Bosch Model GWH 425 - Manual (Page 14)

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Operation instructions
3.10 Recirculation application
Since recirculation through the heater is not
permissible, the following drawing is provided to outline
a proper recirculation application using the BOSCH
PRO water heater with an Ariston minitank. This
schematic is for illustration only and must not be used
for actual installation without appropriate engineering
and technical advice from a professional properly
licensed in locality where the installation is made.
Fig. 17 Recirculation application
The use of a small electric mini-tank (4-6 gallon size)
should be used for this application and designed so the
pump will circulate the water through the mini-tank and
the building's hot water return loop only. A timed or
thermostatically controlled operation of the pump is
commonly done. The GWH 425 PN should be plumbed
in line before the mini-tank water heater. Contact Bosch
Water Heating if further instruction is needed.
4 Operation instructions
4.1 For your safety read before
operating your water heater
A. This appliance employs a piezo-igniter to light the
pilot burner. When lighting the pilot, follow these
instructions exactly.
B. What to do if you smell gas.
WHAT TO DO IF YOU SMELL GAS
B Close gas valve. Open windows.
B Do not try to light any appliance.
B Do not touch any electric switch; do not use any
phone in your building.
B Immediately call your gas supplier from a neighbors
phone. Follow the gas supplier’s instructions.
B If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to push in the gas control
buttons. Never use tools. If a button will not push in,
check to make sure the buttons are being pushed in the
proper sequence. Follow these instructions exactly. If
control button(s) are jammed, close the heater’s
individual manual shutoff valve and call a qualified
service technician. Forced or attempted repair may
result in a fire or explosion.
D. Do not use this appliance if any part has been under
water. Immediately call a qualified service technician to
inspect the appliance and to replace any part of the
control system and any gas control which has been
under water.
Warning: If you do not follow these
instructions exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
i
Note: Upon initial installation,
existence of air in the gas supply
line and in the water line may
cause some ignition delay. In that
case, repeat the ignition process
until all the air has been purged.