Using a Kohler RDT ATS to control a Kohler RCA Communicating Gen.

Kohler Home Standby & Commercial generator troubleshooting and repair questions
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Sammtillman
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Posts: 139
Joined: Tue Sep 15, 2020 8:42 am

The other day I was asked to hook up a Kohler generator set. The customer had bought a non communicating transfer switch RDT model. The gen. was a RCA model which uses a communicating RDC2 controller. I rarely install Kohler so I had to bring the manuals home to study. I was unsure if the equipment would match up. Both Generac and Briggs don’t have communicating systems so I had very little experience with The Kohler communicating units. Of course communicating systems are easy to wire. There will be a A.B. Terminals for the computer signals and the two terminals for power on side. Generators use 12vdc , HVAC equipment uses 24vac power. After taking a closer look at the equipment I started realizing that Kohler controls the signals through there ATS. This includes the exercising functions as well. It has a cute little LED panel on the front of the ATS which indicates which sources are available. A engine start signal output comes off a 6 pin green connector. Terminals 3 and 4 send a 12 volt signal to the generator start . The RCA Gen. Sets are communicating but can be used with no n. communicating systems. TB2. On the generator has a 6 screw connection. Terminals 3 and 4 are used for the engine start. Terminals 1and 2 are the A.B. And 5 and 6 are control power. These terminals will not be used. The generator has a separate utility circuit for the battery charger. I used a 4 conductor to hook up the generator. A breaker in the ATS was not provided for the utility circuit so I wired in a 5 amp inline fuse through the circuit. The manual recommends using shielded cable for communicating systems and separate cables.
This might be a good read for any of you techs that are asked to hook up a Kohler for the first time!
nrp3
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Joined: Sat Nov 10, 2018 9:56 am
Location: NH

RDT will work with a lot of stuff, now that two wire start controllers are becoming more common. Just did two Kohler replacements with Generac and used existing RDT switches. Added fuses for N1 and N2, strictly for oil warming. These were older RDT units and had a convenient circuit breaker to handle T1. Works fine.
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