Calculating Generator Size

Discussion in 'General Discussions' started by FYN409, Mar 6, 2011.

  1. FYN409

    FYN409 New Member

    We are getting ready to install a Carrier (Climatmaster) heat pump. We loose power often during the winter so we need a generator to run the system in the event we loose power. I am trying to determine the minimum size generator to run the system (without causing damage). We are looking at putting in a 3 ton unit. According to the specs the LRA is 82. Based on my calculations that comes out to just over 17kw's. Do you size to 100% LRA? This seem excessive as I currently am able to run my 3 ton A/C on a 5500 watt gen. It grunts a bit at startup, but seems to run it just fine.

    Any help you can offer would be appreciated.

  2. FYN409

    FYN409 New Member

    Smart Start

    Another option that my installer has mentioned is that Carrier has something called Smart Start that is supposed to help those that operate on a generator. But we are unable to find specs on what the LRA is when using Smart Start. Does anyone have any experience with smart start?

    From my calculations with without smart start I need a 17kw generator, seems extreme for a 3 ton system. I have seen several online posts stating that a 7.5 kw generator will handle a 3 ton, but they make no mention of LRA.

  3. Masoud

    Masoud New Member

    My 3 ton Climatemaster Tranq 27 works fine on a 15 K Generac propane generator.

    Emerson's Securestart (which I do not have) will lower the start up current.


  4. Masoud

    Masoud New Member

    This link may help: SecureStart

    Waterfurnace's Intellistart is a similar device to Securestart.

    Climatemaster, Bryant, and Carrier all have Securestart's installation manual available for download at their websites.
  5. geome

    geome Member Forum Leader

Share This Page