Kohler — Source Voltage and Frequency Check Procedure
Testing & diagnosis · Transfer switch sources (Normal and Emergency)
From a Kohler service manual — check it applies to your exact model before use.
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Before you start
- Hazardous voltage. Only authorized personnel should open the enclosure.
- Do not connect or disconnect the controller harness when the power is connected.
Procedure
- Press OFF on the generator set controller and verify the generator set is off.
- Disconnect both power sources from the transfer switch.
- Disconnect the contactor wiring harness from P13 (single-phase) or P1 (3-phase) on the interface board.
- Manually operate the transfer switch to position E.
- Close the utility source circuit breaker; check utility voltage across NL1-NL2 and each to neutral.
- For three-phase, repeat voltage checks across NL1-NL3 and NL3-NL1.
- Disconnect Source N; manually operate to position N; press RUN to start the generator set.
- Check generator voltage and frequency at EL1 and EL2 and each to neutral.
- For three-phase, repeat checks across EL2-EL3 and EL3-EL1.
- If voltage/frequency do not match the nameplate, adjust the generator set.
- Stop the generator set; disconnect both sources; reconnect the harness to P13 or P1.
- Close and lock the enclosure door; reconnect both power sources; press AUTO.
Tools required
- Digital voltmeter (DVM) with insulated probes Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.