Technical data

BWR MTD2
BWR_MTD2_0011_0121_201110_EN HFC 410A
7
SOURCE PUMP OPERATION
The BWR unit’s electronics can manage condenser or evapora-
tor operation precisely and reliably, controlling the flow of water
through the heat exchanger by modulating operation of the
ground source pump.
The condensing/evaporating pressure is read by a dedicated
sensor installed on the unit; the electrical signal is then sent to
the electronic controller that, based on the configuration para-
meters, modulates operation of the ground source pump by
adjusting power supply voltage.
DOMESTIC HOT WATER PRODUCTION
The controller manages domestic hot water production using a
3-way valve installed outside of the unit, deviating the flow of
hot water to the DHW storage tank, which must be suitably
sized according to the type of usage.
Production is enabled when the water temperature inside the
DHW storage tank (probe BT8) is less than the DHW set point.
The production of domestic hot water is guaranteed in both
summer and winter, according to the operating limits shown in
this manual.
If heat pump operation is expected outside of the limits, consid-
er using a supplementary source of heat, managed directly by
the controller.
An electric heater should be installed inside the DHW storage
tank to ensure the temperature does not fall below 10°C in the
event of extended periods of heat pump inactivity (standby).
LEGIONELLA PREVENTION FUNCTION
The Legionella prevention function ensures the elimination of
the Legionella bacteria that reside in domestic water storage
tanks.
The temperature and duration of the Legionella prevention
cycles to eliminate bacteria are typically:
• 2 minutes > 70°C
• 4 minutes > 65°C
• 60 minutes > 60°C
The Legionella prevention cycles are managed directly by the
controller, enabling the heater in the domestic hot water storage
tank domestic, with the possibility to set the duration, tempera-
ture, day and time.
AUXILIARY RESOURCES
The controller can manage devices outside of the heat pump,
such as electric heaters or boilers.
The auxiliary device can be used to replace or supplement heat
pump operation, as selected by parameter.
In the first case, the external device is activated to replace the
heat pump during operation outside of the limits shown in para-
graph 6, “Operating limits”, or alternatively if the compressor
shuts down due to a fault.
In supplementary operation, the external device is activated at
the same time as the compressor so as to satisfy the building’s
thermal demand, based on the trend in water temperature, as
shown in the graph.
OFF
ON
ON
OFF
Auxiliary
device
Compressor
Auxiliary device activation delay time
Integral term calculation
System water control
set point
Actual water
temperature
System HP control
hysteresis