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ENGLISH
ir33 +030220441 - rel. 2.0 - 01.05.2006
7.4 Defrost management parameters
Code Parameter MSYF ** UOM Type Min Max Def.
d0 Type of defrost -SYF fl ag C 0 4 0
dI Interval between defrosts -SYF hours F 0 250 8
dt1 End defrost temperature, evaporator -SYF °C/°F F -50 200 4.0
dt2 End defrost temperature, aux evap. -SYF °C/°F F -50 200 4.0
dP1 Maximum defrost duration, evaporator -SYF min F 1 250 30
dP2 Maximum defrost duration, aux evap. -SYF min F 1 250 30
d3 Defrost start delay -SYF Min C 0 250 0
d4 Enable defrost on start-up -SYF fl ag C 0 1 0
d5 Defrost delay on start-up -SYF min C 0 250 0
d6 Display on hold during defrost -SYF - C 0 2 1
dd Dripping time after defrost -SYF min F 0 15 2
d8 Alarm bypass after defrost -SYF hours F 0 15 1
d8d Alarm bypass after door open -SYF hours/
min
C02500
d9 Defrost priority over compressor protectors -SYF fl ag C 0 1 0
d/1 Display of defrost probe 1 MSYF °C/°F F - - -
d/2 Display of defrost probe 2 MSYF °C/°F F - - -
dC Time base for defrost -SYF fl ag C 0 1 0
d10 Compressor running time -SYF hours C 0 250 0
d11 Running time temperature threshold -SYF °C/°F C -20 20 1.0
d12 Advanced defrost -SYF - C 0 3 0
dn Nominal defrost duration -SYF - C 1 100 65
dH Proportional factor, variation in dI -SYF - C 0 100 50
Tab. 7.e
Important warning: afor the set times to become immediately operational, the instrument needs to be
turned off and on again. If this operation is not carried out, timing resumes operation the next time it is
used.
d0: Type of defrost
For the instruments fi tted with defrost relays:
• d0=0 electric heater defrost by temperature;
• d0=1 hot gas defrost by temperature;
• d0=2 electric heater defrost by time, Ed1 and Ed2 not displayed;
• d0=3 hot gas defrost by time, Ed1 and Ed2 not displayed.
Defrosts can be performed for all models:
• by temperature, using the defrost probe fi tted on the evaporator. In any case, the defrost will be
stopped after a maximum set safety time (dP1 and dP2). The warnings Ed1 and Ed2, “end defrost due
to maximum duration” (parameter ‘A8’) can be disabled;
• by time: without the defrost probe;
• by time with temperature control: based on the evaporator temperature, the function is similar to the
mode where d0=0. Once the temperatures dt1 and dt2 (end defrost) have been reached, the defrost
does not end completely, and the controller reactivates the defrost output if the temperature falls
below dt1 and dt2. This occurs for the entire duration of the defrost set using the parameter dP.
Note:
• model S does not have a defrost relay, and consequently the defrost can only be performed by
stopping the compressor and selecting end of defrost by time or temperature. If the alarms Ed1 and
Ed2 are not disabled, when activated, they can be cancelled by pressing * and AUX together for more
than 5 seconds, or automatically at the start of the next defrost operation.
• if control with two compressor steps is selected (with or without rotation, H1= 12 or 13) the defrost is
performed acting on both steps.
Default: d0=0 => electric heater defrost by temperature.
dI: Interval between defrosts
The defrosts are performed cyclically at an interval equal to the value of dI in hours (or minutes, see
parameter dC), counted from the end of the previous period. The duration of the defrost therefore does
not therefore affect the interval between defrosts. The interval dI is also maintained when the unit is OFF.
If the interval dI expires when the controller is OFF, when it is started again a defrost is performed.
If dI =0 => the defrost is never performed except when forced from the keypad (manual defrost), from
the supervisor or from the digital input (see parameter A4), or from the Real Time Clock.
Important: PTo ensure regular defrosts, the interval between defrosts must be greater than the maxi-
mum defrost duration, plus the dripping time and post-dripping time.
Note: during the defrost, the temperature alarms are disabled.
Default: dI =8 hour.
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