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Installation instructions
3 Installation instructions
3.1 Introduction
Please follow these instructions. Failure to follow
instructions may result in:
• Property damage or personal injury
•Improper operation
• Heater damage
• Loss of warranty.
Please contact Bosch Water Heating with any
questions.
3.2 Proper location for installing your
heater
Carefully select the location of the water heater. For
your safety and for proper heater operation, you must
provide combustion air to the heater and a proper
exhaust vent system.
Follow the guidelines below:
B 1. Locate the heater where venting, gas and
plumbing connections are feasible and convenient.
B 2. The hot water lines should be kept short to save
energy. Centrally locating the water heater is best. It
is always best to have hot water lines insulated.
3.3 Heater placement and clearances
The GWH-345/450-ESR is design certified for
installation on a combustible wall (see 3.4 Mounting
installation) provided the floor covering below the
heater is noncombustible. For installations in an alcove
or closet, maintain the minimum clearances to
combustible and non-combustible materials listed
below. See also fig. 5.
A. Top 12 inches (305 mm)
B. Front 4 inches (100 mm)
C. Back 0 inches
D. Sides ½ inches (12 mm)
E. Bottom 12 inches (305 mm)
Clearances from any exhaust vent pipe are dependent
upon the clearance requirements of the stainless steel
vent pipe manufacturer. Single wall sealed stainless
steel (AL29-4C) vent pipe (rated for Category III
appliances) must be used when exhaust venting this
appliance. See 3.6 Venting.
3.4 Mounting installation
B Secure the wall mounting bracket provided with the
heater to a wall surface.
If wall is a stud wall sheathed with plasterboard, it is rec-
ommended that support board(s), either 1x4’s or
1/2" (minimum) plywood first be attached across a pair
of studs. Then attach the heater’s bracket to the upper
support board. The heater should be kept level on the
wall surface. See Fig. 10.
Warning: The water in this
recirculating water heater is cold and
always remains cold except for the
times the burners are on. In the event of
power outage in conjunction with
freezing temperatures, it is
recommended that the heater be
drained to prevent heater from freezing.
See chapter 9 for draining instructions.
Warning: Flammable materials,
gasoline, pressurized containers, or any
other items or articles that are potential
fire hazards must NOT be placed on or
adjacent to the heater. The appliance
area must be kept free of all
combustible materials, gasoline and
other flammable vapors and liquids.
Warning: before starting installation:
B check that there are no loose parts
inside the appliance
B check that the gas type of the heater
matches the gas supply you will be
connecting to the heater.
B ensure that gas pipe, gas valve, fan and
burner have no damage and are proper-
ly fitted.
i
Front cover should be removed (see
instructions on page 5) in order to inspect
components visually.
Warning: Do not install this appliance
on a carpeted wall. The heater must be
mounted on a wall using appropriate
anchoring materials.