RS Series 20AC

RS Series 20AC Natural Gas & Propane Residential Generators (Cold Weather Configuration

  • Equipped with cold weather climate kit
  • Very quiet operation
  • Internet remote monitoring and email notification
  • Automatic load management – The intelligent generator control automatically manages nonessential household loads for maximum utilization of generator power
  • Cummins Onan designed alternator and electronic control
  • Powerful motor starting – starts and runs a 5 ton A/C1 under full pre-load
  • 120 volt GFCI “Ready”
  • Self-diagnostic capability
  • Service and maintenance information displayed on in home display
  • Easy installation with innovative molded polymer installation base – no need for a concrete pad
  • Electronic governor for precise frequency control
  • Flexible 12 inch fuel line provided with genset
  • Generator designed and manufactured in the USA
  • U.S. EPA and CARB Emissions Certified
  • CSA Certified generator and transfer switch for your protection
  • Quality power output, less than 5% THD
  • 5 year, 2000 hour limited warranty
  • Click here to view our internet remote monitoring and email notification simulator


  • Integrated oil drain valve and extension tube included
  • Simple fuel conversion between natural gas and LP
  • 20 A battery charger
  • Highly reliable solenoid shift starter
  • Transistorized magneto ignition
  • Automotive-style lubrication system
  • Oil cooler
  • Spin-on oil filter
  • Electronic governor
  • Large-capacity air cleaner
  • CARB Certified, U.S. EPA Certified

Control System:

  • Cummins Proprietary electronic control with self diagnostics and generator set protection and safety features included
  • Automatically identifies power outage and starts generator
  • Microprocessor control manages generator set operation, fault detection and service diagnostics
  • Illuminated run/off/auto switch
  • Convenient access to all connection points
  • Fully automatic operation

Exhaust muffler:

  • Large automotive grade corrosion resistant muffler design
  • Low noise

Weight, Size & Sound Levels

Weight: 540 lb (245 kg)
Size: Length 53 in (1346 mm), width 43 in (1092 mm), height 34.7 in (880 mm)
Sound: 62 dB(A) at 23ft (7 m), at normal load2

Model Ratings

Series Order Model Part Number Fuel Voltage Frequency Rated amps3 Circuit Breaker Cold weather equipped Listing
RS20AC 20GSBB-6717A A030S533 Natural Gas 120/240 60 Hz 140/70 100 A, 2 pole Yes CSA, EPA
RS20AC 20GSBB-6717A A030S533 LP vapor 120/240 60 Hz 154/77 100 A, 2 pole Yes CSA, EPA

pdf image Specification sheet   pdf image Operator manual


Cummins Onan RS20A, RS 20AC, and 14AF generators come standard with a 5 year/2000 hour limited warranty. Extended warranty options available. See warranty statement for additional details.

Prices and Availability Subject to Change Without Notice

RS Series 20AC
Product Options
120KW Natural Gas (Air Cooled w/t cold weather kit)$4,780.00
220KW Liquid Propane (Air Cooled w/t cold weather kit$4,780.00
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