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RS home standby display

79

Failure to transfer to the generator

Transfer switch · Shutdown

Fault code 79, failure to transfer to the generator set. The RS20 manual lists wire connections, a faulty position switch, and faulty transfer-switch components. Its steps are to verify the generator main AC breaker is On, then have a 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

  • Generator line breaker left off, so the transfer switch never sees generator power.
  • Position switch or another transfer-switch part.
  • Control wiring between the set and the switch.

Checks an owner can do

  1. If you can see the generator's own breaker and it is off, switch it on only when the set is not being serviced and you understand which breaker it is.
  2. Do not open the transfer switch cover.

When to call a pro

Transfer-switch mechanisms and position switches are electrician or Cummins dealer work.

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.

https://generatorcodes.com/brand/cummins/79