AquaStar 125HX NG, 125HX LP Features, Unpacking the 125 HX Heater, Principle of Operation

Page 3

Principle of Operation:

When a hot water faucet is opened, the water flow through the heater causes the gas valve to open. At the same time the hydro-generator activates the electronics which sends a spark to the pilot. The flame sensor confirms the pilot has been lighted and allows the first two burners to come on. The flame sensor confirms correct activation and all burners come on. The pilot goes off. The heat exchanger coils absorb the heat generated by the burners and transfer heat to the water. When the hot water faucet is shut off, the gas valve automatically closes and the burners turn off. Your hot water faucet is an ignition key to activate the water heater, giving you control over your hot water energy use. Every time you turn off your hot water faucet, the energy consumption of your hot water returns to zero.

FEATURES

-Electronic Pilot Ignition driven by hydro-generator

-High Quality Materials for Long Working Life.

-Copper heating coils for endless supply of hot water.

-Burner output proportional to hot water flow demand for maximum energy efficiency.

-Safety flame sensor at pilot burner.

-Automatic overheating protection shut-off sensor.

-Flue gas safety device.

-Stainless steel burners with stabilized blue flame.

-Built-in corrosion resistant draft diverter.

-Compact space saver: mounts on a wall with two hooks.

-Easily removable one-piece cover.

-Easy one person installation.

-Adjustable water flow restrictor to ensure that water flow demand will not exceed the heating capacity of the heater.

-On/Off Switch to activate system.

-Red LED indicator flashes with low water pressure.

-Green LED indicator main burner operation.

BOSCH is constantly improving our products, therefore specifications are subject to change without prior notice.

125 HX LP and 125 HX NG Specifications

Gas Input max.: 117,000 Btu/hr min.: 28,000 Btu/hr

Water Connection ½” Thread fitting NPT

H x W x D 29 3/4” x 18 1/4” x 8 3/4"

Vent 5”

Gas Connection 1/2” NPT thread

Min. Water Pressure 18 Psi at 4 GPM

Max. Water Pressure 150 Psi

Shipping Weight 43 LB

Net Weight 40 LB

1.8GPM at 90° rise

3.7GPM at 45° rise

Min. Water Flow 1/2 gal/min

LP GAS Supply Pressure

(before 125 HX regulator) min. 11” W.C. max. 14” W.C.*

Required LP GAS Pressure at inlet

tap while 125 HX is operating: 10.5” W.C.

LP GAS Burner Manifold pressure while 125 HX is

operating at maximum input:

9.0” W.C.

Natural Gas Supply Pressure

min.: 7” W.C.

(before 125 HX regulator)

max.: 14” W.C.*

Required Natural Gas Pressure at inlet

tap while 125 HX is operating:

5.7” W.C.

Natural Gas Burner Manifold Pressure while 125 HX is

operating at maximum input:

4.2” W.C.

*Inlet gas pressure before 125 HX regulator must not exceed this value. Pressure may need to be adjusted for high altitudes, see page 9.

UNPACKING THE 125 HX HEATER

This heater is packed securely. The box includes one water connection fitting, a control knob with collar, a gas pressure regulator, a pressure relief valve, an incandescent particle tray, two hooks for hanging the heater, this manual and a warranty registration card. Do not lose this manual, as there is a charge for replacement. Please complete and return the enclosed warranty registration card.

6 720 606 804

3

Page 2 Page 4
Image 3
Page 2 Page 4
Contents For Your Safety Table of ContentsWhat to do if YOU Smell GAS 720 606 Required Natural Gas Pressure at inlet FeaturesUnpacking the 125 HX Heater Principle of OperationModel 125HX General Rules to Follow For Safe Operation Proper Location for Installing Your HeaterMounting Installation Combustion AIR RequirementsClearances Venting Plasterboard, can cause failure of mountingVent pipe connection Masonry Chimneys Existing Interior Masonry ChimneyTile Lined Interior Masonry Chimney GAS Connections GAS Line Sizing6 Adaptor Used on High Altitude For Natural GAS For LP GASSource National Fuel Gas Code Nfpa 54, Ansi Z223.1 Operating Instructions Water ConnectionsSetting the Water Temperature Lighting and Operating InstructionsTo Turn OFF GAS to Appliance Not enlarge the orifice Maintenance and ServiceTrouble Shooting Review Maintenance Table on the Back of this ManualNo Spark AT the Pilot Water is TOO HOT Ground water temperature is very warmPilot Lights but Burners will not Come on Main Burners GO OUT During HOT Water USEHOT Water Temperature Fluctuates / Unit Deactivated Diagram of 125 HX Interior Components Diagram and Parts List Interior Components Diagram Parts List 125 HX Flow chart of 125 HX General Twelve Year Limited Warranty720 606 720 606 BBT North America Maintenance Table see

125HX LP, 125HX NG specifications

The AquaStar 125HX NG and 125HX LP are highly efficient gas tankless water heaters designed to meet the demands of modern households. With their compact size and advanced technology, these units provide an endless supply of hot water while maintaining energy efficiency. Both models cater to natural gas and propane applications, making them versatile options for various installations.

One of the standout features of the AquaStar 125HX series is its ability to deliver a powerful output of up to 199,000 BTUs, ensuring that multiple hot water outlets can operate simultaneously without a drop in temperature. Users can enjoy the convenience of hot showers, laundry, and dishwashing all at once, making it an ideal choice for busy families or households with high hot water needs.

These models incorporate a sophisticated modulating gas valve that adjusts the gas flow based on the demand for hot water. This technology not only optimizes energy consumption but also contributes to extended unit life by minimizing wear and tear on the components. The AquaStar 125HX units also come equipped with a patented electronic ignition system, which eliminates the need for a standing pilot light and reduces gas consumption.

Furthermore, the AquaStar 125HX NG and 125HX LP feature a durable heat exchanger constructed from high-grade copper, which enhances thermal efficiency and prevents corrosion. This ensures a longer lifespan and increased reliability for homeowners. Additionally, the units are compact and wall-mounted, allowing for flexible installation in various spaces, including tight utility closets or outside walls.

Safety is also a top priority, with built-in overheat protection and a freeze protection feature that ensures the unit remains operational even in colder climates. The AquaStar 125HX series operates quietly, allowing users to enjoy the benefits of hot water without the disruptive noise commonly associated with traditional water heaters.

In summary, the AquaStar 125HX NG and 125HX LP are leading choices in the tankless water heater market, combining efficiency, reliability, and innovation. Their impressive output, advanced technologies, and compact design make them suitable for modern living, ensuring homeowners have access to hot water whenever they need it. With these features, AquaStar continues to set a high standard in water heating solutions.
Top Page Image Contents