Generator won't start 3 ton condenser


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Old 09-06-19, 04:53 PM
J
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Generator won't start 3 ton condenser

I just had an 11KW Generac home generator installed. My 3ton Ruud 2011 condenser will not start. It pulls 112 on start up and Generac dealer says I need to get it down around 40 or 50 for it to be able to kick on with my "under powered" generator. He said to have HVAC people install a hard start kit. I've messaged Ruud to see if there is a recommended type or brand that would work with my model but have not heard back. I'm new to this world but trying to learn as much as I can before I have HVAC people out. Thank you
 
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Old 09-06-19, 05:12 PM
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Welcome to the forums.

Feet wise...... how many feet of wire are between the generator and the condenser ?
Just an educated guess..... doesn't need to be exact.

The more wire between the two the higher the starting load due to voltage drop.

Your hvac tech should have hardstarts on board his truck but there is no guarantee that will allow it to start. It's going to have to be tried.
 
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Old 09-07-19, 06:12 AM
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Hi, what are the specs on the condenser? Post a pic of the name plate.
Geo
 
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Old 09-07-19, 06:25 AM
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A hard start kit would reduce the starting current if your unit does not have one but it won't reduce it to less than half of what it is now.
But, as said you have nothing to loose by trying it.

Curious to know how you came to get a generator that was too small?
 
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Old 09-07-19, 05:01 PM
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Is anything else in the house using power when running your AC?

I suppose you'd need a 18-20kw generator to have the reserve capacity to easily take the 100(?) amp surge during starting. A 16kw generator might do it but if spending that amount of money I'd upsize to a 18 or 20 to make sure and allow me to have other things in the home running when the AC turns on.
 
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Old 09-09-19, 06:43 AM
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Thank you all for your responses. The AC unit is about 8 ft from the generator and right next to the transfer switch. Buying the 10 kw generator was my call based on our budget. I did all the plumbing and pad myself. Just hired an electrician for the transfer switch and to hook up to the unit. I was not sure if the AC would work, just hoping. What are your thoughts on the Emerson Secure Start Module. This looks like it would keep the starting amps way under the generator's threshold. There were no other electronics or compressors running at the tile I tested the AC while under generator power. I had a local Generac distributor come out to inspect the install and he said right away that the 10kw would not start it but recommended a soft or start kit. I'll try posting a pic of the AC specs.
Thank you again.
 
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Old 09-09-19, 06:47 AM
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pic of ac unit specs

Here are the specs for the RUUD AC unit.
Thank you
 
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Old 09-10-19, 09:40 AM
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11k generator should start a 3ton. We install the 11k all the time. Run AC or everything else. Works well. burns a lot less fuel doing this.
 
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Old 09-16-19, 03:18 PM
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Last update-
Thank you all again for your expert advice and opinions. I bought and installed a Sure Start (soft start) module https://www.gen-pro.biz/. It dropped the LRA from 112 to around 20 and the compressor and fan will now start while under 10kw generator power. The device was $250. There is another one out there for $450 Emerson Secure Start but I opted for the less expensive route since I was not sure it would work to begin with. And the lights in the house have stopped dimming when the air kicks on as well.
John
 
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Old 09-16-19, 04:40 PM
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So what was included in the soft start kit? I assume there is a capacitor but is there a simple relay or some more fancy electronic controls involved?
 
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Old 09-23-19, 07:35 AM
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I can not answer that. Sorry. I'm too much of a novice to even know what was in that device. Check out the Gen-Pro link from my previous post. That will give you all the info on the Sure Start Module. When the HVAC tech installed it he had to first remove the existing start capacitor and little control box. I don't think it involved a new capacitor. I think it just regulates and slows the incoming flow so the compressor starts slowly rather than with a quick kick? But like I said, I really have little understanding of the entire process. I know it is working though and the lights in the house are happy about it.
 
 

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