Carel k.Air, Руководство пользователя, Страница: 60 / 192

60
Functions
k.air +030220981 rel. 1.2 - 01.12.2020
Type of heating/cooling changeover D escription N ote
Manual from k.water The unit changes mode when selected on k.water only with k.water
connected via Ethernet
Auto from control probe The unit automatically changes mode so as to reach the main set point
Auto from control probe + mixed coil
limit from DIN The unit automatically changes mode so as to reach the main set point,
however the mixed coil can only be used based on the status of the
heating/cooling digital input. This mode is useful when the operating
mode needs to change over, and therefore stages such as heat recovery
or freecooling can be used, yet the mixed coil is still supplied by a sour-
ce that is not consistent with the temperature control requirements.
Example: mixed coil supplied with hot water, yet freecooling in winter
required. with mixed coil only
Auto from control probe + mixed coil
limit from water temp. probe. The unit automatically changes mode so as to reach the main set point,
in the same way as for mixed coil limit mode by DIN, however in this
specifi c case the coil is enabled directly by measuring the supply water
temperature. This mode allows precise control of consistency between
the required mode and the operating capacity of the mixed coil. Activa-
tion thresholds must be set based on the water temperature (Ac28) with mixed coil only
Tab. 9.n
Forced automatic heating/cooling changeover based on outside temperature
For all types of automatic heating/cooling changeover, the operating mode can be defi ned based on the outside air tempera-
ture. This is useful in avoid changing mode in the most critical periods in summer and winter. The thresholds are set on screen
Ac24.
Unit operation based on the mode, heating or cooling.
In cooling or heating mode, the unit operates with the corresponding set points and limits; however, the current set point can
be changed on the specifi c screen (Qc01) or on the th-Tune terminal (if connected). The unit works so as to maintain the desired
temperature, by activating the appropriate devices. Once the set point has been reached, the devices are gradually deactivated,
following the priority described in the paragraph on “Temperature control”. When the mode is changed, the default set point
becomes the new control set point.
For example, if the unit is in heating mode with Set = 20°C and it then switches to cooling mode, the new set point will be the
default cooling set point. The control set point for the current mode can still be set on th-Tune or pGDE.
The unit can immediately switch between heating and cooling in manual mode, while for automatic changeover, a delay can
be set in the Set point menu (Qc04).
For supply or room + supply control, automatic heating/cooling changeover takes eff ect after fi rst having verifi ed the
room or return temperature, and consequently the adjustment to the supply set point by the off set will be negative in cooling
mode and positive in heating mode (see the paragraph on “Temperature control”). In this specifi c case, during the transients, it
should be noted that following a change in mode (due to the return or room temperature), supply temperature control also
changes to the new mode, however does so gradually using the new calculated set point.
R if D escription D ev Min Max UoM D ir Modbus BAC net
U N IT
Ac22 Machine type (0: COOLING; 1: HEATING; 2: COOL/HEAT) 2 0 2 - R/W HR1310 PIV2818
Machine type cooling/heating enabled - 0 1 - R DI700 BV1158
Unit cooling heating mode confi guration 0 0 6 - R/W HR1311 PIV2819
Ac24 Cooling external temperature threshold 28.0 - 99.9 99.9 °C R/W HR1312 AV2820
Heating external temperature threshold 18.0 - 99.9 99.9 °C R/W HR1313 AV2821
Ac28 Cooling/Heating coil water temperature cooling threshold 15.0 - 99.9 99.9 °C R/W HR1314 AV2822
Cooling/Heating coil water temperature heating threshold 25.0 - 99.9 99.9 °C R/W HR1315 AV2823
Tab. 9.o