Carel IR32M Manual page 23

d4: Defrosting at power ON
It activates a defrost as the power supply is switched on. A request to defrost on start-up has priority over
insertion of the compressor and over activation of a continuous cycle. Possible values are:
0 = no, defrosting on start-up of equipment;
1 = yes, defrost is effected on start-up.
Commanding a defrost as the power supply is switched on can be useful in certain particular situations, for
example if the installation suffers from frequent power break-downs. If there is a power failure, the internal
clock which calculates the intervals between two defrosts will be set back to zero. In an extreme case, if the
frequency of power failure were to be greater than the frequency of defrosting (for example a power failure
every 8 hours with a defrost interval of 10 hours), control would never command a defrost. In such a
situation it is better to activate defrosting as the power comes on, especially if defrosting is set at a
temperature (evaporator sensor) intended to avoid unnecessary defrostings or if their duration is reduced.
In the case of multi-unit installations, if defrosting at power-on is chosen, it can happen that when power is
restored, all units begin defrosting at the same time, therefore the supply can be overloaded. To avoid this
consequence, use can be made of parameter d5, which permits an initial delay in defrosting; this delay
obviously has to be different for each unit. Default: d4=0 (no defrost at power-on). Available on IR32S,
IR32Y, IR32P and IR32C.
d5: Delay of defrost at power-on or start of Multi-function
This parameter sets the time which is to elapse between the controller power on and the start of defrosting.
When digital input is used, either to initiate defrosting (see parameter A4=3) or to convey a defrosting
command from an external contact (see parameter A4=4), this parameter represents the delay occurring
between the initiation of defrosting, or a request for it, and its actual commencement. The digital input for
defrosting (see parameter A4) can be usefully employed to carry out defrosting in real time. It is sufficient to
connect a timer at the multifunction digital input (see parameter A4). Defrosting will be activated when the
timer contacts close. Where several units are connected to the same timer, we suggest to use the parameter
d5 to delay the various defrostings, so as to avoid any overload on the supply. Furthermore, to avoid
unwanted defrosting being commanded by the equipment internal clock, we suggest set at 0 to the
parameter dI, (defrosts only from keypad or from multi-function contact).
Default: d5=0 (no delay in defrost at power-on or from multi-function input).
Available on IR32S, IRDRSE/S0, IR32Y, IR32P, IR32C and IRDRC.
d6: Blocking display during defrosting
This parameter gives consent to block the display of ambient temperature at the last value read before
defrosting began. Display resumes normally when the measurement first reaches the setpoint o, or in any
case within the time set as "alarm cut-out during defrost (parameter d8). If the display is not blocked during
defrosting the equipment will display the signal dF rather than the value received from the control sensor.
This is to indicate that a possibly high temperature is due to the defrosting process.
Default: d6=1 (during defrosting the display shows the last temperature read before defrosting began).
Available on IR32S, IR32Y, IR32P and IR32C.
dd: Dripping time
This parameter makes it possible to close down the compressor and the evaporator fans after a defrosting,
so as to hasten the dripping from the evaporator. The value of the parameter indicates the minutes of shut-
down. If dd=0, no dripping time is provided for, with the result that the compressor will be re-activated
immediately defrosting is over.
Default: dd=2 minutes. Available on IR32S, IRDRSE/S0, IR32Y, IR32P, IR32C and IRDRC.
Parameter with direct access from remote control.
d8: Period of alarm cut-out after defrosting and/or open door
This indicates the time for which a high temperature alarm will be inhibited at the end of a defrosting and/or
after the door of a store-room has been opened; in the case of Multi-function input being connected to the
door-switch (see parameter A4).
Default: d8=1 hour of cut-out. Available on IR32S, IRDRSE/S0, IR32Y, IR32P, IR32C and IRDRC.
Note: see the following chapter "Notes for the new release" to a more detailed description of this parameter
functionalities, effective for the instrument with serial number greater than 100,000)
22 Cod. +030220151 - Rel. 2.1 - 04/09/98