TM

Suggested Wiring SZ-7520T (230Vac) USER INTERFACE 3 P2 Parameter Function: To set maximum allowable high
SZ-7520T / SZ-7529T temperature limit.
230VAC UP In Program mode:
COMP
Operating Instructions PROBE 50-60Hz
NC NO C
Scroll through parameters & Increases To change value use keys To set value touch "SET" key
parameter value.
1 2 3 5 6 7 8
In Set mode : Increases parameter value. Example: If this parameter is set to 50OC and the temperature
reaches or goes above 50OC, display will show Ht (High Temp.)
PRG Down/ Touch and hold for 2sec to enter into program indicating that the temperature has reached or gone above the

To Compressor
Program mode.

8(3)A 250VAC
value set in this parameter.
In program mode and set mode:

max
TO SZ-T75
Decreases parameter value Min Max Fac.

(Message on display) P3+1 99OC 99OC

PHASE Defrost Touch & hold for 2 sec to start a manual
defrost and to stop Auto / Manual defrost 4 P3 Parameter Function: To set minimum allowable low
NEUTRAL
cycle. temperature limit.
Caution:Wiring for 230Vac load only
Touch Sensitive Temperature Controller Example: If this parameter is set to -10OC and the temperature
Also used to Exit from program mode.
Suggested Wiring SZ-7529T (230Vac) reaches or goes below -10OC, display will show Lt (Low temp)
Introduction : indicating that the temperature has reached or gone below the
The new SZ-7520T/7529T are the next generation of Subzero SET Set Touch and hold for 2sec to enter into set mode.
230VAC value set in this parameter.
controllers. Their IP ratings are greatly improved and have an excellent 50-60Hz In program mode and set mode:
iconic display. The touch feature whilst increasing reliability also gives a PROBE COMPRESSOR set/save the changed value of parameter. Min Max Fac.
great user experience. 1 2 3 5 C NO O O
(Message on display) -40 C P2-1 -40 C
These controllers designed for refrigeration have several features INDEX
specially designed for safety of compressors. They work on the system
5 HS Parameter Function: To set Maximum set point limit.
Sr. Description
Para.

To Compressor
20A(8)250VAC
that the compressor cuts off at set point and is restarted at a temperature No.
of set point + differential. Once set at a particular value, this will not allow the set point to

max
TO SZ-T75 1 Set Point Compressor relay set point. go above this value.
Their operation is very user friendly and is easily understood with the 2 Set other parameter.
examples in the instructions below.
Example: Setting this parameter at 25°C will not allow the set
PHASE 3 P2 High temperature limit. point to go above 24°C (HS-1). Min Max Fac.
Various parameters help set up the instruments functions for different NEUTRAL 4 P3 Low temperature limit. O O
applications. SP+1 99 C 99 C
5 HS Maximum Set Point limit. SP = Set Point
Caution:Wiring for 230Vac load only
The SZ-7520T/7529T is specifically designed for defrost applications 6 LS Parameter Function: To set Minimum set point limit.
6 LS Minimum Set Point limit.
with a measuring range from -45OC to 99OC. Suggested Wiring SZ-7520T 7 P4 Differential for compressor relay ON condition. Once set at a particular value, this will not allow the set point to
CAUTION 8 P5 Probe calibration. go below this value.
POWER COMP
WIRING: The probe and its corresponding wires should never be PROBE SUPPLY NC NO C 9 P6 Time delay (compressor relay restart after cutoff). Example: Setting this parameter at -10°C will not allow the
installed in a conduit next to control or power supply lines. The electrical
Minimum ON time for compressor relay.
set point to go below -9°C (LS+1).
wiring should be done as shown in the diagram. The power supply circuit 1 2 3 5 6 7 8 10 Ot Min Max Fac.
should be connected to a protection switch. The terminals admit wires of 11 E1 Compressor relay status in probe fail. -40OC SP-1 -40OC
upto 2.5sq mm. SP = Set Point
12 Cn Compressor relay OFF time during probe fault.

To Compressor
7 P4 Parameter Function: To set the differential for

8(3)A 250VAC
WARNING: Improper wiring may cause irreparable damage and 13 Cy Compressor relay ON time during probe fault. compressor relay ON condition.

max
personal injury. Kindly ensure that wiring is done by qualified personnel TO SZ-T75
14 P7 Duration for Defrost Cycle.
only. Example : If the set point is set at 10OC and differential is set at
15 P8 Frequency for Defrost Cycle. 2OC, then when the system reaches 10OC, the compressor
Maintenance: Cleaning: Clean the surface of the controller with a soft PHASE
moist cloth. Do not use abrasive detergents, petrol, alcohol or solvents. 16 dF Display while the Defrost Cycle is in progress. relay will go OFF. Since the differential is 2OC, the compressor
NEUTRAL
Notice: The information in this document is subject to change in order to 17 dd Delay the display of temperature. relay will come ON (restart) at 12OC (10OC +2OC).
improve reliability , design or function without prior notice and does not 12Vac/dc or 24Vac/dc or 48Vdc
represent a commitment on the part of the company. In no event will the 18 Ad Time delay at Power ON for alarm indication. Min Max Fac.
company be liable for direct, indirect, special, incidental or consequential 19 PA Change Password
damage arising out of the use or inability to use the product or
Suggested Wiring SZ-7529T 1OC 20OC 2OC
documentation, even if advised of the possibility of such damages. No 20 LP Keypad Lock
8 P5 Parameter Function: To set probe calibration.
part of this manual may be reproduced or transmitted in any form or by 21 FS Restore factory defaults
POWER
any means without the prior written permission of the company. PROBE SUPPLY COMPRESSOR In time it may be possible that the display may be offset by a
22 EP End Programming
Installation : Fixing and dimensions of panel models: 1 2 3 5 degree or so.
To fix the unit, slide the fastener 1 through the guides 2 as per the
C NO 23 LED Indications
To compensate for this error, user may need to add or minus
position shown in the figure. Move the fastener in the direction of the Operating Messages (Normal Mode) the degrees required to achieve the correct temperature.
arrow, pressing tab 3 it permits to move the fastener in the opposite
Operating Messages (Pro-key Mode) Example : The temperature on the display is 28OC, whereas
To Compressor

direction of the arrow.

20A(8)250VAC

Password Function the actual temperature is 30OC. User will have to set the P5
max

Controller :Controller should be installed in a place protected by TO SZ-T75 parameter to 2, which means that once out of the programming
vibration, water and corrosive gasses and where ambient temperature
Temperature Logging
does not exceed the values specified in the technical data. User Selectable Default Values mode, the temperature on display will be 30OC (28OC+ 2OC).
PHASE
Min Max Fac.
Probe :To give a correct reading, the probe must be installed in a place NEUTRAL Parameter List :
protected from thermal influences, which may affect the temperature to O
-10 C
O
10 C
O
0C
be controlled. 12Vac/dc or 24Vac/dc or 48Vdc or 110Vac 1 Set point Function: To set compressor relay set point. 9 P6 Parameter Function: To set time delay between
Panel Cutout and Dimensions : TECHNICAL DATA SET compressor relay restart.
MAX
10mm Touch & hold key for 2 seconds. This parameter is used to protect the compressor from
2 1 Housing : Black ABS Plastic, Auto-extinguish
3
Front Cover : Polycarbonate Plastic restarting in a short period of time.
Dimensions : Frontal : 78 X 36mm, Depth : 59mm Display will show set value. The set point value can now be Example: If this parameter is set at 3 minutes, the compressor
Panel cutout

71mm

Panel Cutout : 29 X 71mm modified by using the UP/DOWN key. After selecting the desired relay goes OFF at the set point, it will not restart for a minimum
36mm Mounting : Flush panel mounting with fasteners value, touch the set key and user can see "- -" which confirms that of 3 minutes, even if the differential is achieved earlier. This
Protection : IP65 Front (with gasket) the set point has been stored in memory. parameter is good to protect the life of the compressor.
Connections : Screw terminal blocks.
< 2.5sq mm terminal only. Min Max Fac. Min Max Fac.
59 mm Display : 2 X 17mm 7 segment display & O Flashing 0 Min 99 Min 3 Min
LS+1 HS-1 0C
29mm Time delay in progress
5 LEDs for Indication
Side Lock
Data storage : Non-volatile EEPROM memory 2 To set other 10 Ot Parameter Function: Minimum ON Time For
PANEL Display will flash “P2”.
Power input : 230 Vac ±15 % , 50-60Hz. Parameters. To select other parameters, use UP/DOWN Compressor relay.
Others on request. Touch & hold keys. This parameter is used to protect the compressor so that there
GASKET Relay output : Comp SPST relay 20(8)A,250V AC (for SZ-7529T) is enough time for oil to return back to the compressor. This
Comp SPDT relay 8(3)A,250V AC (for SZ-7520T) delay starts once the compressor relay is ON.
Operating temp. : 0°C to 60°C (non-condensing)
Operating humidity : 20% to 85% (non-condensing)
Example: If this parameter is set at 1Min and if the
key for temperature is achieved before 1 minute, then the compressor
Storage temp : -25°C to 60°C (non-condensing) 2 seconds.
Measuring Range : -45°C to 99°C
relay will remain ON for minimum 1 minute, though set point is
Input : NTC probe, SZ-T75
achieved.
Min Max Fac.
Resolution : +/- 1°C
Accuracy : +/- 1°C 0 Min 20 Min 0 Min
CONTROLLER
11 E1 Parameter Function : Compressor relay status in case 18 Ad Parameter Function : This parameter is used to set the OPERATING MESSAGES (Normal Mode) User selectable Default values
of Probe Failure. time delay at Power ON for Alarm Indication.
User can set their own set of Default Set values for all parameters. If
When set to
Ht High temperature alarm Lt Low temperature alarm
user wants to activate this feature, Program mode must be
Example: If this parameter is set to 20 minutes, once the Temperature above the Temperature below the
0 = Compressor relay status is OFF. controller is powered ON, no fault indication will be activated for accessed and then change Factory set (FS) parameter
maximum high minimum low
1 = Compressor relay status is ON. 20 minutes. accordingly.
temperature limit. temperature limit.
2 = Compressor relay performs a duty cycle for Cn for
minutes OFF and Cy for minutes ON. Alarm delay is used only for High Temperature and Low PP Probe fail LP Keypad lock This can be done by following steps:
Temperature, but not for Room Sensor fail. Probe short circuit, circuit Keypad is locked
Min Max Fac. open or without probe, or
If Control Probe Temperature reaches or goes above P2 temperature is > 990C or Modify values of set point and other parameters as desired by
0 2 2 parameter value, High Temperature (Ht) fault will displayed. entering set mode and program mode respectively.
<-400C
12 Cn Parameter Function : Compressor relay OFF Time Select FS parameter and touch "SET" key. While display
during probe fault.
If Control Probe Temperature reaches or drops below P3 LL Last low temperature LH Last high temperature
flashing “0” , touch and hold " " for 10sec. Controller will flash
parameter value, Low Temperature (Lt) fault will displayed. Last low temperature Last high temperature
logged. logged. "-2". Then touch "SET" key. All the user defined parameter
(This will be considered only when E1 is selected 2 ) . Differential of 1OC is considered for clearing the fault. values will be stored as ‘User Default set’.
Example : If this parameter is set to 4 minutes, then Min Max Fac. rS In log function: When LL dF Defrost If user wants to use this set of parameters, access Program
and LH values are cleared. Defrost in progress. mode and set the FS parameter to "2". Controller will restore the
compressor relay will be OFF for 4 minutes while performing ON
0 Min 99 Min 0 Min user defined parameter values.
the duty cycle. Fault is present
Min Max Fac. 19 PA Parameter Function : To change Password. OPERATING MESSAGES (Pro-key Mode)
(Note: Keypad parameter LP and User lock parameter will be
1 Min 99 Min 4 Min
Pr Shows controller in Pro- uP Shows selection of taken into consideration while modifying this parameter.)
13 Cy Parameter Function : Compressor relay ON Time User cannot enter into program mode & set mode, if correct key mode. uploading mode, parameter
during probe fault. password is not entered. values can be uploaded Disclaimer: This manual & its contents remain the sole property of
from controller to pro key. PVR CONTROLS . India and shall not be reproduced or
(This will be considered only when E1 is selected 2 ) . If the password is kept other then 0, user need to enter correct dn Shows selection of down En Shows the Pro-key is distributed without authorization. Although great care has been
Example : If this parameter is set to 10 minutes, then password to enter into set/program mode. loading mode, parameter validated by controller. taken in the preparation of this document, the company or its
compressor relay will be ON for 10 minutes while performing values can be down loaded vendors in no event will be liable for direct, indirect, special,
the duty cycle. If password is 0, user can directly access set/program mode. from pro key to controller. incidental or consequential damage arising out of the use or
Min Max Fac. inability to use the product or documentation, even if advised of the
Min Max Fac. Er Shows an error in Pro- CL User lock is active. possibility of such damages. No part of this manual may be
1 Min 99 Min 10 Min key validation / error in
-99 99 0 reproduced or transmitted in any form or by any means without the
uploading or down loading
14 P7 Parameter Function : This Parameter is used to set the prior written permission of the company. PVR CONTROLS.,
20 LP Parameter Function: To lock keypad. parameters/error in setting
Duration for Defrost Cycle. user lock function. reserves the right to make and changes or improvements without
prior notice.
This paramter is applicable for both Auto and Manal Defrost This parameter is used to lock the keypad so that tampering is UL User lock is not active. Warranty: This product is warranted against defects in materials
and specifies for how much time the Defrost will last. not possible by by-standers.
Password function and workmanship for a period of one year from the date of
Example : If this parameter is set to 30 Minutes and Defrost 0 = keypad unlocked purchase. During the warranty period, product determined by us to
Frequency means P8 parameter is set to 1 Hour, then 1 Hour 1 = keypad locked In Program mode:
be defective in form or function will be repaired or, at our option,
after Power is applied to the controller, defrost will take place When locked all parameters can only be viewed, but not Touch & hold " " key for 2sec. Display will flash "P2"
replaced at no charge. This warranty does not apply if the product
for 30 minutes. This Cycle will repeat after every 1 Hour. modified. parameter if "PA" value is kept "0". If other than "0", then "PA'
has been damaged by accident, abuse, and misuse or as a result of
Min Max Fac. and "0" will flash. Use " "and " " keys to enter the service or modification other than by the company. This warranty is
ON Note : If LP parameter is set to 1 and if user tries to change any password. On entering correct value, display will flash the first in lieu of any other warranty expressed or implied. In no event shall
Defrost in Progress 0 Min 99 Min 30 Min parameter value, " LP" will flash on the display. parameter "P2". User can scroll through parameters using the company be held liable for incidental or consequential
15 P8 Parameter Function : This Parameter is used to set the Min Max Fac. " " or " " keys. damages, including lost revenue or lost business opportunity
frequency for Defrost Cycle. In Set mode:
Flashing 0 1 0 arising from the purchase of this product.
This parameter is applicable only for Auto Defrost. Touch & hold "SET" key for 2sec. Display will flash set point
21 FS Parameter Function : To restore default settings of the
Example : As explained for P7 parameter. value if “PA” parameter value is kept to “0”. If other than “0”, OUR OTHER PRODUCTS
controller.
then display will flash “PA” and “0”. Use " " or " " to enter TM

Min Max Fac. When set to 1 all parameters are programmed to factory set the password. On entering correct value, display will flash set R

values.
1 Hr 31 Hr 6 Hr point value. User can set desired value using " "or " "
Useful to debug setting related Problems.
16 dF Parameter Function : This parameter is used to select keys. To save the modified value use "SET" key.
When set to, Cold Room Controller
display while the Defrost Cycle is in High and Low temperature logging function Ball Valves
progress. 0 = FS is disable. Chiller Controller Globe Valves
1 = FS as per default value. How to see the logged values: Two Compressor Controller Hand Valves
Min Max Fac.
Example : When this parameter is set to, 2 = FS as per user define Heating Controller Flow Switches
LL : Last Low temperature
0 2 0 Humidity Controller Solenoid Valves
0: While the Defrost is ON , Control Probe temperature will be LH : Last High temperature Pressure Controller
displayed. 22 EP Parameter Function: To end programming. Touch and hold " " key for 1sec. display will flash “LL” and
03 / 09.10.18
the corresponding temperature for 4 seconds. After this,
1: While the Defrost is ON, "dF" will be displayed. To end Once the key is pressed, the controller goes
programming display will flash “LH” and the corresponding temperature for
into the normal mode and displays the
Min Max Fac. press "SET" key temperature and all settings are recorded. 4 seconds and come out of Log mode and will display
Control probe temperature.
0 1 0
LEDS How to reset the Logged values
17 dd Parameter Function : This parameter is used to delay While the display is showing the logged values, if user
the display of temperature by the set in Compressor Alarm touches & holds the "SET" key for 1sec, the logged values will
this parameter. ON: Compressor is ON. ON: Alarm relay ON. be cleared and "rS" will be displayed.
Each value corresponds to 5 seconds, if the value is set to 1, it OFF: Compressor is OFF. OFF: Alarm relay OFF.
Log Values will get reset after Power ON/OFF.
corresponds to 5 seconds, if it is set to 2, it corresponds to 10
Time Delay Defrost
seconds and so on.
ON: Compressor is ON ON: Defrost in progress.
For example, if this parameter is set to 1, temperature on the and in time delay
display will be updated after 5 seconds. The same value will be for switching OFF.
considered for calculation and logging. (Ot parameter)
Display delay parameter is applicable only when temperature FLASHING:
Compressor is in
is increasing (rising). When temperature is decreasing (falling)
time delay and
this parameter will not be applicable. about to start.
If this parameter is set to 0, this feature will be disabled.
ON: When temperature is displayed.
Min Max Fac.
0 36 0