Cummins/Onan — Over / Under Voltage Module Recalibration
Adjustments · Over / Under Voltage Module (A17)
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DGBB, Cummins/Onan DGBC, Cummins/Onan DGCA, Cummins/Onan DGCB, Cummins/Onan DGDA, Cummins/Onan DGDB, Cummins/Onan DGEA, Cummins/Onan DGFA, Cummins/Onan DGFB, Cummins/Onan 4B3.9 engine
Procedure
- Remove the two screws securing the top to the case and withdraw the top assembly.
- Adjust the UNDER setpoint SET pot to 75 percent.
- Apply single-phase, 60 Hertz, 104.25 VAC across terminals L and N.
- Adjust pot R25 on the PC board until the relay trips (de-energizes).
- Adjust the OVER setpoint SET pot to 125 percent.
- Apply single-phase, 60 Hertz, 173.75 VAC across terminals L and N.
- Adjust pot R26 on the PC board until the relay trips (energizes).
- Repeat until no adjustments are necessary, then reassemble the module.
Specs & values
- Typically 10 percent over and under nominal voltage
- Mark out factory calibration value (120 V) and write in 139 V on the nameplate
Full service-parts list: Cummins/Onan DGBB →, Cummins/Onan DGBC →, Cummins/Onan DGCA →, Cummins/Onan DGCB →, Cummins/Onan DGDA →, Cummins/Onan DGDB →, Cummins/Onan DGEA →, Cummins/Onan DGFA →, Cummins/Onan DGFB →
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.