Ascon Tecnologic - e34B - OPERATING INSTRUCTIONS - PAG. 11
perature is high, parameter
DtS
allows to set the temperature
related to the
EP
probe under which defrosts are possible.
Therefore, in the indicated modes, if the temperature meas-
ured by the
EP
probe is higher than the one set at parameter
dtS
and also
dtE
defrosts are inhibited.
dtE
dts
Defrost
dF
off
off
off
ON
ON
A
B
Temp.
time
C
(NO defrost)
dde
ddi/dSd
(Defrost)
ddi/dSd
ddi/dSd
ddi
(Defrost)
EP
Example: Defrost
A
ends due to reaching of temperature
dtE
, defrost
B
ends at the end of the
ddE
time as the
temperature
dtE
is not reached, defrosting
C
does not take
place as the temperature is higher than
dts
.
dtE
dts
off
off
off
off
ddi/dSd
ON
ON
ON
time
ddi
(Defrost)
dde
1°
Defrost
dF
Temp.
EP
Example of electric defrost with evaporator temperature
control: the defrost end after
ddE
programmed time. During
defrost the
dF
output switch ON/OFF to control evaporator
temperature in heating mode with set point
dtE
and 1° dif-
ferential (Hysteresis).
The active defrost is shown on the instrument display with
the lighting up of the LED .
At the end of defrosting, it is possible to delay the new com-
pressor start up (output
ot
) at the time set in parameter
dtd
to allow the evaporator to drain. During this delay, the LED
flashes to indicate the draining state.
5.8.4
Intervals and defrosts duration in case of
evaporator probe error
In event of evaporator probe error the defrosts occur at inter-
vals
dEi
and duration
dEE
.
In case an error occurs when the time remaining to the start
or the end of defrost is lower than the one normally set with
the parameters related to error probe conditions, the start or
the end takes place with the shortest time.
These functions are provided because when the
EP
evapo-
rator probe is used, the set defrost endurance time is usually
longer than necessary (the time
ddE
is a security time-out)
and in case is used the “Dynamic Intervals Defrost System”
the interval is usually set more longer than what is normally
programmed into instruments that do not have the function.
5.8.5
Display lock during Defrost
Through parameters
ddL
and
AdA
it is possible to define the
display behaviour during defrost:
on
The
ddL
parameter locks the display at the last
Pr1
temperature reading during all the defrost cycle until,
at the end of defrost, the temperature has not reached
the lock value or the value [
SP
+
rd
] or is elapsed the
time set at parameter
AdA
;
oF
The display continues showing the temperature meas-
ured by the
Pr1
probe during the defrost cycle.
5.9
Evaporator fans control
The control of the evaporator fans on the output configured as
Fn
depends on some specific control statuses of the instrument
and the temperature measured by the evaporator probe (
EP
).
In the case that the evaporator probe is not used or in error,
the
Fn
output is activated only depending on parameters
Ftn
,
FtF
and
FFE
.
Parameters
Ftn
and
FtF
can be used to determine the behavior
of the evaporator fans when the
ot
outupt (compressor) is
OFF
.
When
ot
output is
OFF
, it is possible to set the instrument so
that that the
Fn
output continues working in cycles according
to the times programmed at parameters
Ftn
(fan activation
time) and
FtF
(fan deactivation time).
When output
ot
is switched
OFF
the instrument activates the
output
Fn
for the time
Ftn
, then deactivates it for the time
FtF
and so on whilst the otuput
ot
remains
OFF
.
Programming
Ftn
=
oF
the output
Fn
in
ot
OFF
condition
remains switched
OFF
.
Programming instead
Ftn
to any value and
FtF
=
oF
the
output
Fn
when
ot
in
OFF
condition remains switched
ON
.
The parameter
FFE
decides whether the fans must always
be switched
ON
independently of the defrosting status
(
FFE
=
on
) or switched
OFF
during defrosting (
FFE
=
oF
).
In this later case, it is possible to delay the start up of the
fans even after the end of the defrost by the time set at
FFd
parameter. When this delay is active the LED flashes to
point out that the
FFd
delay is in progress.
When the evaporator probe is used the fans, as well as be-
ing conditioned by the parameters
Ftn
,
FtF
and
FFE
, are
also conditioned by a temperature control.
FLF
FFL
Temp.
FdF
FdF
time
off
off
off
ON
ON
Ep
Fan
Note:
It is necessary to pay attention to the correct use of
this fans temperature control functions because in
the typical application of refrigeration the stop of the
evaporator fans stops also the thermal exchange.
Remember that the fans functioning can be conditioned by
the
Door open
function by the digital input.
