M500 Day Tank, Standard (50-1000 GAL)

Generator Day Tanks

The M500 is a traditional day tank, which is adaptable to meet a broad range of specifications. The day tank has onboard controls, sensors, and transfer pumps to reliably refill from remote bulk storage tanks.  The tanks are available as UL142 Double Wall or UL2085 Fire-Rated.  Day Tank Controls interface with generator systems with High, Low, Leak Contacts or optional Modbus / BACnet connectivity.

Mission Critical versions of the day tank are available with dual controls, sensors, and valves.

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  • Approvals: UL 142 or UL2085 Fire Rated
  • Capacity: 50-1000 GAL (200 - 4000L)
  • Power 120-230 VAC, 1 Phase, 50-60 Hz
  • Controller: UL 508, PLC Basis with HMI
  • Interface: Output Relays for High, Low, Leak and Modbus (Optional BACnet)


  • Inlet Solenoid Valves with Strainer and Ball Valve
  • 4 or 5 Point Level Sensor and Leak Sensor
  • Optional Level and Temperature Transmitters
  • Standard and Emergency Vents
  • Direct Read Level Gauge
  • Inspection Port and Cap Engine Supply and Return Connections
  • Return Flow Pump for Overfill Protection

Safe Fuel Storage Inside Buildings:

Earthsafe day tanks safely store fuel for generator engine consumption within the building. Day tanks are designed with integral secondary containment. Fuel transfer equipment and controls are designed for safe and reliable re-filling.   

Reliable Refill Systems: 

Day Tanks are designed and furnished with pre-assembled and tested fuel transfer equipment and controls. Inlet control valves, transfer pumps, level sensors, leak sensors, and other equipment are all monitored and controlled by the Earthsafe C1 or C8 control panels.

Integrated Building Management Systems:

Earthsafe advanced controllers allow for the communication of vital day tank operating information to other building systems. These systems may include Building Automation Systems, generator controls, switchgear and other power controls, security and fire alarm systems.

Readily Adaptable for Special Operation: 

Earthsafe day tanks can be readily adapated for special operation characteristics such as: dual inlet valves, monitored valve positions, high level / overflow pumping, emergency evacuation, auto-commissioning, fluid metering, high temperature control.