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Appliance details
2 Appliance details
2.1 Features
Parts
• Sealed combustion burner.
Safety
• Ionization flame sensor
• Over temperature protection.
High quality materials for long working life
• Copper heat exchanger
• Compact space saver: mounts on a wall with
supplied bracket.
Features
• LCD screen to display temperatures, burner
operation and error codes
• On/Off button and separate temperature controls for
domestic water heating and recirculating water
• Reset button
• Failure codes for diagnostics and repair
• Freeze prevention cycle.
2.2 GWH-345/450-ESR Specifications
(Technical data)
Approved in US/Canada
Capacity
GWH345 Maximum flow rate: 3.5 GPM (13 l/min) at a
45°F (25°C) rise.
GWH450 Maximum flow rate: 4.5 GPM (17 l/min) at a
45°F (25°C) rise.
Maximum output
GWH345 - 77,900 Btu/h (22.8 kW)
GWH450 - 98,400 Btu/h (28.8 kW)
Maximum input
GWH345 - 95,000 Btu/h (27.8 kW)
GWH450 - 120,000 Btu/h (35.1 kW)
Efficiency in %
GWH345 Combustion efficiency: 82%
GWH450 Combustion efficiency: 81%
Min. Output
GWH345 - 23,900 Btu/h (7 kW)
GWH450 - 35,500 Btu/h (10.4 kW)
Temperature Control
Selection range: 115°F (45°C) - 190°F (90°C)
Gas Requirement
Gas connection (inches) - ¾”
Inlet gas pressure under operation (with a high hot
water flow rate)*
• Propane: 11” - 14” water column
• Natural Gas: 5.5” - 8” water column.
* To measure gas pressure, see Measuring Gas
Pressure, chapter 3.8.
Venting
3" AL 29-4C single wall sealed stainless steel vent
pipe.
See chapter 3.6 for Venting.
Water
• Hot water connection - ¾” NPT
• Cold water connection - ¾” NPT.
Combustion
•NOx ≤ 100 ppm
•CO ≤ 250 ppm
•CO
2
level (see table 8 for correct restrictor
dimension).
Dimensions
• Depth (in): 11 ¾” (300 mm)
• Width (in): 15 ¾” (400 mm)
• Height (in): 27 ½” (700 mm)
• Weight: 47 pounds (21 kg).
Gas types
Natural Gas.
Liquid Propane.
The appliance is not field convertible.
Voltage
120 V AC (50/60 Hz)
Amperage
Idle - 40 mA
Operation - ≤ 1.5 A
Noise
≤ 50 db (A)
Safety devices
• Flame failure device (Ionization flame control)
• Overheat prevention (temperature limiter)
• Pressure switch (blocked vent protection).
i
BOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.