Ascon Tecnologic - e34B - OPERATING INSTRUCTIONS - PAG. 10
times of the ot output (ot output activated). This mode
is usually used in refrigeration systems with compres-
sor stop defrosting.
cS Defrost cycle at each compressor stop. The instrument
starts a defrost cycle every time the ot output is deac-
tivated, when the Set Point is reached or at the expira-
tion of the interval set with ddi paramreter. If ddi =
oF the defrost happens only at compressor stop.
This mode is used only on particular refrigerating ma-
chines in which is required the maximum evaporator
efficiency at each compressor cycle.
To enable automatic defrost at intervals, after setting the ddC
parameter as desired between rt, ct or cS, with the ddi pa-
rameter select the time interval between the end of a defrost
and the beginning of the next.
The time that the instrument must wait to perform the first
defrost after power ON can be set with parameter dSd. This
allows to perform the first defrost to a different interval from
ddi time.
To force the instrument to perform a defrost cycle at each
power ON (as long as the conditions set with parameters
dtS and dtE are satisfied) set parameter dSd = oF.
This allows the evaporator to be permanently defrosted,
even when frequent interruptions to power supply occur that
may cause the cancellation of the various defrosting cycles.
If instead it is desired that all the defrosts are performed at
the same interval time, set dSd = ddi.
Setting ddi = oF the Automatic defrost function by interval
is totally disabled (including the first, regardless of the time
set to the dsd parameter).
Dynamic Defrost Intervals System
Note: For this function is necessary to use the evaporator
probe.
To enable the Dynamic Defrost Intervals System, program
ddC = rt, ct or cS and set ddd = any value.
Setting ddd = 0, the defrost intervals are those set by the user
and the Dynamic Defrost Intervals System is disabled.
This mode allows to dynamically reduce the defrost interval
counting (ddi or dSd if is the first defrost), anticipating, when
necessary, the defrost execution, all based on an algorithm that
detects a drop in the refrigerator thermal exchange performance.
The algorithm estimates a reduction in thermal exchange
based on the increase in temperature difference between
Pr1 (cell control) and evaporator probe (probe configured as
EP). The result is stored by the instrument when the tem-
perature is close to the Set Point setting.
The advantage of the Dynamic Defrost Interval is the pos-
sibility to program a defrost interval time longer than normal,
so, when necessary, the instrument has the possibility to
anticipate the defrost.
If the system results correctly set, it is possible to avoid
many unnecessary defrosting cycles (and therefore to obtain
aconsistent energy saving) that may occur with normal op-
eration when, to ensure more system efficiency, the defrost-
ing interval is programmed with a time that is often too short.
With the parameter ddd - Defrost interval percentage reduc-
tion is possible to establish the percentage of reduction of
the remaining time to start defrost when the conditions for
the reduction happen.
Setting ddd = 100% at the first increase of the stored tem-
perature difference (> 1°) between cell (Pr1) and evaporator
(EP) probes a defrost starts immediately.
For correct functioning the instrument needs a first refer-
ence value of the temperature difference between cell and
evaporator, in this way all variations to the Active Set Point
value, to the differential rd, the start of a continuous cycle
or a defrost execution deletes this reference value and any
reduction cannot be performed until the acquisition of a new
reference value.
Phase
off off
ON
01 2 3
Temp.
ddi/dSd time to defrost Phases 0, 1
Defrost
off off
DT0
dtE
dtS
Cool
ot
Defrost
dF
SP + rd
SP
Pr1
rd
EP
1°
DT1 DT2 DT3
time to defrost Phase 2
time to defrost Phase 3
time
ON ON ON
Example “dynamic defrost intervals system” with a reduction
ddd = 40% and end defrost by temperature.
Defrost by evaporator temperature
The instrument starts a defrost cycle when the evaporator
temperature (EP probe) goes below the dtF programmed
temperature for dSt programmed time.
This modality can be used to guarantee a defrost if the
evaporator reaches very low temperatures that normally re-
sult symptomatic of a bad thermal exchange in comparison
to the normal working conditions.
When dtF = -99.9 the function is disabled.
Defrost by continuous compressor running time
The instrument start a defrost cycle when the compressor is
turned ON continuously for the time dcd.
This function is used because the continuous operation for an
extended period of the compressor is usually symptomatic of
a bad thermal exchange in comparison to the normal work-
ing conditions.
When dcd = oF the function is disabled.
5.8.2 Manual defrost
To start a manual defrost cycle, press the key / when
in Normal operation mode and keep it pressed for about 5 s
after which, if the conditions are correct, the LED lights up
and the instrument performs a defrost cycle.
To stop a defrost cycle, press the key / during the de-
frost and keep it pressed for about 5 seconds.
5.8.3 End of defrosts
The defrost cycle duration can be time based, or, using the
evaporator probe (configured as EP) when a specific tem-
perature is reached.
If the evaporator probe is not used, the cycle time is set
by parameter ddE (setting ddE = oF the Time-interval or
Manual defrosts are disabled).
If, on the other hand, the evaporator probe is used, the end
of defrosting occurs when the temperature measured by this
probe configured as EP exceeds the temperature set with
parameter dtE. If dtE temperature is not reached within the
time set at parameter ddE, the defrost is anyway interrupted.
To avoid unnecessary defrosting when the evaporator tem-
To Next Page
Loading...
Need help?
General
