Troubleshooting Kohler 12RES Problem
I have a Kohler 12RES generator with an RDT 100 Amp Auto Transfer Switch.
Last week I noticed that my generator did not kick on for the weekly exercise test and that the red Source Available Light on the ATS was flashing rapidly. I tried starting the generator from the front control panel and the engine would not crank. When I put the generator on Run, all I heard was a rapid clicking noise and then nothing. No faults were displayed on the generator control panel. It did display a CC1 which indicates crank cycle 1 was attempted.
After troubleshooting per the manual, I discovered that the battery was dead Â a 2 year old DieHard Group 26 which I thought was odd. I took the battery to Sears and they tested it Â found it was bad. Bought a replacement, installed it, and was able to start the generator from the front panel. I cleared the fault on the Automatic transfer Switch per the manual and tried to run the generator remotely from the ATS panel using both the Exercise and Test buttons. In both cases, the generator started, ran for a little over a minute, and then shut down. When the generator stopped, I heard that rapid clicking noise again and then nothing. I looked at the front panel on the generator and noticed that it received a Stop command from the ATS. Generator Source red LED flashes rapidly after each start and then shut down. I repeated this process 3 times and same result each time.
The flashing red LED indicates one of two faults: Failure to Acquire Standby Source, and Failure to Transfer. Since both tests I ran were with no load transfer, I believe the first fault listed is the one. This fault occurs if the transfer switch does not sense voltage from the generator set within 78 seconds after signaling the generator to start.
I checked the output voltage on the generator terminal block and found that one side is putting out between 125 to 126 volts, while the other side is only putting out about 26 to 29 volts. It appears that the ATS is sensing that the wrong output voltage is being produced by the unit and automatically stopping the generator Â as it is supposed to.
I attempted to adjust the output voltage by programming the controller and could increase and lower the side outputting normally from 125 up to 138, and then back to 125 volts. But the other side did not change Â remained at a constant 29 volts during this test.
Does anyone have any idea which components on the generator could be causing this problem and how I can safely isolate which component is bad? It seems like it could be a bad voltage regulator and if so, I wonder if that component be replaced without replacing the entire controller? I am hoping this isn't something horribly wrong with the unit.