Sub-Zero SZ-7524-P User Manual

Operation
When operating in the field of refrigeration, temperature control is
performed with a positive differential. The compressor stops when
the Setpoint temperature is reached and restarts when the
temperature reaches Setpoint plus the differential.
Two different defrost types can be selected : electrical the
compressor is stopped or at cycle inversion (Warm gas, the
compressor keeps working). It is also possible to select the interval
between defrosts (and the interval count type) and a maximum time
(time-out) after which defrost is interrupted. The same probe which
controls the defrost cycle is used to control the evaporator fans. It is
possible to set the temperature, the delay time after a defrost and
relation of fans with the compressor.
A series of “safety controls” (delay at start-up, minimum disable
time, minimum time between activation) protects the compressors
from close starts. In case of probe error or temperature alarm, the
instrument signals the event through acoustic signal and by closing
the relay contract. By pressing the mute key, the buzzer is silenced.
These functions can be easily customised by setting some
programming parameters. Other parameters allow to suit the
instrument to various applications.
1
value
Sr Parameter Parameter setting method
Min Max Fac
Set
1 Set point Function : To set the cutout
point of the controller.
Press and hold Display will change to set value
SET key for and LED will flash. The set point
2 second and value can now be changed by
release. using the UP/DOWN key. After
setting the desired value. Press
the SET key and you will see
“- - -” which confirms that the
set point has been stored in
memory.
To set other
parameter
Press & Hold Display will show P2 & will
DOWN(prg) flash. To go to other parameters,
key use UP/DOWN keys.
for 2 seconds.
2 P2 parameter Function: To set maximum
allowable high temperature limit.
P2 To change the Use UP/DOWN keys to set
P2 parameter, desired value. Once set at a
press the particular value, this will not allow
SET key. the set point to go above this
value and below P3 setting.
Example : Setting this parameter
0
at 25.0 C will not allow the set
0
point to go above 25.0 C. Also,
if the temperature reaches
0
25.0 C, the display will show Ht
SZ-7524-P
Introduction.
Features :
2 NTC probes for cold room temp. + Evap. coil temperature.
0 0
Range : -40.0 C to 50.0 C.
Relay outputs : Compressor + Defrost + Evap. Fan.
Compressor protection algoriithm.
Auto/Man defrosting facility (Time/Temp based).
Buzzer Output
R
0
50.0 C
XX
0
50.0 C
0
0.0 CP2 P3
XX = Set point
2
H
(Message on Display)

Sub-Zero SZ-7524-P Specifications

General

Brand	Sub-Zero
Model	SZ-7524-P
Category	Controller
Language	English