Cummins/Onan — Adjusting Voltage Using Control Switch
Adjustments · genset controller
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKB, Cummins/Onan MDKBH
Procedure
- Start the genset and let voltage and frequency stabilize for 5 to 10 seconds with all loads disconnected.
- Rapidly press START 6 times during the first minute after startup to enter voltage adjust mode.
- To adjust voltage up, press and quickly release START (about 0.6 volts per press).
- To adjust voltage down, press and hold START for about 2 seconds (about 0.6 volts each press).
- Wait about 20 seconds for the amber lamp to stop blinking, then press STOP to save the adjustment.
- Restart the genset and check voltage.
Tools required
- separate voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Voltage changes approximately 0.6 volts per press and release
Full service-parts list: Cummins/Onan MDKB →, Cummins/Onan MDKBH →
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.