MAXA HWA1-A 0140, Manual

Page: 18 / 32

HWA1-A
Air/water chillers with axial fans
17
NOTE:
−
If H10 = 15, the remote shutdown of the unit (remote on-off) or from the on-board unit controller, or from the remote
control panel has no effect on sanitary operating mode. The unit will be placed in sanitary mode as setting priority after its
power on. The on-board unit display shows the temperature measured by the sensor placed inside the sanitary water tank.
Once the sanitary cycle is completed, the display returns to show the temperature of the outlet water sensor.
−
If the remote ON-OFF digital input (onoff-onoff terminals) is open, with enablement of the function of domestic hot water
(
H10=1 and H20=6 ), the display on-board unit shows the code " SAN ". Once the sanitary cycle is concluded, the display
returns to show the code " E00 " indicating that the remote ON-OFF contact is open.
−
If H10 = 2 , the remote on-off function disenables the production of domestic hot water and also the operation of the heat
pump in heating and cooling on plant side.
14.2.1 MEMORIZATION OF THE SENSOR IN HEATING MODE
In the case of commutation from water users to the domestic hot water, the temperature sensor changes from a "water outlet
temperature sensor" to a "water tank temperature sensor". For such reason, in heating mode, the last value read by the sensor
will be memorised before changing to DHW mode.
When the DHW thermoregulation is reached, the reference temperature on the plant side will take the value which is previously
memorised.
The memory function will be interrupted:
- When the temperature detected by the sensor becomes lower than the memorized value;
- Or after a period equal to b06 seconds (default 45 seconds).
14.2.2 SANITARY MODE CALL FROM DIGITAL INPUT
In the case where a digital input is configured for sanitary water mode call (instead of the sensor), the heat pump will be placed in
sanitary mode when the digital input is closed (the same behaviour is obtained when DHW temperature sensor < (set of DHW
– Pa
b03 ) and exits from the DHW production when the digital input is open.
Note: If a temperature sensor is installed and configured, this management will be ignored and the thermoregulation will be done
on the basis of the detected temperature by the sensor.
To enable this function, enter at the parameters PRG
→
PSS
→
PRG
→
(introduce the maintainer password)
→
PRG
→
Par
→
PRG
→
CnF.
I/O port – Parameter Value Description Function
H62 28 Digital input for sanitary mode call from
digital input
Close contact
→
Heat pump in sanitary mode.
Open contact
→
Heat pump in plant system
mode.
(*) Otherwise, it is possible to use another digital input.
In the case where a digital input is configured for sanitary water function call (instead of the sensor), the heat pump will be placed
in sanitary mode when the digital input is closed and exits from the DHW production when the digital input is open.
The DHW setpoint of the heat pump is not considered here, its management is the designer
’s responsibility , who must take into
consideration the DHW protection and the configuration of the whole system .
Note : It is possible to invert the polarity of the digital input, for such purposes please contact our technical office.
14.2.3 REGOLATOR IN COOLING
If the DHW temperature is below the sanitary water set - Pa b03, the sanitary valve is activated and the compressor is switched
off. When the safe time period is terminated, the compressor change setting to the nominal frequency for domestic hot water
(see nominal frequency calculation) until achieving set of domestic hot water. At this point, the sanitary valve will stop and then
the compressor will stop. Once the safe time period is terminated, the chiller resumes the normal regulation.
14.2.4 REGULATOR IN HEATING
If the sanitary water temperature is below the sanitary water set - Pa b03 , the DHW valve will be activated without switching off
the compressor which will change frequency to the rated one (see calculation of the nominal frequency of the compressors in
sanitary mode) until the temperature achieves the set of 'sanitary water. At this point, the sanitary valve switched off and the unit
will resume normal operation.
14.2.5 SANITARY VALVE REGULATOR
ON
OFF
DHW temp. sensor
DHW setpoint
Pa b03