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  • Bosch Tankless Water Heater (Pro Series) - Liquid Propane - 520 HN LP

    - 117000 btu

    Product ID • 520HNLP00000

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The Bosch Propane Tankless Water Heater Therm 520 HN LP incorporates an evolutionary hydro-power ignition system which allows this Bosch tankless water heater to work without a standing pilot, grid connection or battery! A small turbine inside the propane water heater uses the energy from the flowing water to ignite the burner.

The modulating gas valve then maintains a constant temperature at varying flow rates. This innovative technology, patented by Bosch, makes this an ideal product for installations without access to electricity or regions prone to inclement weather and power outages.

This Bosch Therm 520 HN Propane Tankless Water Heaters must be installed by Professional Installers.


This item does not qualify under California's Title 24 Guidelines, therefore it cannot be installed in California.

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Technical Specs

Bosch Pro Tankless Water Heater 520 HN Techs and Specs

  • Type
  • Fuel Type
    Propane Gas (LP)
  • Application
  • Max Input (BTU)
  • Min Input (BTU)
  • Capacity at 35 (°F) Rise (gpm)
  • Capacity at 55(°F) Rise (gpm)
  • Intelligent Cascading
  • Min Flow Rate
    0.6 gpm
  • Temp Range (°F) High
  • Thermal Efficiency
  • Installation Options
  • Width
    18 ½ inches
  • Height
    36 ¾ inches
  • Depth
    10 ½ inches
  • Weight (lbs.)
  • Inlet Connection
    ½ inch NPT
  • Outlet Connection
    ½ inch NPT
  • Gas Connection
    ¾ inch NPT
  • Max Water Pressure
    150 psi
  • Min Water Pressure
    30 psi
  • Venting Options
    Galvanized B-Vent
  • Energy Star Rated

Bosch Pro Tankless Water Heater 520 HN Features

  • Patented Hydro-power ignition requires no electricity
  • 80%+ thermal efficiency
  • 117,000 BTU maximum input
  • 5.3 gallons per minute capacity at 35F degree rise
  • Endless hot water for 1 application at a time
  • Minimum activation flow rate of 0.6 gallons per minute
  • High to low temperature control
  • Vents with galvanized B vent – natural draft
  • Built for durability and serviceability with 15-year warranty and 20+ year life expectancy

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