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Specifications - Bosch 38B LP Installation And Operating Instructions Manual

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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 trans-
fer 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 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.
- High Quality Materials for Long Working Life.
- Copper heating coils for endless supply of hot water.
- Safety thermocouple at pilot burner.
- Automatic overheating protection shut-off sensor.
- 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
- Easy pilot flame lighting with push button piezo ignition.
BOSCH is constantly improving our products, therefore
specifications are subject to change without prior
This heater is packed securely. The box includes two water connection fittings, a gas pressure regulator, a gas supply
elbow with gasket, a gas shut off valve, a pressure relief valve, two hooks for hanging the heater, this manual, a warranty
statement 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.
AquaStar 38B LP and 38B NG Specifications
Gas Input max.: 40,000 Btu/hr
min.: 20,000 Btu/hr
Water Connection 1/2" Thread fitting NPT
H x W x D 25 3/8" x 10 5/8" x 9 1/8"
Vent 4"
Gas Connection 1/2" NPT thread
Min. Water Pressure 13 Psi at 1.3 GPM
Max. Water Pressure 150 Psi
Shipping Weight 20 LB
Net Weight 18 LB
0.5 GPM at 90 ° rise
1.3 GPM at 45 ° rise
Min. Water Flow 1/2 gal/min
LP GAS Supply Pressure
(before Aquastar regulator)
Required LP GAS Pressure at inlet tap while
Aquastar is operating:
LP GAS Burner Manifold pressure while Aquastar is
operating at maximum input:
Natural Gas Supply Pressure
(before Aquastar regulator)
Required Natural Gas Pressure at inlet tap
while Aquastar is operating:
Natural Gas Burner Manifold pressure while Aquastar is
operating at maximum input:
* Inlet gas pressure before Aquastar regulator must not
exceed this value. Pressure may need to be adjusted for
high altitudes, see page 7.
min.: 11" W.C.
max.: 14" W.C.*
10.5" W.C.
9.0" W.C.
min.: 7" W.C.
max.: 14" W.C.*
5.7" W.C.
3.3" W.C.



This manual is also suitable for:

38b ng