Kohler — Overvoltage Feature Testing and Adjustment (Decision-Maker 3+)
Adjustments · Controller main circuit board GM28725 overvoltage feature
From a Kohler service manual covering: 125REOZJG, 150 REOZJ4, 150REZG, 175REOZT4, 2000REOZM, 2000REOZMD, 2250REOZDD, 275REOZJD, 275REOZJE, 400REZX, 400RZX, 48REOZK4…. Check it applies to your exact model before use.
Applies to: Kohler 125REOZJG, Kohler 150 REOZJ4, Kohler 150REZG, Kohler 175REOZT4, Kohler 2000REOZM, Kohler 2000REOZMD, Kohler 2250REOZDD, Kohler 275REOZJD, Kohler 275REOZJE, Kohler 400REZX, Kohler 400RZX, Kohler 48REOZK4
Before you start
- Hazardous voltage. Moving parts. Will cause severe injury or death. Operate the generator set only when all guards and electrical enclosures are in place.
- Disconnecting the electrical load. Hazardous voltage will cause severe injury or death.
Procedure
- Disconnect generator set from load by opening line circuit breaker or disconnecting and taping output leads.
- Determine overvoltage shutdown value based on user requirement; factory setting is 15% above nominal line-to-neutral voltage.
- Remove the controller cover.
- Place master switch in RUN to start the generator set.
- Observe AC voltmeter; turn voltage adjustment potentiometer CW until generator set shuts down.
- If the shutdown point is correct, go to step 12; otherwise continue.
- Turn controller circuit board R42 adjustment potentiometer fully CW.
- Place master switch to OFF/RESET to reset; then to RUN to start.
- Observe AC voltmeter while turning voltage adjustment potentiometer to desired overvoltage shutdown point.
- Turn R42 adjustment potentiometer slowly CCW until the generator set shuts down.
- Turn controller voltage adjustment potentiometer slightly CCW.
- Place master switch OFF/RESET then RUN to start; adjust for correct voltage and phase.
- Place master switch OFF/RESET to stop.
- Disconnect battery negative lead first; reconnect generator set to load; reconnect battery negative lead last.
Specs & values
- Factory setting 15% above nominal voltage
- Maximum value about 200 volts
Full service-parts list: Kohler 125REOZJG →, Kohler 150 REOZJ4 →, Kohler 175REOZT4 →, Kohler 2000REOZM →, Kohler 2000REOZMD →, Kohler 2250REOZDD →, Kohler 275REOZJD →, Kohler 275REOZJE →, Kohler 48REOZK4 →
Source: Kohler service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.