© Termo-tehnika, d.o.o.
17-16-27-3033-00
10
07/2016
5.2 Operating principle
The cooling system of the heat pump is a closed circuit system where the coolant R134a
circulates as heat exchanger. At lower pressure and temperature (i.e. 10°C) the coolant is
evaporated in the evaporator of the heat pump and thus removes heat from the air. Afterwards,
the compressor compresses the coolant to a higher pressure, this results in the raising of the
coolant temperature to a level higher than the water temperature in the DHW. The coolant then
releases the heat in the condenser into the water and condenses as a result. With the
expansion of the coolant the pressure and temperature in the coolant fall to their initial level,
completing the circular process. This process is repeated throughout the heat pump’s
operation.
Buffer tank for DHW
Additional heat pump WPF2-1 is a generator of the heat pump intended to be installed to the
water buffer tank with a side flange
φ
180mm/8.
Additional electrical heater
The additional electrical heater EH with 1.2 kW functions as:
safeguard against vaporizer freezing.
In case the air temperature in the room is too
low for the heat pump’s operation, the EH turns on automatically;
it is the
reserve source
in case of a malfunction of the heat pump generator.
Anti-freeze sensor
The regulator of the heat pump senses the air temperature flowing through the evaporator. In
case the air temperature is lower than 7°C (factory setting), it performs a safety shut-down of
the device for at least 30 minutes. In this case heat pumps with electrical heaters automatically
switch to heating with the electrical heater, devices with a DHW switch to heating with DHW
(turning on the circulation pump).
The operation and safety thermostat of the electrical heater
The electrical heater has its own operation and safety thermostat which is limited to 85°C.
CAUTION
When the electrical heater is in operation, it heats water to approx. 65°C.
Because it only heats the upper part of the DHW, the temperature regulator does
not show correct values because its sensor is placed at the bottom part of the
DHW and usually senses the colder part of the water. When heating with DHW
or solar collectors, water can be heated above 85°C which triggers a shut-down
of the safety thermostat of the electric heater. In this case the electrical heater
has to be manually reset. To reset the electrical heater, call an authorised
maintenance worker.
