OSAKA – USER MANUAL – F 500 / F 500-RS – V.1 – Page 1
These options make it possible to control the starting of differing
defrosts for working days and non-working days to suit one's own
requirements.
For further detailed information and programming examples, see
the section on programmable events.
Note: Remember that for “Real Time Clock Defrosting” the user
must set “d.dC” = cL and the internal clock must be present and
enabled.
- Defrost by regular interval time
Counting mode interval and automatic defrost starts is set through
the parameter "d.dC" that can be programmed:
= rt - intervals with counts the total function time (instrument on)
This mode results that currently used in the refrigerators systems.
= ct - intervals with counts only the compressor function time
(output “ot” switched on)
Mode typically used in the positive temperature refrigerators system
with defrost by stopping compressor.
= cS - the instrument carries out a defrosting cycle at each
compressor stop (i.e. at each deactivation of the output “ot”) or
however at defrost interval end with counts the total function time
(instrument on).
If "d.di" = oF the defrost happens only to the compressor stop.
This mode is used only on particular refrigerator system in which is
desired to always have the evaporator to the maximum efficiency
conditions every compressor cycle.
The automatic defrost function is activate when at the parameter
“d.di” is set the defrost interval time.
The first defrost after swiching on can be set by par. “d.Sd”
This allows to perform the first defrost to a different interval from
"d.di." time.
If it is desired that to every instrument power on a defrost cycle is
realized (as long as the conditions set in the parameters “d.tS” and
"d.tE" apply) program the par. "d.Sd" = 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.
Instead if is desired all defrost to the same interval program "d.Sd"
= "d.di."
Automatic defrost function by interval is disable when “d.di” = oF.
“Dynamic Defrost Intervals System”.
If “d.dd” = 0 the Dynamic defrost is disable.
Note: For this function is necessary to use the evaporator probe,
program “d.dC” = rt, ct or cS and set “d.dd” = any value (not 0)
This mode allows to dynamically reduce in progress the defrost
interval counting ("d.di" or "d.Sd" if is the first defrost), anticipating
so the execution of a defrost when it was necessary, in order to an
algorithm that allows to notice a decrease performances of
refrigerator thermal exchange.
Besides it maintains activates the defrost by evaporator
temperature mode that it allows a further possibility of control of the
defrost in order to notice a decrease performances of refrigerator
thermal exchange.
The algorithm allows to esteem a reduction of thermal exchange in
base to the increase of the difference of temperature between Pr1
(controlled temperature) and evaporator (“EP” probe) that is
memorized by the instrument in proximity of the Set Point.
The advantage of the “Dynamic Defrost Interval” is the possibility to
program a defrost interval time more longer than normal.
The instrument will have the possibility to anticipate the defrost if
necessary or to start the cycle after the programmed time.
If the system results set correctly is possible to to avoid many non
necessary defrosting cycles (and therefore to obtain an energy
saving) that could instead happens in the normal operation when, to
guarantee with greater certainty the system efficency , the defrost
interval is programmed at a too low time.
Example “dynamic defrost intervals system” with a reduction “d.dd”
= 40 % and end defrost by temperature.
By par.: “d.dd” - DEFROST INTERVAL PERCENTAGE
REDUCTION is possible to establish the percentage of reduction of
the remaining time to start defrost when the conditions for the
reduction happen.
If par. "d.dd" = 100% at the first increase of the memorized
difference of temperature between cell (Pr1) and evaporator (> 1 °)
a defrost start immediately
For correct functioning the instrument needs a first reference value
of the temperature difference between cell and evaporator.
Every variation of the value of the Active Set Point, of the differential
"r.d", the start of a continuous cycle or the a defrost execution
delete this reference value and any reduction will be performed
until the acquisition of a new reference value.
- Defrost by evaporator temperature
The instrument starts a defrost cycle when the evaporator
temperature (“EP” probe) goes below the “d.tF” programmed
temperature for “d.St” programmed time.
This system can be used in heat pump defrost system (in this case
the defrosting intervals are usually disabled) or to guarantee a
defrost if the evaporator reaches very low temperatures that
normally result symptomatic of a bad thermal exchange in
comparison to the normal working conditions.
If “d.tF” = -99.9 the function is disable.
The function is active in all modes of defrost operation ("d.dC" = cL,
rt, ct, cS).
- Defrost by continuous compressor running time
The instrument start a defrost cycle when the compressor is turned
on continuously for the time "d.cd”.
This function is used because the continuous operation of the
compressor for an extended period is usually symptomatic of a bad
thermal exchange in comparison to the normal working conditions.
If "d.cd" = oF the function is disabled.
The function is active in all modes of defrost operation ("d.dC" = cL,
rt, ct, cS).
4.8.2- MANUAL DEFROST
To start up a manual defrosting cycle, press the key UP/DEFROST
when it is not in programming mode and keep it pressed for about 5
seconds after which, if the conditions are correct, the led Defrost will
light up and the instrument will carry out a defrosting cycle.
To stop a defrosting cycle, press the key UP/DEFROST during a
defrost cycle and keep it pressed for about 5 sec.
4.8.3 - DEFROST ENDS
With 1 evaporator
The automatic defrosting cycle can be ended by time or, if an
evaporator probe is used (“EP” probe), when a temperature on the
evaporator is reached.
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