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AquaStar Gas and Propane Tankless Water Heaters

This page introduces the AquaStar Gas and Propane Tankless Water Heaters range and links to the model sheets held for it.

AquaStar Tankless Water Heaters

by Bosch and fueled by Propane (LP) and Natural Gas

AquaStar's line of Tankless Water Heaters are available in both Propane Gas (LP) and Natural gas. There are 3 sizes that can be used in single or multiple unit installations to deliver continuous hot water in residential and commercial applications.

Enough hot water for 2 showers at one time!

Battery Sparked Ignition - no outside power required

Electronic Ignition with a built in power vent

Standing pilot used for Solar applications

High usage in conjunction with a holding tank

Small usage for sinks and other low flow needs

Model 240FX

(Formally known as the T-K1) This large Gas or Propane Water Heater will produce enough hot water for 2 showers running at the same time! The AquaStar 240FX is very efficient and has a built in power vent.

  • Technical Information about the 240FX
  • Applications - and Versatility of the 240FX
  • 240FX Vs Tanks - 240FX wins!
  • Accessories for the 240FX
  • 240FX Warranty

Model 125X

Developed by Bosch engineers, the 125X introduces the first battery sparked ignition tankless water heater to the U.S. market. Because the heater uses no energy when idle, the 125X has an energy factor of .80 - the average storage tank heater has an energy factor of just .59. The frame, heat exchanger, burners, and gas valve are the same as the reliable 125B.

  • Technical Information about the 125X
  • Applications
  • Power Venting
  • 125X Warranty

Model 125FX

The New! the 125FX is the same great water heater as the 125X - but with a built in power vent.

  • Technical Information about the 125FX
  • Applications
  • 125FX Warranty

Model 125B

The 125B is the right size model for most homes and is the ideal household water heater. It offers the same high performance of the 125X, but has a standing pilot.

  • Technical Information about the 125B
  • Applications
  • Power Venting
  • 125B Warranty

Model 125BL

This model is designed for recirculating to a storage system, for commercial water heating, and for hydronic and radiant space heating up to 150° F.

  • Technical Information about the 125BL
  • 125BL Indirect Application
  • Power Venting
  • 125BL Warranty

Model 125BS

Specifically designed as a backup to preheated water such as that produced by solar or wood heating systems. The burners turn off when the preheated water is already at the desired temperature. Is perfectly suited for solar applications.

  • Technical Information about the 125BS
  • 125 BS Solar Application
  • Power Venting
  • 125BS Warranty

Model 38B

This very small tankless water heater is ideal for cottages, camps, and other applications such as farms and ranches. The 38B can also be used in smaller heating (baseboard and radiant) and recirculating applications up to 30,000 BTUs. Not used for running showers.

  • Technical Information about the 38B
  • Power Venting
  • 38B Warranty

Design Features & Specs AquaStar FAQ's U.S. Department of Energy's Report on Tankless Water Heaters Great News for Oregon Residents!

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