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GENERATORCODES

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RS home standby display

78

Low fuel pressure

Fuel · Shutdown

Fault code 78. The RS20 manual lists wire connections, the fuel system, and the fuel-pressure switch. The steps it prints are to open any closed fuel valves, then have a Cummins Onan dealer service the set.

Seen on: Cummins RS-series home standby sets covered by the RS20 operator manual. QuietConnect RS13A–RS20AC operator manual A053X174 repeats these fault code numbers.

Likely causes

  • A closed fuel valve.
  • Actual low fuel pressure or a fuel-pressure switch problem.

Checks an owner can do

  1. Open closed manual fuel valves. Do not disassemble the fuel regulator or propane piping.

When to call a pro

Fuel-pressure testing is dealer work. Gas leaks are an emergency: leave the area and call the gas supplier or fire department if you smell gas.

Source

Cummins RS20 home standby operator manual, section 5 (fault codes and blink pattern). The same code numbers are listed in operator manual A053X174 for the RS13A, RS17A, RS20A, and RS20AC QuietConnect sets.

Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.

What fixed mine

No approved reports for this code yet. Send one. It stays in the review queue until it is approved.

Related Cummins codes

https://generatorcodes.com/brand/cummins/78