Carel k.Air, User Manual, Page: 75 / 192

75
Functions k.air +030220981 rel. 1.2 - 01.12.2020
FREEHEATING (heating requestactive)
30220980_167_R01
OFF
Set
RetT ExtT
ON
T
Enable
delta_fh
30220980_168_R01
OFF
Set
RetT ExtT
ON
T
Enable
delta_fh
Key
RecT Return temperature
ExtT Outside temperature
T Temperature
Set Set point
delta_fh Freeheating activation delta
delta_fc Freecooling activation delta
Fig. 9.ag
ON : ExtT-RecT> delta_fh ; OFF : ExtT-RecT<0
R if D escription D ev Min Max UoM D ir Modbus BAC net
U N IT
Ac11 Freecooling activation delta 3.0 0.0 20.0 K R/W HR1323 AV2831
Freeheating activation delta 3.0 0.0 20.0 K R/W HR1324 AV2832
Ac40 Free cooling PID parameters - Proportional gain 8.0 0.0 999.9 - R/W HR1325 AV2833
Free cooling PID parameters - Integral time 120 0 999 - R/W HR1326 PIV2834
Ac42 Free heating PID parameters - Proportional gain 8.0 0.0 999.9 - R/W HR1327 AV2835
Free heating PID parameters - Integral time 120 0 999 - R/W HR1328 PIV2836
Tab. 9.ac
R if D escription D ev Min Max UoM D ir Modbus BAC net
FANS
Ba15 Enable fan regulation in case of FreeCooling/FreeHeating FALSE 0 1 - R/W CS247 BV247
Ba33 Fan temperature regulation PID parameters - Proportional gain 8.0 - 999.9 999.9 - R/W HR1513 AV3014
Fan temperature regulation PID parameters - Integral time 120 0 65535 - R/W HR1514 PIV3015
Tab. 9.ad
R if D escription D ev Min Max UoM D ir Modbus BAC net
DA M P E RS
Ca12 Enable dampers regulation in case of FreeCooling/FreeHeating FALSE 0 1 - R/W CS290 BV290
Tab. 9.ae
The activation temperature diff erentials are needed to determine how effi cient it is to use freecooling/freeheating, considering
that the greater the diff erence between the outside air temperature and the return temperature, the more effi cient the action
will be.
For units with modulating fresh air dampers, the conditions for activating freecooling/freeheating are the same, however free-
cooling/freeheating is considered as the fi rst stage in cascade control. The controller adjusts the modulating fresh air damper (in
sync with the mixing damper), and the bypass damper, if fi tted, is opened completely.
Note:
when the freecooling activation conditions are active, the heat recovery stage is disabled..