Carel µC2SE

40
t
1
3
4
6
5
7
2
ENGLISH
µC
2
SE - +030220426 - rel. 2.0 - 03.08.2009
- Type of defrost
d02: establishes the type of defrost.
d02=0: the defrost has a fi xed duration that depends on d07
d02=1: the defrost starts and ends according to the temperature or pressure thresholds, see d03 and d04;
d02=2: the pressure transducer and temperature probe are both located on the outside exchanger; the defrost
starts when the value read by the pressure transducer is below the threshold d03 and ends when the value read by
the temperature probe is above the threshold d04; during the defrost, the pressure probe controls the fan speed,
as in chiller mode, so as to limit the pressure, even if the NTC probe, caked by ice, delays the end defrost. In any
case, after the maximum time allowed for the defrost, the unit will always exit the defrost procedure.
d02=3: enable sliding defrost.
In the event of low outside temperatures, the evaporator pressure or temperature may fall below the threshold set
to start the defrost (d03) even if there is effectively no ice on the coil. This can be corrected by shifting the start of
the defrost proportionally to the lowering of the outside temperature.
This procedure can be performed based on the temperature or the pressure alone, and not combined. It is disabled
if the outside compensation probe is not fi tted or is broken. It is performed based on the pressure only if both the
pressure probe and temperature probe are confi gured.
- Start defrost temperature/pressure or condenser antifreeze
alarm set point
d03: For heat pumps with air-cooled condensers (H01=1, 3, 8, 10, 12), this sets the temperature or
pressure below which the defrost cycle starts. To start the defrost cycle, the condition must be valid for
the time d05. For water/water heat pumps with reversal on the gas circuit (H01=5, 10), it defi nes the set
point for the activation of the antifreeze alarm for the outdoor exchanger cooling water (evaporator in
heating mode, on probe B3).
If sliding is defrost enabled, the start defrost temperature decreases (starting from d03) proportionally to
the outside temperature.
- End defrost temperature/pressure
d04: Establishes the temperature or pressure above which the defrost cycle ends.
- Minimum start defrost time
d05: Establishes the time that temperature/pressure must remain below the start defrost threshold d03,
while the compressor is ON, for the defrost cycle to be activated.
Key:
1. end defrost T/P ;
2. start defrostT/P;
3. start defrostT;
4. end defrost;
5. min. time-interval to start a def. cycle (d6);
6. min defrost interval (d5);
7. timer reset.
- Minimum defrost duration
d06: Represents the minimum duration of the defrost cycle (the defrost continues even if the value read
by the condenser probe exceeds the end temperature/pressure). If set to 0, the minimum defrost time
function is disabled.
d06=0: control disabled.
- Maximum defrost duration
d07: If timed defrost is set (d02=0), this establishes the duration of the cycle.
If, on the other hand, the defrost ends at a set temperature/pressure, it represents the maximum duration
(being in this case a safety feature, an alarm is signalled, “dF1” or “dF2”).
- Delay between two defrost requests in the same circuit
d08: Represents the minimum delay between two successive defrost cycles.
- Defrost delay between the 2 circuits
d09: Represents the minimum delay between the defrost cycles on the 2 circuits.
- Defrost management from external contact
d10: This enables or disables defrost control from an external contact.
This function is typically used to end the defrost based on a signal from a thermostat/pressure switch
connected to the corresponding digital input. In this case, the defrost times are ignored.
d10 = 0: function disabled.
Note: for the other settings, the start and end defrost are enabled for temperature and pressure values
between the Defrost start and end set points
d10= 1: start defrost from external contact enabled therefore:
if the contact of the input is open, the start of the defrost is enabled;•
if the contact of the input closed, the defrost follows the normal procedure.•
Fig. 5.a.k
Defrost by temperature (d2= 1)