Overview#
The Generac SG035 is a 35 kW standby natural gas and LP vapor generator set built on Generac's own 4.5-liter naturally aspirated inline-4 spark-ignited engine — designed and manufactured at Generac's Wisconsin facilities. Rated at 44 kVA standby and 39 kVA prime at 60 Hz, the SG035 is the entry point into Generac's industrial SG-Series gaseous lineup, covering commercial standby applications including small office buildings, light manufacturing facilities, and retail spaces.
Standard equipment includes the Power Zone Pro controller with NFPA 110 Level 1 compliance, a factory-installed radiator rated for 50°C (122°F) ambient operation, and dual primary/secondary fuel shutoffs. The SG035 carries UL 2200 and UL 6200 listings, CSA C22.2 certification, and EPA stationary emergency certification. Sound-attenuated Level 1 and Level 2 enclosures are available as factory options.
The 4.5L engine uses electronic fuel injection with a Generac-designed electronic governor providing ±0.25% steady-state frequency regulation. The Power Zone Pro controller supports Modbus RTU, Modbus TCP/IP, and Ethernet 10/100 communications, enabling integration with BMS and monitoring platforms without third-party adapters.
Technical Specifications#
Power Ratings (60 Hz, 1800 rpm)
| Rating | kW | kVA |
|---|---|---|
| Standby | 35 | 44 |
| Prime | 32 | 39 |
Engine — Generac 4.5L Inline-4 SI
| Parameter | Value |
|---|---|
| Displacement | 4.5 L (275 in³) |
| Configuration | Cast iron inline 4-cylinder |
| Aspiration | Naturally aspirated |
| Compression ratio | 9.94:1 |
| Rated speed | 1,800 rpm |
| Emissions | EPA Certified Stationary Emergency |
| Oil capacity | 21 qt (20 L) |
| Fuel type | Natural gas, propane vapor |
| Fuel inlet pressure (NG) | 5–14 in WC (1.2–3.5 kPa) |
| Fuel inlet pressure (LP) | 7–14 in WC (1.7–3.5 kPa) |
Fuel Consumption — Natural Gas (standby rating)
| Load | Consumption |
|---|---|
| 25% | 184 scfh |
| 50% | 273 scfh |
| 75% | 361 scfh |
| 100% | 446 scfh |
Physical (Open Set)
| Dimension | Value |
|---|---|
| Length | 78.1 in (1,981 mm) |
| Width | 37.3 in (946 mm) |
| Height | 44.4 in (1,128 mm) |
| Dry weight | 1,675–1,748 lbs (760–793 kg) |
Level 1 acoustic enclosure: 94.8 × 38.0 × 57.5 in, steel 2,258–2,329 lbs.
Control System — Power Zone Pro
Power Zone Pro provides NFPA 110 Level 1 compliance, digital voltage regulation (±0.25% steady state), electronic governor control, and a 4.3-inch color touch screen display. Communications include Modbus RTU, Modbus TCP/IP, and Ethernet 10/100, with SNMP support and remote software update capability. Alarm and event logging with real-time stamping is standard.
Our Service Experience#
The SG035 is one of the more straightforward units in the commercial gaseous range — the 4.5L inline-4 is compact and the Power Zone Pro controller simplifies diagnostics with its built-in event log and programmable I/O. Spark plug condition is the most common service item on naturally aspirated SI engines in this size class; we recommend inspection at 500 hours and replacement at 1,000 hours regardless of appearance. Fuel pressure at the inlet is worth checking at every annual service — the 5–14 in WC required range is narrow enough that low-pressure utility supply or undersized gas lines cause hunting and governor hunting symptoms that are easy to misdiagnose as a control problem.
Frequently Asked Questions#
What fuel types does the SG035 support? The SG035 runs on natural gas or propane vapor. Natural gas requires 5–14 in WC supply pressure; propane vapor requires 7–14 in WC. The unit is not rated for liquid propane injection.
What voltages are available on the SG035? The SG035 alternator supports 120/240V single-phase at 1.0 pf, and three-phase configurations at 120/208V, 120/240V, 277/480V, and 346/600V, all at 0.8 pf.
What controller does the SG035 use? Standard is Power Zone Pro, which includes Modbus RTU and TCP/IP communications, a color touch screen, NFPA 110 Level 1 compliance, and programmable I/O. This is a significant capability upgrade over the older Digital H control used on some earlier SG models.
What enclosure options are available? Open set, weather-protected enclosure, Level 1 acoustic, and Level 2 acoustic. Level 1 and Level 2 enclosures are available in steel or aluminum. Enclosures are rated for up to 200 mph wind loads by factory special order.
What is the warranty on the SG035? Standard is 2-year limited warranty for standby-rated units. Extended warranties of 2, 5, 7, and 10 years are available through Generac Industrial Power dealers.
