Bosch Therm 520 HN NG Indoor Natural Gas Tankless Water Heater

At 117,000 BTU/hr maximum input, the Bosch Therm 520 HN NG produces enough power for running a shower and a sink simultaneoulsy.

  • 78%+ thermal efficiency
  • Patented Hydro-power ignition requires no electricity
  • Vents with galvanized B vent, natural draft
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SKU: B-520-HN-NG-ITWH Category:

Water Heater Description

The Therm 520 HN NG incorporates an evolutionary hydro-power ignition system which allows this tankless water heater to work without a standing pilot, grid connection or battery. A small turbine inside the water heater uses the energy from the flowing water to ignite the burner. Makes this an ideal product for installations without access to electricity or regions prone to inclement weather and power outages. Utlizes natural gas as a fuel.

Manufacturer SKU: Bosch Therm 520 HN NG

Manufacturer PDF: Bosch_Therm_Compact_Tankless_Water_Heaters_Sell_Sheet.pdf

Water Heater Specifications




Natural Gas


Tankless (whole house)

Ignition Type


Energy Star


Water Heater Warranty

Waterheaters.com will honor all warranties in accordance with manufacturer policies and procedures. Manufacturer warranty issues should be addresses directly with the manufacturer.

15 year limited warranty on heat exchanger | 2 year warranty on all other parts