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I plan to buy aircon but have a question.

My friend office has 2 aircons. Both 220 volts.

3 toner 34000 BTU cooling capacity with 16.4 A rated current. Stand unit model Carrier CP-A280MA.

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I cant read korean but the specs is elsewhere like this

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Second aircon below is 1.5 toner 14000 BTU cooling capacity with 16.6 A rated current. Ceiling casette model Daikin RZR50LVVM. Is it 3 phase or can be installed as single phase? Technician still hasnt finished the installation because missing some controller.

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How can the one with twice cooling capacity has less current requirements. Any ideas? Note the 10000w is the cooling capacity, not the power input. 10000w is equal to about 34000 BTU.

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  • You would have to send pictures of the specification plates for these two units for the experts here to compare them. Oct 23 '20 at 22:47
  • The areas are different, so you are not comparing the same thing. Rate the specific prrformance per metre squared...
    – Solar Mike
    Oct 24 '20 at 4:40
  • What areas? I was just asking the equipment specs..why is the 34000 BTU only requiring 16.4A while the 17000 BTU is more at 16.6A. This is independent of actual areas where they are installed.
    – Jtl
    Oct 24 '20 at 4:48
  • Holy smoke, why does a 14,000 BTU unit need that much power? Oct 24 '20 at 14:30
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The current rating has to refer to the peak demand, most likely the startup current. The 14000 BTU unit might start the fan and compressor at the same time while the 34000 BTU unit manages the startup current to something reasonable, like a soft-start. When it comes to the average power consumption the 34000 BTU unit has to consume more. Maybe the average current of the 14000 BTU is like 5A and the 34000 BTU is 9A (those are guesses).

For the wiring you really need to look at the installation instructions. I will say that it looks like the RZR50LVVM would be a single phase in a country such as the UK where you get 230V on one phase. If you used the same thing in the USA, they use a split-phase, where a regular house only has 1 phase coming in but it's split and has opposing voltage, so 1 to neutral is 110V but 1 to the other is 220V and some people will call this 2 phases, so in the USA you would have to use 2 of those because for 60Hz (USA) it says 220-230V, but for 50Hz (ex. UK) it says 220-240V so that is like their regular mains voltage from 1 phase to neutral.

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  • I think rated current doesn't include the startup current.. does it? I think you have to multiply the rated current by 1.5 to get the startup current. Is this not what is done?
    – Jtl
    Oct 24 '20 at 13:17
  • Rated current generally doesn't include motor starting current, no... Oct 24 '20 at 15:04
  • Ok that's my bad then. Not sure why they only specify a 20A breaker for 16.6A unit if that doesn't account for startup current.
    – pgibbons
    Oct 25 '20 at 0:51

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