*CAUTION
: upon changing the display scale SCL, it is
ESSENTIAL
to reconfigure the parameters related to the absolute (SPL, SPH, SP, etc.)
and differential (HYS, ATL, ATH, etc.) temperatures.
4. THERMOSTAT CONTROL
4.1
Thermostat control is based on comparing the temperature T1, the set point
*SP
and the hysteresis
*HYS
, in the control mode
determined by parameter
C-H
. With C-H you choose refrigerating (REF) or heating (HEA) control mode. In order to understand control
modes better, please read the following example:
C-H=REF: with SP=2.0 and HYS=1.5, the compressor will be Off with T1= +2.0° and On with T1= +3.5° (2+1.5).
C-H=HEA: with SP=75 and HYS=3, the heater will be Off with T1= +75° and On with T1=72° (75-3).
The output only switches On again if the Off time period determined by
CRT
since the previous switchover has elapsed. Whenever a
very small hysteresis HYS must be maintained, it is advised that a suitable value for CRT is selected in order to reduce the number of
starts per hour.
4.2
If sensor T1 fails, the output is controlled by parameters
CT1
and
CT2
giving fixed On and Off times of the output.
Example: CT1=06, CT2=4, 6 minutes On, 4 minutes Off.
4.3
If door switch input control has been enabled (DS=YES), parameter
CSD
determines the delay between when the door is opened
and the compressor stopping.
* Actual setpoint and hysteresis depend on the selection
I/II
: in mode
I
, the reference parameters are
SP
and
HYS
while in mode
II
,
IISP
and
IIHY
.
5. DEFROSTING
5.1
Defrosting starts automatically when necessary time has elapsed to obtain the defrosting frequency set with
*DFR
. For example,
with DFR=4 defrosting occurs once every 6 hours. The internal timer is set to zero at the power-up and at each subsequent defrost start.
When the controller is put on a standby, the accumulated time count is “frozen” (is not incremented).
Defrosting may also be induced manually by keeping the button
pressed for 2 seconds.
With
C-H
=HEA, all defrost functions are inhibited; differently, with DFR=0, timed defrost only is removed.
5.2
Once defrost has started, the outputs are controlled according to parameter
DTY
as per the following table:
Table 3
5.3
Defrost lasts for the time
DTO
but, if the evaporator probe has been enabled (T2=YES) and temperature
DLI
is achieved before
this time elapses, defrost will be terminated in advance.
If parameter
DRN
is greater than 0, before cooling starts all outputs will remain off for the time assigned to DRN. This phase, called
drain down, will allow a complete ice melting and the drain of the resulting water.
* The actual defrost frequency depends on the selection
I/II
: in mode
I
, the reference parameter is
DFR
while in mode
II
it’s
IIDF
.
6. EVAPORATOR FANS
6.1
During termostatic control, the evaporator fans are controlled by parameters
*FTC
,
FT1
,
FT2
and
FT3
.
With FTC=YES an optimised fan control is enabled; in other words the fans will work in conjunction with the compressor (heater), and
after the compressor has stopped, the fans remain on for the time
FT1
(energy recovery), after that they will remain off for the time
FT2
(energy saving). After FT2, the fans will be on for the time
FT3
(whirling air stratifications).
Example: FT1=30, FT2=4, FT3=1. With those values the fans will cut-in together with the compressor and will stop 30 seconds after the
compressor has stopped; now, a 4 minute OFF and 1 minute ON cycle will take place till the compressor starts again.
With FT2=0 the fans will be on all the time; with FT2 greater than 0 and FT3=0 they will always be off.
With FTC=NO optimised fan control is excluded, therefore the fans will always be active.
6.2
If the MP1-15 is connected to a door switch and door switch control is enabled (DS=YES), during thermostatic control if the door
is opened, the fans will be stopped immediately.
6.3
During defrost, the fans are controlled by parameter
FID
; with FID=YES the fans remain on all through defrosting. With FID=NO,
INSTRUCTIONS FOR INSTALLATION AND USE.
DTY
D
EFROST
C
OMPRESSOR
OFF
Off
Off
ELE
On
Off
GAS
On
On
