UAB AMALVA we reserve the right to make changes without prior notice
18
EN
V2-C5-15-03-v1
EHA – exhaust air
ETA – extract indoor
SOA – outdoor intake
SA – supply air
RCA – recirculated air
Using Verso RHP devices with recirculation section the supply air temperature sometimes can‘t be supported. For
this it is recommended to choose an additional heater / cooler to ensure the supply air temperature. Otherwise,
the supply air temperature will not reach set point.
Heat pump defrosts control
HP operation at low outdoor air temperatures and high indoor humidity, potential evaporator freezing (in exhaust
air flow). At the time on the heat exchanger forms white frost, snow, ice. As a result:
•
Increases air pressure drop through the heat exchanger;
• Decreases heat exchanger efficiency.
To manage the freezing and defrosting process the controller C5 sets the defrost function.
This function is activated when:
•
The device operates in HP mode.
•
Air temperature after the evaporator is negative.
Additional (to the standard controller C5 elements) this function has extra elements:
• Pressure transducer for air flow pressure drop through the evaporation heat exchanger;
•
Air temperature sensor after the evaporator;
•
Refrigerant „by pass“ line and valve.
The pressure transducer measures the pressure drop through evaporation heat exchanger. The initial differential
pressure values (clean heat exchanger) controller will be set automatically. These values depends on the ventila-
tion rate and evaporator construction.
When differential pressure reaches a critical level (two times the initial value) initiated defrost process:
•
Opens „by pass“ valve and hot refrigerant is pumped into the evaporator;
• Reduces rotation speed (efficiency) of the rotary heat exchanger, in order to maintain a + 8 °C after the rotary
heat exchanger;
• The compressor starts to work the maximum possible efficiency.
In active defrost function and tasks within a span of absent recorded freezing – starts the short- preventive de-
frosting.
The compressor capacity is limited by the minimum and maximum refrigerant pressure and air flow.
When system pressure are near the lower values, reduces compressor efficiency (speed). When reaches the
minimum permissible compressor capacity and pressure limits the problem remains – the compressor stops. After
some time the compressor switches on again and monitors coolant pressure. If the pressure reaches a critical
value - the compressor stops. If it happens three times a certain time – after that compressor no longer activates
and controller shows message: “Low compressor pressure” or “High compressor pressure”, respectively.
The drop eliminator and evaporator pan is with heating cable, which prevents the formation of ice and it facilitates
the removal of condensate. The heating cable is switch on when air temperature after evaporator is less than 0 °C.
Units are filled with f-gas. Service should be carried out in accordance
with the local laws.
