Bosch 125B NG User Manual
2
6 720 607 030
This well engineered, gas water heater has all the fea-
tures a water heater should have:
It operates on the principle of heating water instantaneously
“on demand”. When a hot water faucet is opened, cold water
flows through the coils of the heat exchanger in the Aquastar.
This same flow opens the gas valve, and the burners are
ignited by the pilot flame. 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 wa-
ter faucet is an ignition key to turn on the water heater,
giving you control over your hot water energy use. Each
time you turn off your hot water faucet, you also shut off
the water heater.
tures a water heater should have:
It operates on the principle of heating water instantaneously
“on demand”. When a hot water faucet is opened, cold water
flows through the coils of the heat exchanger in the Aquastar.
This same flow opens the gas valve, and the burners are
ignited by the pilot flame. 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 wa-
ter faucet is an ignition key to turn on the water heater,
giving you control over your hot water energy use. Each
time you turn off your hot water faucet, you also shut off
the water heater.
FEATURES
- 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 thermocouple 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 inducer.
- 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.
- Easy pilot flame lighting with push button piezo ignition.
BOSCH is constantly improving our products, therefore
specifications are subject to change without prior notice.
specifications are subject to change without prior notice.
AquaStar 125B LP and 125B NG Specifications
Gas Input max.: 117,000 Btu/hr
min.: 28,000 Btu/hr
Water Connection 1/2” 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 42 LB
Net Weight 39 LB
1.8 GPM at 90° rise
3.7 GPM at 45° rise
Min. Water Flow 1/2 gal/min
LP GAS Supply Pressure
min. 11” W.C.
(before Aquastar regulator)
max.14” W.C.*
Required LP GAS pressure at inlet
tap while Aquastar is operating:
tap while Aquastar is operating:
10.5” W.C.
LP GAS Burner Manifold pressure while
Aquastar is operating at maximum input:
Aquastar is operating at maximum input:
9.0” W.C.
Natural Gas Supply Pressure
min.: 7” W.C.
(before Aquastar regulator)
max.: 14”W.C.*
Required Natural Gas Pressure at
inlet tap while Aquastar is operating:
inlet tap while Aquastar is operating:
5.7”W.C.
Natural Gas Burner Manifold pressure while
Aquastar is operating at maximum input:
Aquastar is operating at maximum input:
4.2” W.C.
* Inlet gas pressure before Aquastar regulator must not
exceed this value. Pressure may need to be adjusted for
high altitudes, see page 10.
exceed this value. Pressure may need to be adjusted for
high altitudes, see page 10.
UNPACKING THE AQUASTAR HEATER
This heater is packed securely. The box includes one water connection fitting, a control knob, 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.
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.