Carel ir33+ small wide User Manual page 33

1. Heater defrost (d0 = 0, 2, 4): duty cycle
The duty cycle refers to the default values of parameters F2 and F3.
C
L
F
S
V_Pd
M
T
V2
Fig. 6.n
REFRIG PUMP
DOWN
ON
CMP
OFF
ON
V_Pd
OFF
ON
FAN
OFF
ON
RES
OFF
Fig. 6.o
Key
CMP Compressor
V_Pd Pump down valve
FAN Evaporator fan
RES Heater
E Evaporator
C Condenser
V2 Thermostatic expansion valve
F Filter-drier
t Time
Note:
•
in pump down mode, the behaviour of the fan is determined by F2;
•
in defrost, the behaviour of the fan is determined by F3.
2. Hot gas defrost (d0 = 1, 3): duty cycle
The duty cycle refers to the default values of parameters F2 and F3.
C
L
ir33+
F
S
V_Pd
T
M
V2
E
Fig. 6.p
CMP
ir33+
S2
E
DEF DRIP POST DRIP REFRIG
(dd) (Fd)
c8
t
Refrig Cooling
Pump down Pump down stage
Def Defrost
Drip Dripping
Post drip Post-dripping
S2 Defrost probe
L Liquid receiver
S Liquid gauge
V_def
M
CMP
S2
Note: the defrost output (DEF) is used to control the hot gas valve
V_def.
REFRIG PUMP
DOWN
ON
CMP
OFF
ON
c8
V_Pd
OFF
ON
FAN
OFF
ON
V_def
(HOT GAS)
OFF
Key
CMP Compressor
V_Pd Pump down valve
FAN Evaporator fan
V_def Hot gas valve
E Evaporator
C Condenser
V2 Thermostatic expansion valve
F Filter-drier
t Time
The defrost starts:
•
by setting the event and the start mode, with a maximum of 8 defrosts
each day (parameters td1 to td8). The real time clock (RTC) must be
available;
•
from the supervisor, which sends the defrost call to each controller via
the serial line;
•
from the keypad.
The defrost ends:
•
when the defrost probe measures a temperature greater than the end
defrost temperature dt1;
•
when no defrost probe is used, the defrost ends after a maximum time,
set by parameter dP1.
Maximum time between consecutive defrosts
Par. Description
dI Maximum time between consecutive defrosts
0 = defrost not performed
Parameter dI is a safety parameter used to perform cyclical defrosts
every "dI" hours, even without the Real Time Clock (RTC). It is also useful
if the RS485 serial network is disconnected. At the start of each defrost,
irrespective of the duration, an interval starts being counted. If this
interval exceeds dI without a defrost being performed, one is started
automatically. The count is always active even if the controller is OFF.
33
ENG
DEF DRIP POST REFRIG
DRIP
c8
t
Fig. 6.q
Refrig Cooling
Pump down Pump down stage
Def Defrost
Drip Dripping
Post drip Post-dripping
S2 Defrost probe
L Liquid receiver
S Liquid gauge
Def Min Max UOM
8 0 250 hr/
Tab. 6.k
ir33plus +0300028EN rel. 1.1 - 05.05.2017
min