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  1. #27
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    I have run the furnace before using the generator no problem, Its 3 yrs old.

    Again it doesnt seem like that ac will draw that much according to the people I talk to but maybe they dont know

    http://www.gillettegenerators.com/cgi-bin/sizing.cgi

  2. #28
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,085
    Quote Originally Posted by fixitguy View Post
    Most generators arent a nice sine wave..
    2T AC =24000 BTU divide by 3.4 equals 7058 watts.. the start surge may be
    THREE TIMES THAT for a 1/2 second..
    1.5T =18000 BTU = 5300 watts and the furnance fan hasnt started......
    Course the furnance has to be running for the blower fan, thats 10 amps maybe 14 amps by itself.. so now add 1200 watts for that...

    WHAT???

    7,058 watts would be an amp draw of 29.41 amps.

    What brand of of 2 ton A/C do you install that is that inefficient.


    2 ton A/Cs generally run at 14 to 18 amps(depending on load, age of A/C, SEER, etc).
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  3. #29
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    That link was figured using 5 100watt light bulbs, 1 refridge/freezer, furnace motor and 24,000 btu ac unit

  4. #30
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    I just re-read that, so you are saying the start sure can be 21,000 watts ????

  5. #31
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,432
    Quote Originally Posted by fixitguy View Post
    Most generators arent a nice sine wave..
    2T AC =24000 BTU divide by 3.4 equals 7058 watts.. the start surge may be
    THREE TIMES THAT for a 1/2 second..
    Thankfully thats not how A/C's work. An A/C will remove around 8-10 BTUs per watt, so a 2 ton unit should use around 2400-3500 watts including the condenser fan. However the compressor, especially if its a scroll will have a huge startup inrush current. You may find that you need to have a hard start kit installed. If you find that a hard start is necessary, request a 3-wire kit be installed


    Also when starting big loads on the generator, sometimes it helps to already have a small load like a 100 watt light bulb on. When I used to run my old belt drive furnace off my 3500 watt generator, the engine would stall when the motor tried to start if i didn't have a bulb on. After I switched out the furnace for one with a direct drive motor, I had no more problems like that.

  6. #32
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    Humm so...If I try it it will either work or not correct ?? It wont burn up the ac unit ?? Wouldnt my surge or 8550 be enough ??

    I see the fan motor on the outside unit where is the compressor ??

  7. #33
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,085
    Quote Originally Posted by cvcman View Post
    I see the fan motor on the outside unit where is the compressor ??
    Its in there somewhere.

    If its a Rhee/Rudd, the compressor is in a different compartment then what you see through the fan blades.
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  8. #34
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    Its a Carrier ac unit Rheem 95+ furnace

    Jim would it hurt to try the ac w/o anyhting else ?/ Also it should be safe to run the furnace with it right ??

  9. #35
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,085
    You have to run the furnace for the A/C to work.

    You should be fine to run a 1.5 to 2 ton A/C.

    Trying it once should do no harm to the A/C, or generator if it can't handle the load. Should stall out the gen if it can't handle the load.
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  10. #36
    Join Date
    Apr 2008
    Location
    Upstate New York
    Posts
    799
    ok so if I hear it load the gen for a sec then after starting it runs normal im ok right ? Just the blower in the furnace will be runnig right ?

  11. #37

    whatever happened

    Well, cvcman, what happened w/ your generator-ac?

    Anyone else, here's what I've got going. I'm attempting to power my 4 ton, 14 SEER unit with a 7550W continuous, 13500W start peak troy-bilt generator. It ain't working.

    First, I had to bypass the 30A circuit breaker on the generator because it kept tripping immediately. 13500W at 240V ought to be good for 56A, so I just connected the generator directly through the 40 fuse panel for the compressor. I'm only attempting to power the compressor, not the furnace/blower; I'm leaving the furnace on the grid for now.

    Apparently the compressor wants something over 60A for starting and maybe as high as 100A. I can't figure how people are being successful with 5kW units (I've been told by a master electrician that should be sufficient). Am I going to need a 24kW generator? Yikes. If that be the case, I'm dead in the water.

    The A/C guy told me to try a kicker capacitor but it turned out that the one he supplied me with was smaller than the run cap. When I looked at it, I thought it wouldn't work; I mean if the generator isn't putting out enough to start the compressor, then it isn't going to charge the cap and start the compressor. Well, that's the best he had for me and I thought I might as well try it, but of course it didn't work.

    Anybody have ideas?

    Thanks,

    ~Dan

  12. #38
    Join Date
    Apr 2006
    Location
    Chicagoland
    Posts
    690
    2 ton a/c
    Generator ran my a/c and blower.
    other generator ran fridge, tv, equipment.. what else does a man need, cold beer, some tv and a cool house lol
    I got the generator for free can`t beat that! only downfall was having to refuel every hour.


    Sorry - yesterday was the deadline for all complaints.

  13. #39
    That looks like a pretty small generator too. What size is it and how does this post help me??

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