Carel k.Air, User Manual, Page: 84 / 192

84
Functions
k.air +030220981 rel. 1.2 - 01.12.2020
Deactivation
Frost protection is deactivated when the frost protection thermostat switches or the value read by the frost protection probe is
greater than the frost protection threshold plus a settable diff erential.
ACTIVATION BYTHERMOSTAT ACTIVATION BYPROBE
ON
OFF
ON
OFF
ON
OFF
ON
OFF
t
t
t
t
Antifr_therm
Antifreeze
Antifreeze alarm
Unit
Al_delay Wd
30220980_159_R01
S_ Ed
Antifr_pr_thr
S_pr_thr
ON
OFF
ON
OFF
ON
OFF
t
t
t
t
t
Antifreeze
Antifr_pr
Antifreeze alarm
Unit
Al_delay Wd
30220980_160_R01
Fig. 9.am Fig. 9.an
Key
Antifr_therm Frost protection thermostat
Antifreeze alarm Frost protection alarm
Wd Warning delay
t time
Antifreeze Frost protection
Unit Unit status
Al_delay Frost protection alarm
Key
Antifr_pr Frost protection temperature
Antifr_pr_thr Frost protection temperature threshold
Antifreeze alarm Frost protection alarm
Wd Warning delay
S_pr_th Supply probe threshold
Antifr_pr Frost protection temperature
Antifr_pr_thr Frost protection temperature threshold
Antifreeze alarm Frost protection alarm
Wd Warning delay
S_pr_th Supply probe threshold
Control
If the condition for ending frost protection does not occur before the “Warning delay” time, the unit goes into frost protection
status and the corresponding procedure is started.
9.23.1 F rost protection procedure in normal operation
The unit is in frost protection status.
1. The supply fan (and return fan, if featured) goes to the set speed if there is a mixing damper, otherwise it switches off , while the
heating/cooling/mixed coil valve opens to the value set for the parameter.
2. if there is a mixing damper, this is opened completely, the fresh air and exhaust dampers are closed completely;
3. the fans are switched off . If there is an electric heater, this is switched off fi rst and then the fans are switched off after the
post-ventilation time.
Frost prevention
The frost prevention function aims to bring the unit back to normal control by reducing the supply of fresh outside air.
Procedure:
The fresh air and exhaust dampers start closing and the fans begin to decrease speed until reaching the condition for activating
frost protection.