Cummins/Onan LS-15M — Rupture Basin Leak Detect Switch Test
Testing & diagnosis
For the Cummins/Onan LS-15M, from the Cummins/Onan service manual.
Applies to: Cummins/Onan DFAA, Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCB, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan DFE
Procedure
- Remove the pipe fitting/switch assembly from the rupture basin tank.
- Move the Run/Off/Auto switch to the RUN position.
- Activate leak detect switch (move float upward).
- Check control display for Rupture Basin fault message; if no indication, repair defective circuit.
- Apply thread sealant to pipe fitting and install switch assembly.
Tools required
- Thread sealant Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →, Cummins/Onan DFE →
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.