The Kohler 400RZXD is a 304-kilowatt LPG industrial standby generator in an open-frame (skid-mounted) configuration. Rated at 240-304 kW standby depending on voltage, it uses a PSI/Doosan engine paired with a brushless permanent-magnet pilot exciter alternator at 1800 RPM. The open-frame design is intended for indoor mechanical rooms or buildings with dedicated generator enclosures.
At this capacity, 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. At this power level, propane consumption is significant, so tank sizing and delivery contracts become critical planning considerations for extended outage scenarios.
OnPoint Generators provides installation, maintenance, and emergency service for Kohler gaseous generators throughout Northern California. The PSI/Doosan engine platform in the RZX series handles the 300+ kW class reliably, and we structure PM programs around annual ignition, fuel system, and coolant inspections.
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.
Manufacturer-recommended intervals for the Kohler 400RZXD 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 400RZXD?
The 400RZXD is rated 240-304 kW standby (300-380 kVA) depending on voltage configuration, with a prime rating of 272 kW (340 kVA), operating on LPG at 60 Hz.
What fuel does the Kohler 400RZXD use?
The 400RZXD operates on LPG (propane). Natural gas and dual-fuel variants are also available in the RZX 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.
400 kW gaseous-fueled commercial standby generator. Kohler/Rehlko 400REZXB — the flagship of Kohler's industrial gaseous lineup for large facilities and paralleling arrays. Note: the 400 kW Kohler gas genset is sold as the 400REZXB, not as 'KG400'.
