Carel k.Air, User Manual, Page: 89 / 192

89
Functions k.air +030220981 rel. 1.2 - 01.12.2020
30220980_210_R01
ON
OFF
ON
OFF
CMP
ON_OFF
Rev_cycle_valve
ON
Def_end_thr
Def_strt_thr
Def_strt_thr- ∆
OFF
Def_req
Ext_exch_tmp
Byp_dmp
CMP
BLDC
FAN
0%
100%
min%
0%
100%
0%
100%
min%
Req%
D_b_cycle_rev Strt_del
D_a
cycle_rev
1 2 3
Key
Ext_exch_tmp(*) Outside coil temperature
Def_end_thr
End defrost threshold
Def_strt_thr Start defrost threshold
Δ Evaporation temperature delta
D_b_cycle_rev Delay before reversing cycle
A Defrost by reversing the cycle
D Post-dripping
Def_reg Defrost request
Byp_dmp Heat recovery bypass damper
Rev_Cycle_valve Reversing valve
Strt_del
Delay at start-up
D_a_cycle_rev Delay after reversing cycle
B Decreased compressor cap. for
defrost
CMP On/off compressor
CMP_BLDC BLDC compressor
Fan Fan
Cmp_off _t Compressor OFF time
t time
C Dripping
Fig. 9.av
(*) The start defrost temperature = evaporation temperature, end defrost temperature = condensing temperature.
9.25.1 P late heat recovery unit
The bypass damper opens according to the outside temperature value so as to reduce the amount of fresh outside air entering
the heat exchanger. It continues to be crossed by the fl ow of warm exhaust air (~20°C), so as to assist defrosting.
30220980_163_R01
OFF
Byp_dmp
thr_min
Byp_dmp
thr_max
ON
Ext_T
Bypass
damper
30220980_162_R01
100%
0%
Ext_T
Bypass_
dmp_op (%)
Byp_dmp
thr_min
Byp_dmp
thr_max
Key
Bypass_
dmp_op Bypass damper opening
Byp_dmp_
thr_max Bypass damper maximum
opening threshold
Byp_dmp_
thr_min Bypass damper minimum
opening threshold
Ext_T Outside temperature
Fig. 9.aw
9.25.2 Thermal wheel
To prevent activation of frost protection, the thermal wheel, starting from the minimum bypass damper opening threshold,
decreases speed until stopping, reducing heat exchange between exhaust air (warm) and fresh air (cool).
30220980_176_R01
100%
0%
Ext_T
H_wheel_speed
Byp_dmp
thr_min
Byp_dmp
thr_max
Key
H_wheel_speed Thermal wheel speed
Byp_ dmp_ thr_ max Bypass damper maximum opening threshold
Byp_ dmp_ thr_ min Bypass damper minimum opening threshold
Ext_T Outside temperature
Fig. 9.ax