Bosch PROTANKLESS GWH 345/450 ESR - Manual (Page 28)

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Operating instructions
4.4 Power
On
To start the appliance:
B press the ON/OFF button.
LED (fig. 31) goes orange.
When the burner is working, the LCD display shows
the symbol
.
Fig. 32
Off
To shut down the appliance:
B press the ON/OFF switch to OFF position.
4.5 Recirculating water temperature
Water temperature can be regulated in a range of
113°F to 190°F. The heater modulates the burner flame
according to current demand selected on left knob.
To select water temperature:
B Rotate recirculating water temperature selector
in order to change heating recirculating temperature
(ranging from 113°F to 190°F).
The display will show this symbol
and blink the
selected temperature.
If the burner is on, symbol
goes ON.
Fig. 33 Recirculating water temperature adjustment
4.6 Temperature and hot water flow
Choose one the following:
• If using a tank mounted Aquastat, set temperature on
Aquastat control (left knob should be in maximum
position).
• To activate and use the appliance domestic
temperature dial, a 12 kOhm thermistor is required
(part number 8 714 500 034) (See 2.6, Page 8 for
wiring diagram).
B Connect the 12kOhm thermistor blue wire to the
DHW NTC terminal block.
Install the sensor in the tank well.
Hot water temperature can be set from 50°F to 158°F
using hot water temperature selector
(Fig. 34).
Fig. 34 Hot water temperature adjustment
4.7 Freeze protection
B Do not disconnect the electric supply from heater.
B Do not install in unheated areas which can
experience freezing temperatures.
B Do not use non-potable additives like glycol.
Freeze protection
Freeze protection is always assured by the operation of
the appliance.
If the primary NTC (temperature) sensor detects
temperatures 9°F below the selected temperature, the
appliance starts on minimum power until the sensor
reads selected temperature.
In case of minimum setpoint it will start at 41°F.
Thermostat
knob position
DHW
temp.
Min. approx. 50°F (10°C)
Max. approx. 158°F (70°C)
Table 14 Domestic hot water temperature
adjustment