a 20 A circuit.

    MCA (Minimum Circuit Ampacity) of 20 would.

    If neither of those ratings are given, FLA probably is (Full Load Amps), and if that exceeds 12, you need a 20 A circuit. (12 is max for a 15 A circuit)

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,721
    If you use a 20 amp beaker it does.



    If you use FLA/RLA to determine a circuit protection.
    You must multiply the highest drawing motor by 1.25(125% of RLA) and then add the amp draw of all other motors, and or current consuming devices in that appliance. To come up with the min circuit protection.
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  11. #11
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Good info guys, thanks......


    In a lot of the older homes here in the Seattle area, running a new circuit can be the difference between getting the job and not. I foresee some "hack" companies in this area not doing it and winning the job because of it. I just need to figure out how to enforce it. I mean, I can educate the customer but a lot of them, ahem, especially on the Eastside of this area only see dollars, they don't see sense(pun intended).

  12. #12
    Join Date
    Jul 2008
    Location
    Poestenkill, NY
    Posts
    769
    Quote Originally Posted by beenthere View Post
    If you use a 20 amp beaker it does.



    If you use FLA/RLA to determine a circuit protection.
    You must multiply the highest drawing motor by 1.25(125% of RLA) and then add the amp draw of all other motors, and or current consuming devices in that appliance. To come up with the min circuit protection.
    Absolutely, the wire definitely needs to match the breaker, no matter what.

    I could be wrong - but I think RLA would need the 1.25 multiplier, but FLA would not. In other words, I don't think FLA and RLA are synonymous. Do you know for sure?

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    Full Load Amp is the amp draw when a motor is running at its rated load, voltage and frequency.
    So is RLA.

    Its just a change in terminology, but means the same thing.
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