Generac 20kw will not transfer back to line power!

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tomcatgen
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Wed Aug 07, 2019 9:48 pm

Model number is 20KW/999 GUARD+ 200A SE A, SERIAL IS 6716951 - The power went out due to lightening hitting a high voltage transformer. The Gen took over automatically and is still running, but the line power has been restored! First thing I tried was to cut the system off and then reset the line/standby switch. I could not get it to reset so So pushed the trip button and then got it to reset after some time. I then set the Gen back to auto and the Gen displayed something like ,"no line voltage starting 10 second countdown". After the countdown the Gen started and the line/standby switch went back to standby. We do have power but it is from the Gen and not from the line power. I read through the "not resetting threads" and did not find anything just like our situation. I did a continuity check of the 3 fuses taken from the ATS and they seem intact. I took off the 23 wire? from the ATS and the system did not revert to line power. I checked the voltage bet. 23 and 193 (I think) with Gen off and it was 11.3vdc. - it was 0vdc when Gen was cut back on (may have this reversed, can't remember which way it was. I have looked at the DIAGnostics and they did not help. I do not know where to go from here - I have not looked at voltages on the ATS relay or limit switch & not certain how to get to them. I have not checked the electronics in the Gen yet, suppose I would have to take the numerous screws off to get to the wiring harness & relay there as well. Any hints would be grand, as I have only done PM on this unit over the last 7 3/4 years. ATS BOX had not been opened since the contractor installed it in Dec 2011 until today!
Chris
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Thu Aug 08, 2019 4:57 pm

If the generator is giving you a countdown delay, that means that it thinks you still do not have power. You can shut the generator off and if you have utility power available the transfer switch should automatically switch back to the utility side. If those fuses are showing good, the lightning strike may have fried the controller in the generator. :sad:
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