Cummins/Onan — Generator Set Will Not Stop When Load Is Removed
Testing & diagnosis · Stop Circuit
From a Cummins/Onan service manual covering: 15.0 HA, 15.0HA-23/24D, 15.0HA-23/25D, 7.5 HA, 7.5HA-21/24D, 7.5HA-21/25D, 7.5HA-23/24D, 7.5HA-23/25D. Check it applies to your exact model before use.
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Procedure
- Confirm that all loads are removed.
- Cranking limiter K3 normally-closed contacts are open. Depress reset pushbutton.
- Check for B+ voltage at stop relay K8 terminals 30, 87 and 85. If voltage is present at terminal 30, but not at 87, relay K8 is possibly defective. Check voltage at TB1-6. If voltage is absent, check
- Put Auto-Manual switch to Manual position and stop generator set by placing the unit switch to Stop position. Remedy as necessary by correcting wiring or replacing relay K8.
Source: Cummins/Onan 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.