Generac · MG Series (Modular Gaseous)

Generac MG250

250 kW standby / 225 kW prime · Natural Gas / LPG · Liquid-cooled

250 kW modular natural gas standby generator system. Factory-paralleled for N+1 redundancy.

Standby power
250 kW / 225 kW prime
Voltage options
120/208V, 277/480V, 346/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Generac 14.2L Inline-6 SI · 14.2L
Alternator
Generac K0250124Y21
CommercialManufacturingHealthcareData CentersGovernment
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Overview#

The Generac MG250 is a 250 kW modular natural gas generator rated at 250 kW / 313 kVA standby (225 kW / 281 kVA prime) at 60 Hz. It uses a Generac turbocharged 14.2L inline-6 spark-ignited engine and is built on the Modular Power System (MPS) platform with a Power Zone Pro Sync controller for factory-integrated paralleling capability. This is a popular choice for healthcare and campus applications where both reliability and natural gas convenience are priorities. The MPS architecture enables N+1 redundancy configurations.

Our Service Experience#

The MG250 uses the Generac 14.2L inline-6 turbocharged engine at 250 kW (190 psi BMEP per the spec sheet), which is near the top of this platform's output range. Exhaust temperatures reach 1,357 F at rated output. Turbocharger condition monitoring is important at this loading level. The Power Zone Pro Sync controller manages paralleling when multiple MG units are deployed. With 6 spark plugs per unit, ignition maintenance is straightforward. Gas supply sizing must account for the 3,180 CFH demand at full load.

Engineering specifications

Physical

Length
136 in
Width
57.1 in
Height
67.9 in
Dry weight
5,883 lb

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Generac MG250

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

2,625,000 BTU/hr≈ 2625.0 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 Generac MG250 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Air filter
Every 1000 hours
Spark plugs
Every 2000 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 plugsMisfiring, rough running, reduced power output2,000+minor
Gas regulator / fuel trainUnstable speed, hard starting, fuel pressure faults15,000+moderate
Paralleling controller synchronizationFailed sync, load sharing imbalance, hunting20,000+moderate
BatteryFailed to start, slow cranking8,760+minor

Frequently Asked Questions

What is the difference between the MG250 and the SG250?
The MG250 is a 250 kW gaseous generator built on Generac's Modular Power System (MPS) platform using a turbocharged 14.2L inline-6 engine with factory-integrated paralleling capability. The SG250 uses the same 14.2L engine platform but is configured as a standalone unit. The MG250's MPS architecture enables N+1 redundancy configurations and the ability to service one unit while others continue operating.
What fuel types does the MG250 support?
The MG250 supports both natural gas and liquid propane (LP/LPG). Natural gas is the most common fuel choice as it eliminates fuel storage requirements and provides unlimited runtime with utility gas service.
What voltages are available?
The MG250 supports three-phase configurations: 120/208V, 277/480V, and 346/600V at 60 Hz.

Compatible equipment

Transfer switches

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