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Thread: Real-world inrush current for Trane XV19 Heat Pump

  1. #1
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    Real-world inrush current for Trane XV19 Heat Pump

    Hello,

    I'm a homeowner looking to purchase a Trane XV19 heat pump. We already have a backup generator and I would like to be able to run the heat pump during a power outage. The generator can produce a maximum peak current of 50A for 2 secs at 240V. The datasheet for the XV19 (3 ton, model #4TWL9036A) lists an LRA of 48.9. I don't think this is enough buffer as the generator will be supporting some other small loads in an outage. Has anyone measured the real-world peak inrush current for an XV19 heat pump? I'm hoping it's less than the published spec pf 48.9.

    Thanks,
    Josh

  2. #2
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    Won't matter if its 2 amps less. Your genny is too small. Since the condenser fan and indoor unit's fan will also be starting.
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    Quote Originally Posted by beenthere View Post
    Won't matter if its 2 amps less. Your genny is too small. Since the condenser fan and indoor unit's fan will also be starting.
    Exactly!

    Also LRA isn’t the same as inrush. Inrush can be higher. Current is limited a little more in a locked rotor situation due to heat build up. If I actually wanted to power my home and use the hvac system I wouldn’t go smaller than a 22kw generator.
    "I think Quantum tunneling would work great... "

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    Thanks for the replies. Unfortunately the generator is part of a solar/backup setup which is already installed, so I don't have any flexibility there. 50A peak at 240V is what I've got to work with...

    I also have a low noise requirements because the heat pump will be close to a property line, which is how I got to the XV19. Another option would be a compact Daikin heat pump. I can't find any LRA specs for those and I'm wondering if maybe that's because they are inverter driven and don't have any large inrush current like the Trane XV19?

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    Your not going to be able to start that 3-Ton unit on the generator! Small inverter units can BUT are much more sensitive to changes in voltage and Hz so will probably shut down on a safety and eventually lock out.

    I also have a low noise requirements because the heat pump will be close to a property line

    And your running a generator?

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    Call the installer and have them contact their FSR. They can get you "part load amperage" which is what you need. It is my understanding that LRA is only if the compressor would lock up and not turn. Start up on the VS compressor is often less than full load amps because they do not start and 100% they start slow and speed up.

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  10. #7
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    Quote Originally Posted by BNME8EZ View Post
    Call the installer and have them contact their FSR. They can get you "part load amperage" which is what you need. It is my understanding that LRA is only if the compressor would lock up and not turn. Start up on the VS compressor is often less than full load amps because they do not start and 100% they start slow and speed up.
    Actually in rush can be 2 - 3 times LRA for the 1st millisecond then drop to LRA then drop as the stator begins to turn. I had a peak amp meter once, is was interesting to see how high inrush can be.

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  12. #8
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    Technically it's a "solar generator" which is really a large Li backup battery and an inverter. Like a Powerwall, but made by Generac. So yes, totally silent.

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    Quote Originally Posted by pecmsg View Post
    Actually in rush can be 2 - 3 times LRA for the 1st millisecond then drop to LRA then drop as the stator begins to turn. I had a peak amp meter once, is was interesting to see how high inrush can be.
    At a training class I was at when Trane came out with their VS systems that was a selling point. The starting amps on a VS compressor was less than max normal running amps. Because of this it was a selling point for homeowners that wanted to be able to run their system on a generator. Since it did not draw as many amps on start up the owner did not need as big of generator as for a regular system.

    I agree that inrush on a standard compressor can be much higher than LRA but these systems don't start on high speed like a regular compressor. Or at least that is the way it was explained at that class.

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    Quote Originally Posted by jbl415 View Post
    Thanks for the replies. Unfortunately the generator is part of a solar/backup setup which is already installed, so I don't have any flexibility there. 50A peak at 240V is what I've got to work with...

    I also have a low noise requirements because the heat pump will be close to a property line, which is how I got to the XV19. Another option would be a compact Daikin heat pump. I can't find any LRA specs for those and I'm wondering if maybe that's because they are inverter driven and don't have any large inrush current like the Trane XV19?
    I’m actually working on a daikin right now with a dead compressor. I would not recommend them.
    "I think Quantum tunneling would work great... "

    "Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon."

  15. #11
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    Quote Originally Posted by JayMan7 View Post
    I’m actually working on a daikin right now with a dead compressor. I would not recommend them.
    So what killed the pump?

  16. #12
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    Quote Originally Posted by pecmsg View Post
    So what killed the pump?
    We’ll have to cut it open to find out for sure but the oil return cap tube is frequently a problem on these (it’s a very poor design). We also replaced the coil because it failed as well after only 5 years.
    "I think Quantum tunneling would work great... "

    "Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon."

  17. #13
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    Glad I bought a Fujitsu

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    I guess someone will need to enlighten me....

    Inrush amps on XV19 will be extremely low....Maybe 5-10 amps at most?

    That unit is variable capacity....The blower motor on the indoor unit will likely be too....

    Now the heat strips, that's a different ball game. Those you wouldn't be able to run....

    But if you had a dual fuel system with gas a furnace back up when temps went below 40* you should be able to do it....

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  20. #15
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    A variable speed compressor wont have a high in-rush current but does not play well with dirty power. I'd recommend something like the ICM 493 on the condenser and the furnace/AH. If your generator doesnt use an inverter to clean up the power, ask the sales rep what they use to accomplish this. You cant see the damage that's occurring to electronics but it's there

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    Quote Originally Posted by Makeitcold View Post
    A variable speed compressor wont have a high in-rush current but does not play well with dirty power. I'd recommend something like the ICM 493 on the condenser and the furnace/AH. If your generator doesnt use an inverter to clean up the power, ask the sales rep what they use to accomplish this. You cant see the damage that's occurring to electronics but it's there
    I like that state of Jefferson you got there....Caught my eye...

    Never been to Cottonwood but I've been to Willows for the ThunderHill race track many times.....Surprisingly it gets damn hot there. Especially in Racing leathers on the bike....

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    Quote Originally Posted by jacob-k View Post
    I like that state of Jefferson you got there....Caught my eye...

    Never been to Cottonwood but I've been to Willows for the ThunderHill race track many times.....Surprisingly it gets damn hot there. Especially in Racing leathers on the bike....
    What are you riding? What association? I did WERA/ CCS/ FUSA/ AMA for about 10 years, but retired in '07. Eastcoast here though. VIR, Road Atlanta, Summit Point, etc..
    "The only true wisdom is in knowing you know nothing" Socrates

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    Quote Originally Posted by mgenius33 View Post
    What are you riding? What association? I did WERA/ CCS/ FUSA/ AMA for about 10 years, but retired in '07. Eastcoast here though. VIR, Road Atlanta, Summit Point, etc..
    AFM is what we have here....

    2013 ZX10R and a 2017 ZX10RR.....

    I watch those tracks on YouTube, MotoAmerica.....

    Been about 2 years now since I've been, but I got my bikes and actually just started prepping for a track day a few weeks ago.....Damn race suit don't fit no more....they don't stretch much...lol

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    I moved up from the SF Bay Area 20 years ago, never knew it got that hot, that far north!

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