Zwb; Setting The Dhw Temperature; Setting Manual Summer Mode; Setting Frost Protection - Bosch Greenstar Series Installation And Service Instructions For Contractors

8.7 ZWB...-3A appliances (combi boilers):

Setting the DHW temperature

▶ Set the DHW temperature on the DHW thermostat
The set DHW temperature flashes on the display for 30 seconds.
3 4
2 5
1 6
max
Fig. 67 Set the DHW temperature (ZWB...-3A)
DHW thermostat Typical DHW temperatures
min approx. 104 °F (40 °C)
e approx. 122 °F (50 °C)
max approx. 140 °F (60 °C)
Table 25 Typical DHW temperatures for ZWB...-3A appliances
ECO button
Pressing and holding the ECO button until it lights up switches between
Comfort mode and Economy mode.
• Comfort mode (default setting)
The appliance is continually maintained at the set temperature.
Consequently, DHW draws are immediate, however the appliance
may run even if no DHW is being drawn.
• Economy mode, ECO button lights up
– DHW is only generated when DHW is drawn.
– On demand: Quickly open and close a DHW tap to signal the
appliance to heat to the selected temperature. After a short wait
DHW will be available.
The DHW on demand signal allows maximum gas and water savings.
8.8

Setting manual summer mode

In summer mode or warm weather shut down (WWSD), the heating zone
pump and consequently central heating are switched off. DHW
generation remains active following the DHW program.
See also the warm weather shutdown (WWSD) feature in the operating
instructions for the heating control included in the scope of delivery.
Greenstar – 6721822579 (2021/01)
.
reset
eco
4
3
2 e
1
6
max
6 720 641 933-55.1O
NOTICE
Heating system at risk of freezing.
In manual summer mode, only the appliance is protected from freezing.
▶ Observe frost protection measures where there is a risk of frost (
chapter 8.9).
▶ Note the supply temperature controller setting
▶ Turn the boiler high limit dial
.
3
5
2
1 6
max
Fig. 68 Summer mode
For further information, see the operating instructions for the heating
control included in the scope of delivery.
8.9

Setting frost protection

Frost protection of the heating system:
▶ Leave the appliance switched ON; set the boiler high limit to at least
95 °F (35 °C) (position 1,  Tab. 22, page 51).
3
5
2
1 6
max
Fig. 69 Frost protection of the heating system
-or-
▶ If you want to leave the appliance switched OFF: Mix Bosch-approved
anti-freeze into the heating water ( Tab. 29, page) and drain the
DHW circuit.
For further information, see the operating instructions for the heating
control included in the scope of delivery.
Frost protection of the DHW tank:
▶ Leave the appliance switched ON; set the boiler high limit to at least
95 °F (35 °C) (position 1,  Tab. 22, page 51).
▶ Turn the DHW thermostat
(50 °F (10 °C)).
3 4
2 5
1 6
max
Fig. 70 Frost protection for the DHW tank
Commissioning
.
counterclockwise as far as it will go:
reset
eco
3 4
e
2
6
1
min
max
reset
eco
3 4
e
2
6
1
min max
6 720 641 933-68.1O
counterclockwise as far as it will go
reset
eco
3
e
2
1 6
min
max
6 720 615 065-15.1O
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