Fujitsu Waterstage Split Comfort 5 Series Installation Manual page 15

■ Domestic hot water (DHW) operating principle
Two domestic hot water (DHW) temperatures can be
set: comfort and reduced.
The default DHW program is set to the comfort
temperature between 00:00 and 05:00 and between
14:30 and 17:00 and to the reduced temperature for the
rest of the day. This optimises electrical consumption
while ensuring comfortable water temperatures.
The reduced temperature setpoint may be useful to
avoid restarting the DHW too often and for too long
during the day.
The production of domestic hot water (DHW) is started
when the temperature in the tank drops to 7°C below
the temperature setpoint.
The heat pump produces the domestic hot water, which
is then additionally heated, if required, by the tank's
electrical backup or by the boiler. To ensure a DHW
setpoint over 55°C, the electrical backup heating must
be left on.
fi g. 11 - Heat pump operating principle
Waterstage Split Comfort DHW Serie / INSTALLATION / 2125 - EN
Air energy
Electrical
energy
consumed
If the contract signed with the energy provider includes
a day/night tariff , the electrical backup is subject to the
supplier's power tariff and the comfort temperature may
only be reached at night.
If no particular contract has been signed, the comfort
temperature can be reached at any time, including
during the day.
The production of DHW takes priority over heating;
nevertheless the production of DHW is managed
by cycles that regulate the amount of time assigned
to heating and production of DHW in the event of
simultaneous demand.
Anti-legionella cycles can be programmed.
■ Fan convectors with integrated control system
Do not use a room sensor in the area in question.
PAC
Dt
Cn
Ev
Cp
COP 4
1 kW
4 kW
Heat produced
PAC - Heating Pump
Ev - Evaporator
Cp - Compressor
Cn - Capacitor
Dt - Expansion Valve
20 °C
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