The Hipower HNG-355 is a 354 kW stationary natural gas standby generator in Hipower's HNG series. At 354 kW, this unit serves large commercial buildings, industrial facilities, and healthcare campuses where diesel storage at this scale would require a large tank installation with SPCC compliance. Natural gas supply from the utility eliminates that infrastructure — at the cost of requiring a high-capacity gas service and careful gas system engineering.
CARB certification enables California permit-by-rule for the HNG-355. In the 300–400 kW range, CARB-certified natural gas stationary options from non-Big-4 manufacturers are limited, making the HNG-355 a notable specification for California project teams.
Gas supply engineering is critical at this output level. A licensed mechanical engineer must size the complete gas system — utility meter capacity, regulator, and distribution piping — for the full-load BTU demand. Early utility coordination is recommended.
The HNG-355 is powered by a PSI natural gas engine running at 1800 RPM. PSI supplies spark-ignited engines to multiple standby generator manufacturers and maintains a broad parts and service network across North America. The specific PSI model designation for this output range is pending verification from OEM documentation — service follows standard PSI spark-ignited practice: spark plugs and oil at 1000-hour intervals, no DPF or DEF.
Hipower's HNG series holds CARB certification for California natural gas stationary standby. The HNG-355 qualifies for California permit-by-rule — standard air district approval without source test.
OnPoint Generators services large natural gas standby generators throughout Northern California. The HNG-355 is appropriate for industrial and large commercial facilities where the decision to build on natural gas standby is driven by compliance simplification and fuel infrastructure efficiency.
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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
3,717,000 BTU/hr≈ 3717.0 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 Hipower HNG-355 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.
Oil & filter
Every 1000 hours or 12 months
Air filter
Every 500 hours
Spark plugs
Every 1000 hours
Major overhaul
≈ 30,000 hours
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
Erosion from natural gas combustion — replace at 1000-hour intervals
1,000+
minor
Gas pressure regulator
Pressure drop under full load — verify regulator capacity matches full-load BTU demand
4,380+
minor
Ignition module
Cylinder misfire under load — diagnose per-cylinder ignition output
8,000+
moderate
Frequently Asked Questions
What engine does the HNG-355 use?
The HNG-355 uses a PSI natural gas engine. PSI is Hipower's engine supplier for the HNG stationary series above 100 kW. The specific PSI model designation for this output range is pending verification from OEM documentation.
Is the HNG-355 CARB certified?
Yes. Hipower's HNG natural gas series holds CARB certification for California stationary standby applications.
What applications is the HNG-355 suited for?
Large commercial buildings, manufacturing facilities, hospitals, and data centers where 354 kW of natural gas standby eliminates diesel storage and SPCC compliance requirements at this scale.
What gas supply infrastructure is needed at 354 kW?
354 kW natural gas demand requires a well-engineered gas service — meter capacity, regulator sizing, and piping must be designed for the BTU demand at full load. Engage a licensed mechanical engineer and coordinate with the utility early in the project. <!-- NEEDS VERIFICATION: HNG-355 BTU/hr and gas pressure requirements -->
Is the HNG-355 available with 600V output?
Yes. The HNG-355 supports 347/600V alongside 120/208V and 277/480V.
Who services HNG units in Northern California?
OnPoint Generators provides service for Hipower HNG series generators throughout Northern California.
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