Kohler automatic transfer switch RDT CFNA 0100B. I can set it to exercise and it will do so for several weeks then it forgets. No fault shown.

Are there any faults listed on the control display? If display is dark then likely a battery issue. Check battery voltage with a Digital Multi Meter (DMM). It should be at least 12.5VDC.

Disconnect the control wires and see if it still does it

The problem is not likely battery related. It sounds like either an ignition or fuel control relay that is not actuating due to missing electrical voltage.

Is there a fault?? All UL listed generators including Kohler are required to lockout on a fault on shut down. This really sounds like a problem with your 2-wire auto start connection between your automatic transfer switch and genset. RDT model automatic transfer switch it is the 2 middle wires on the green connector and terminals 3&4 in the generator. close to run and open to shut down. Any open at any time will cause the unit to shut down. The 12 will shut down instantly upon an open because your 5 minute cool down is built into the transfer switch.

I have a Kohler 12RESM1 whole-house generator with a 200AMP RDT, MPAC 500 Automatic transfer switch (ATS) in my home. The system was installed in 2006 and has been working great since. Several weeks ago I began noticing that the weekly tests weren't occurring on schedule and that the generator would initiate a starting crank for a couple seconds several time a day. The false starts began occurring more frequently as time progressed. (BE very careful!! You will be killed if you are not careful!! ) In order to isolate the trouble between the ATS and the generator, I disconnected the 2 start circuit wires from the ATS controller (2 wires on green connector). The problem stopped, which led me to believe the problem was the ATS controller board. The controller board in my ATS is a GM35950. After removing the board (BE very careful!! You will be killed if you are not careful!! ) and doing a little troubleshooting, I determined the trouble was the set of .47F 5V super-capacitors. These are the 2 black oval-shaped cans behind the relays that appear hot-glued together. I ordered 2 new caps from Digi-key (approx. $4.00 ea). The P/N is PB-5R0V474-R. Replacing the supercaps cured the problem. Don't be fooled, these capacitors are .47 farads, not .47 microfarads, thus the reason they're called Supercaps. They function similar to a battery in this application. Oh by the way, I ordered a couple extra Caps. They have a 1000 hour life expectancy, so I suspect I'll need to replace them again in 6-7 years. Good Luck, I wouldn't advise attempting this job unless you have the proper soldering equipment and are experienced with electronic repair. There's a company that will repair the board for $170. Try googling "Kohler GM35950 repair".

http://www.kohlerpower.com/onlinecatalog/salesservicelocator.htm

sounds like the voltage sensor is either mis adjusted or burnt up. Also could be a wire disconnected on the voltage sensor board.

The automatic test cycle is done for reasons besides just checking to see if it works, it is done to keep the engine in working order. Without running it regularly, it won't be able to run when you need it. If you really don't want the generator as a backup at all, you should sell it. On the other hand, maybe it's just noisy and runs at an inconvenient time. The electrician that installed it probably left a sticker for a number to call on the generator unit itself (or the transfer switch.) for service or questions. They should be happy to answer your questions about changing the schedule of the test cycle - and if they any sense at all for customer loyalty, they will probably do it for free.

The e-prom controls how the ATS behaves. It is very important to install the e-prom, so that the ATS works when power fails.

On your Automatic Transfer Switch ( the little gray box you see on the right in the picture above) you have two blue buttons. One is a Manual test switch. The other has a clock on it and this is your exercise set button. Hold it down for a FULL 3 seconds if you want it to excercise without a load (not powering your home) Hold it down for a FULL 6 seconds if you want it to exercise with a load every week. Your generator will start and run for 20 minutes, and then shut down. Now every week your generator will exercise at the time and day that you pushed the set button.