traverse517
When the utility power comes back online, there is no interruption in the power to the house. Not even a few cycles lost. The only way to know that the power has been restored is when you hear the generac shutdown.  Not sure why it's so seemless when the power comes back? I would think at least the digital clocks would sense the disruption when transfering back to utility power.

Thanks.
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murphy
Digital clocks and all electronic devices have electrolytic capacitors in their power supply that prevents them from "seeing" when there is no AC power applied during the milliseconds it takes for the switch to occur.  There are definitely more than a few cycles lost. My A/C compressor sometimes reverses direction during the switch if it was running.
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78buckshot
traverse517, what you are seeing is completely normal operation, and what murphy describes for his A/C is also common.
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Brian Baughman
HVAC equipment should always be connected to the load management control boards in the ATS, as this will prevent the equipment from running in reverse upon transfer back to utility.  This is why the board goes through the management cycle when the ATS transfer to utility power, it shuts down running HVAC equipment. Another solution would be the installation and use of the Hyper Engineering soft starter, as the soft starter will also prevent the HVAC equipment from running in reverse.
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Ron Goldstein Rongold
The SACM in my RXSW200A3 transfer switch opens up the A/C control lines upon transfer from utility to generator, but I don't think it opens the circuits upon transfer back to utility. I think it's only a one way deal.
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grsthegreat
Ya, i dont recall seeing the 4 green lights switch off on transfer back.
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BillM
That's been my experience.  The OPCB module (load mangement in the ATS) does not appear to notice or be aware of the transfer back to utility.  Also, I strongly urge everyone to TEST their unit.
I'm already on my second one.  If it fails like mine, you won't have any idea it failed.  Mine failed in what I will call the closed relay position.  So, when my utility failed and the generator started, I immediately had all green lights.  Also, the test button on the bottom that many forget about (you can't see it an it's not well labeled) had no effect.  So, for those of you that test your generator under a load condition, it is worth while to physically watch to see that the OPCB operates correctly.  I wish they had status lights on the outside of the ATS to make this safer and easier.  I wonder how many have failed like mine did and no one knows.
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