The Kohler 300REZXC is a 300-kilowatt natural gas industrial standby generator in an enclosed configuration. Rated at 230-300 kW standby depending on voltage, it uses a Doosan engine paired with a brushless permanent-magnet alternator at 1800 RPM. This unit is EPA certified for stationary emergency applications and features hurricane-rated enclosure options with a 181 mph wind load rating.
At 300 kW, natural gas generators offer a compelling alternative to diesel: no on-site fuel storage, no SPCC compliance, no fuel degradation, and effectively unlimited runtime on utility gas. The primary risk is that natural gas supply depends on the utility pipeline remaining operational during the outage event. For facilities where the gas utility is historically reliable, natural gas standby is an excellent choice at this power level.
OnPoint Generators provides installation, maintenance, and emergency service for Kohler gaseous generators throughout Northern California. Natural gas units in the 300 kW class require attention to gas pressure regulation and fuel train components in addition to standard ignition and coolant service. We structure PM programs accordingly.
Tell us about the application — kW, voltage, application, install timeline — and we'll respond within one business day with budgetary pricing, lead time, and any sizing notes.
Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.
Estimate runtime on this tank
Fuel demand at 75% load
3,150,000 BTU/hr≈ 3150.0 cf/min @ 1,000 BTU/cf
On utility natural gas the runtime is generally unlimited provided the supply line and meter can deliver this BTU/hr at the engine's required inlet pressure (typically 5–14" WC residential, up to 5 psi commercial). Confirm against the OEM's published fuel-pressure spec.
Service intervals
Manufacturer-recommended intervals for the Kohler 300REZXC under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.
Oil & filter
Every 250 hours or 12 months
Coolant change
Every 3000 hours
Air filter
Every 500 hours
Spark plugs
Every 500 hours
Major overhaul
≈ 8,000 hours
Load bank test
Every 12 months
Common failure modes
What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.
Component
Symptom
Typical hours
Severity
Spark plugs / ignition
Misfire under load, cylinder dropout codes, rough idle
500+
minor
Turbocharger seals
Oil in intake, blue smoke, boost pressure loss
10,000+
moderate
Fuel pressure regulator / vaporizer
Hard starting, gas pressure fault, erratic idle
8,000+
moderate
Battery (starting)
Slow crank, failed exercise
8,760+
minor
Frequently Asked Questions
What is the standby rating of the Kohler 300REZXC?
The 300REZXC is rated 230-300 kW standby (230-325 kVA) depending on voltage configuration, operating on natural gas at 60 Hz.
What fuel does the Kohler 300REZXC use?
The 300REZXC operates on natural gas. It is purpose-built for pipeline natural gas applications, offering unlimited runtime as long as the gas utility remains operational.
What is the difference between RZX and REZX models?
RZX designates the open-frame (skid-mounted) configuration, while REZX is the enclosed (sound-attenuated or weather-protective) version. Both use the same engine-alternator package; the difference is the enclosure.
300 kW gaseous-fueled commercial standby generator. Kohler/Rehlko 300REZXC large industrial gaseous unit for major facilities, paralleling applications, and campus power. Note: the 300 kW Kohler gas genset is sold as the 300REZXC, not as 'KG300'.
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100 kW gaseous-fueled commercial standby generator. Upper-mid-range industrial gaseous unit for larger commercial facilities on natural gas or propane.
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