Kohler · REZX Series (Industrial Gaseous)

Kohler 500REZXD

500 kW standby · LPG · Liquid-cooled

500 kW LPG industrial standby generator. Enclosed gaseous standby with PSI/Doosan engine and pilot-excited permanent-magnet alternator.

Kohler Kohler 500REZXD generator — specifications and details
Standby power
500 kW
Voltage options
120/208V, 277/480V
Frequency / Phase
60 Hz · 3-phase
Engine
PSI/Doosan D219L · 21.9L
Alternator
Kohler Brushless, Permanent-Magnet Pilot Exciter

Overview#

The Kohler 500REZXD is a 500-kilowatt LPG industrial standby generator in an enclosed configuration. Rated at 362-500 kW standby depending on voltage, it uses a PSI/Doosan engine paired with a brushless permanent-magnet pilot exciter alternator at 1800 RPM. This is the largest unit in the REZX gaseous lineup, EPA certified for stationary emergency applications, with hurricane-rated enclosure options featuring 186 mph wind load rating.

Gaseous vs diesel at 500 kW#

At 500 kW, gaseous generators are at the upper end of what LPG can practically deliver in a single genset. The advantage over diesel remains: no on-site fuel storage, no SPCC compliance, and no fuel degradation concerns. However, propane consumption at this power level is very high, requiring substantial tank installations and reliable delivery infrastructure. For facilities on utility natural gas with a reliable pipeline, NG variants offer unlimited runtime without delivery logistics.

Our service experience#

OnPoint Generators provides installation, maintenance, and emergency service for Kohler gaseous generators throughout Northern California. The 500 kW class represents the top of the gaseous lineup and requires specialized attention to fuel delivery components, gas pressure regulation, and the pilot exciter alternator during PM service. We structure comprehensive service programs for these large-format units.

Engineering specifications

Physical

Length
161.4 in
Width
86.2 in
Height
97 in
Wet weight
11,820 lb

Fuel system & runtime

NG required pressure
7 in WC

Photos

Kohler 500REZXD — product photo

Documents & downloads

Spec sheets & manuals

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Service intervals

Manufacturer-recommended intervals for the Kohler 500REZXD 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.

ComponentSymptomTypical hoursSeverity
Spark plugs / ignitionMisfire under load, cylinder dropout codes, rough idle500+minor
Turbocharger sealsOil in intake, blue smoke, boost pressure loss10,000+moderate
Fuel pressure regulator / vaporizerHard starting, gas pressure fault, erratic idle8,000+moderate
Battery (starting)Slow crank, failed exercise8,760+minor

Frequently Asked Questions

What is the standby rating of the Kohler 500REZXD?
The 500REZXD is rated 362-500 kW standby (362-625 kVA) depending on voltage configuration, operating on LPG at 60 Hz.
What fuel does the Kohler 500REZXD use?
The 500REZXD 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

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.

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