What is the standby rating of the Kohler 250REZXB?

The 250REZXB is rated 170-260 kW standby (213-325 kVA) depending on voltage configuration, with prime ratings of 225-235 kW, operating on LPG at 60 Hz.

What fuel does the Kohler 250REZXB use?

The 250REZXB operates on LPG (propane). Natural gas and dual-fuel variants are also available in the REZX line.

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.

Kohler · REZX Series (Industrial Gaseous)

Kohler 250REZXB

260 kW standby / 235 kW prime · LPG · Liquid-cooled

260 kW LPG industrial standby generator. Enclosed gaseous standby with Doosan engine for large commercial and institutional applications.

Standby power: 260 kW / 235 kW prime
Voltage options: 120/208V, 277/480V
Frequency / Phase: 60 Hz · 3-phase
Engine: Doosan D146L · 14.6L
Alternator: Kohler Brushless, Permanent-Magnet

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Overview#

The Kohler 250REZXB is a 260-kilowatt LPG industrial standby generator in an enclosed configuration. Rated at 170-260 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 both stationary emergency and non-emergency applications, with hurricane-rated enclosure options available featuring 186 mph wind load rating.

Gaseous vs diesel at 260 kW#

At 260 kW, gaseous generators eliminate on-site fuel storage requirements and SPCC compliance. LPG provides clean combustion with lower emissions than diesel and avoids fuel degradation issues common with low-runtime standby diesel. At this power level, propane consumption is significant, so tank sizing and delivery contracts become important planning considerations for extended outage scenarios.

Our service experience#

OnPoint Generators provides installation, maintenance, and emergency service for Kohler gaseous generators throughout Northern California. The Doosan engine platform in the REZX series handles the 200+ kW class reliably, and we structure PM programs around annual ignition, fuel system, and coolant inspections with attention to the higher-capacity fuel delivery components.

Engineering specifications

Physical

Length: 137.8 in
Width: 68.9 in
Height: 84.6 in
Wet weight: 7,055 lb

Fuel system & runtime

NG required pressure: 7 in WC

Photos

Documents & downloads

Spec sheets & manuals

Spec sheet (datasheet)

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Service intervals

Manufacturer-recommended intervals for the Kohler 250REZXB 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 250REZXB?: The 250REZXB is rated 170-260 kW standby (213-325 kVA) depending on voltage configuration, with prime ratings of 225-235 kW, operating on LPG at 60 Hz.
What fuel does the Kohler 250REZXB use?: The 250REZXB operates on LPG (propane). Natural gas and dual-fuel variants are also available in the REZX line.
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.

Compatible equipment

Engine

Doosan D146LEngines

Transfer switches

More in the REZX Series (Industrial Gaseous)

Kohler REZX enclosed gaseous gensets from 190 to 500 kW — LPG, natural gas, or dual-fuel with Doosan power.

View all 12 models in this series →

Why we recommend Kohler

Kohler is our primary recommendation for commercial standby power. We sell and service the full Kohler line — RCA residential, RCL light commercial, KG industrial diesel, and REOZ large-frame — and our technicians are factory-trained on every product family.

We are an authorized Kohler dealer with factory-trained technicians. Kohler is the majority of our new generator sales today, spanning residential through large industrial. Our parts inventory is stocked for same-day Kohler service.

See all Kohler generators →

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Last reviewed: May 5, 2026