What is the standby rating of the Kohler KD1250-4?

Per the Kohler spec sheet, the KD1250-4 is rated at 1250 kW / 1562 kVA standby and 1130 kW / 1412 kVA prime continuous at 0.8 power factor, 60 Hz, 1800 RPM.

Is the Kohler KD1250-4 EPA Tier 4 certified?

Yes. The KD1250-4 is EPA Tier 4 Final certified with dual certification for both stationary emergency and stationary non-emergency applications, making it suitable for prime power duty where air quality regulations require Tier 4 compliance.

What alternator type does the KD1250-4 use?

The KD1250-4 uses a brushless, permanent-magnet pilot exciter alternator — Kohler's standard for the KD Series large industrial diesel platform.

Kohler · KD Series (Industrial Diesel)

Kohler KD1250-4

1250 kW standby / 1130 kW prime · Diesel · Liquid-cooled

1250 kW EPA Tier 4 Final diesel industrial standby generator. Dual-certified (emergency and non-emergency) for mission-critical and prime power applications.

Standby power: 1250 kW / 1130 kW prime
Voltage options: 277/480V
Frequency / Phase: 60 Hz · 3-phase
Engine: Kohler KD36V16 · 36L
EPA / Emissions: Tier 4 Final
Alternator: Kohler KH05520TO4D

Data Centers Healthcare Manufacturing Commercial Government

Overview#

The Kohler KD1250-4 is a 1250-kilowatt EPA Tier 4 Final diesel industrial generator from Kohler's KD Series platform. The -4 designation indicates Tier 4 Final emissions compliance with dual certification for both emergency standby and non-emergency (prime power) applications. This makes the KD1250-4 suitable for installations where air quality district rules require Tier 4 compliance or where continuous/prime duty is needed. The KD Series uses Kohler-designed engines and permanent-magnet pilot exciter alternators.

KD Series platform#

The KD Series is Kohler's large industrial diesel generator line, covering 800 to 4000 kW. Designed for mission-critical facilities, every KD Series unit carries UL 2200 listing and meets NFPA 110 Level 1 requirements when equipped with the necessary accessories. Hurricane-rated enclosures with 186 mph wind load ratings are available across the platform.

Our service experience#

OnPoint Generators provides installation, maintenance, and emergency service for Kohler KD Series generators throughout Northern California. Tier 4 Final units require additional aftertreatment system maintenance, including DEF management and DPF regeneration monitoring, which our technicians handle as part of comprehensive PM programs.

Engineering specifications

Acoustic

Sound @ 7m, full load: 97 dBA
Enclosure: Open

Fuel system & runtime

Fuel use @ full load: 88.2 GPH
Fuel use @ 75% load: 65.2 GPH
Fuel use @ 50% load: 44.1 GPH

Photos

Documents & downloads

Spec sheets & manuals

Spec sheet (datasheet)

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Fuel tank capacity

gal

Load

Override full-load GPH (optional)

GPH

Estimated runtime

2.9 hours(0.1 days)

Fuel consumption ≈ 68.04 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Kohler KD1250-4 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter: Every 500 hours or 12 months
Coolant change: Every 6000 hours
Air filter: Every 1000 hours
Fuel filter: Every 500 hours
Major overhaul: ≈ 20,000 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
DPF (Diesel Particulate Filter)	Regen warning, back-pressure fault, power derate	4,380+	moderate
DEF system (SCR catalyst)	Derate warning, NOx fault, DEF quality alert	4,380+	moderate
Fuel quality / degradation	Injector fouling, hard starting, black smoke under load	4,380+	moderate
Turbocharger	Power loss, excessive exhaust smoke, oil at turbo seals	15,000+	moderate
Cooling system (hoses / thermostat)	Overtemperature fault, coolant loss, high EGT	10,000+	moderate
Battery (starting)	Slow crank, failed exercise, low voltage alarm	8,760+	minor

Frequently Asked Questions

What is the standby rating of the Kohler KD1250-4?: Per the Kohler spec sheet, the KD1250-4 is rated at 1250 kW / 1562 kVA standby and 1130 kW / 1412 kVA prime continuous at 0.8 power factor, 60 Hz, 1800 RPM.
Is the Kohler KD1250-4 EPA Tier 4 certified?: Yes. The KD1250-4 is EPA Tier 4 Final certified with dual certification for both stationary emergency and stationary non-emergency applications, making it suitable for prime power duty where air quality regulations require Tier 4 compliance.
What alternator type does the KD1250-4 use?: The KD1250-4 uses a brushless, permanent-magnet pilot exciter alternator — Kohler's standard for the KD Series large industrial diesel platform.

Compatible equipment

Transfer switches

More in the KD Series (Industrial Diesel)

Kohler-engineered megawatt-class diesel gensets from 900 to 4000 kW for mission-critical facilities.

View all 18models in this series →

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