Marathon Heavy Duty

Marathon® Heavy Duty non-metallic electric water heaters are designed for harsh environments and a warranty to back it up

Non-metallic Tank Features

  • Seamless, blow-molded, polybutene tank – impervious to rust and corrosion
  • Multiple layers of filament wound fiberglass give the tank unmatched strength
  • Polyurethane insulation helps reduce energy consumption
  • Recessed drain valve is out of the way of brooms and scrubbers
  • High temperature polysulfone dip tube
  • Tough molded polyethylene outer shell resists dents, scratches, and salt air


  • Well insulated for reduced standby heat loss
  • Pipe wrap energy saving kit included to achieve maximum energy savings


  • Recovery Capacity: 18.2 gallons per hour (delivers approximately 78 gallons of hot water in the first hour for 75-gallon models, 91 gallons for 85-gallon models and 104 gallons for 105-gallon models)**
  • Thermostat capable of delivering water temperature up to 180° F for high temperature applications

Easy Installation & Service

  • Marathon’s lightweight tank is easier to maneuver and position
  • Bowl shaped tank bottom allows complete sediment draining
  • Water tight grommets keep out overhead moisture and condensation


  • Thermally fused upper element provides protection against dry firing
  • Titanium upper and lower elements for superior resistance to lime build-up
  • Full-flow, brass drain valve
  • Temperature and pressure relief valve and factory installed vacuum relief valve
  • Low lead compliant
  • Standard replacement parts

75  MHD75245
85 MHD85238
105 MHD105238

  • Available in 75, 85 and 105 gallon capacities
  • Seamless, blow-molded, polybutene tank - impervious to rust and corrosion
  • The most durable electric water heater ever made
  • High efficiency design and a lightweight tank that won’t corrode


Marathon Heavy Duty
Specification Sheet (US and Canada)
Use and Care Manual (Us and Canada)
Warranty Information


See Warranty Certificate for complete information

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