Cummins/Onan — Isolating the Transfer Switch for Service
Operation · Transfer switch / bypass switch
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- High voltage components within the cabinet present a serious electrical shock hazard.
Procedure
- Turn the Source Select switch to the source that will be connected to the load. If bypassing to the opposite source, power will be momentarily interrupted.
- While holding the Source Select switch, move the bypass switch handle to the source to be connected to the load.
- Release the Source Select switch; the load is now bypassed and the automatic transfer switch may be isolated for service.
- Turn the key operated Drawout Release switch and turn the drawout crank handle counterclockwise to the limit of its rotation.
- Release the Drawout Release switch; the lower cabinet door may be opened to service the transfer switch.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.