STC-9100 Refrigeration Defrost Digital Thermostat with Alarm output

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China STC-9100 Compact Panel Defrost Thermostat - wholesale price, user manual, troubleshooting, wiring diagram, Setting guide video, and alternatives

The STC-9100 digital defrosts thermostat was designed to control the Refrigerating & Defrost & External Alarm power supply status through the 3 output relays and 2 NTC sensors. Typically suited to ultra-low temperature freezer room which easy to frost on its evaporator.

Minimum order Amount: 200 USD

STC-9100 Thermostat Features

Through the 3 output relays and 2 NTC sensors, the STC-9100 defrost thermostat owns the below features

  1. The temperature set-point ( -50 .0 to 50.0 ℃) and hysteresis to determine the target temperature range; And the High and low limit to the Temperature Set-point available;
  2. Control the refrigeration by temperature and editable delay time;
  3. Control the defrosting by temperature and editable delay time, and the artificial forced-defrost available;
  4. Supply an editable water dripping time;
  5. Defrost sensor temperature lasting showing on display is achievable;
  6. Alarm by error code on display and the buzzer screams, and the over-temperature alarm function can be disabled;
  7. Control the over-temperature alarm of the freezer room by time and temperature;
  8. Control the over-temperature alarm of the defrosting unit by time and temperature.
  9. Control the alarm output mode and range beside the buzzer alarm.

features 1 to 8 as same as the STC-9200

STC 9100 temperature controller Benefits

  • 3 alert modes available in the STC-9100 digital defrost thermostat;
  • both the room temp and the evaporator temperature could trigger alarming, and individual options for setting them;
  • Separately administrator and user menu, easy to operate for users, and the set-point range could be limited in the lockable admin menu;
  • Sufficient options for defrosting setting, like water dripping Time, defrosting lasting time, defrost interval time, Defrosting Stop Temperature, and the Count mode of defrost cycle
  • Batch upload/download configure data to the controller support by Copy-Key
  • Large and clear LED display with 0.1°C resolution;
  • 2 pieces waterproof NTC temperature sensor (2 m length sensor cable) with ±1°C accuracy;

Front Panel of STC-9100 Defrost Thermostat

Wiring Diagram of STC-9100 Defrost Controller

2020 New Wiring Diagram of Digital temperature controller STC 9100 from Haswill Electronics
2020 New Wiring Diagram of Digital temperature controller STC 9100 from Haswill Electronics
  • Port 1#: The live wiring from the input power will be output to loads from other ports (#2/3/4) if conditions are reached,  It’s dangerous if you connect the wrong wire.
  • port 2#: The relay for connecting the compressor to generate high-pressure hot air, it will make the evaporator temperature low down;
  • port 3#: The relay for wiring defrosting unit on the evaporator;
  • port 4#: The relay for alarm output, this unique design allows wiring an external alert which out of the walk-in freezer house;
  • port 5# & 6#: input power for STC-9100 working;
  • port 7#: The NTC Sensor for measuring the instant room temperature
  • Port 8: Co-point for dual temp NTC Sensor
  • port 9#: The NTC Sensor for measuring the instant temperature of the defrosting unit on the evaporator
  • Copy-key: Mini USB port suit to bulk configure controllers, different from the Ako temperature display controller, which use a master controller to manage slave units.

STC 9100 Temperature Controller Controll Refrigeration Defrosting wiring photo
STC 9100 Temperature Controller Control Refrigeration Defrosting wiring photo
Old Wiring Diagram of Digital temperature controller STC 9100
Old Wiring Diagram of Digital temperature controller STC 9100


Function Menu of STC 9100 Defrost Controller

The EN code and F code version are both available.

Cate.EN CodeF CodeFunctionMinMaxDefaultUnitMenu Level
Temp.SETF01SP (Temperature Set-Point)LSUS-5°CUser Menu
HYF02Temperature Hysteresis / Return Difference1252°C
USF03Upper limit for SPSET5020°CAdmin Menu
LSF04Lower limit for SP-50SET-20°C
ACF05Delay Time for Compressor
Delay time for defrosting (only for thermal air mode)
Defr.IDFF06DefrostCycle / Interval Time01206Hour
MDFF07Lasting Time025530Min
DTEF08Stop Temperature-505010°C
FDTF09Water dripping Time01002Min
TDFF10Defrosting Mode:
EL: defrost by electrical-heating;
HTG: defrost by thermal air
DCTF11Count mode of defrost cycle:
RT: Cumulative time from controller power on;
COH: Cumulative time of the compressor working.
DFDF12Display mode when defrosting:
RT: Shows the Room sensor temperature;
IT: Shows the evaporator sensor temperature ( lasting
10 min after defrosting over)
AlarmDMOF13Alarm output options:
N-C: N/A, banned;
A-C: follow the buzzer, press any key to stops;
A-A: follow the buzzer, keep screaming unless fixed all errors.
ELLF14Evaporator Sensor Temperature to Trigger AlarmLower Limit-50ELU-50°C
EODF15Time delay02550Min
ELUF16Upper LimitELL5050°C
ALUF17Room sensor Temperature to Trigger AlarmUpper LimitALL5050°C
ALLF18Lower Limit-50ALU-50°C
ALDF19Time delay09915Min
Calib.OTF20Temperature Calibration-10100°C

How to set the temperature?

The room temperature was defined from "F1" to "F1 + F2" (from "SET" to "SET + HY");

You can set them in the user interface or the Admin Interface, below is the method for the administrator.

  1. Enter the Admin Interface: hold the [SET] key and the [Down] key at the same time for 10s; you will see the code "F1" ("SET").
  2. Press the [SET] key to check the current value, and press the [Down] key or the [Up] key to change the F1 value;
  3. Press the [SET] key to save the new data, and back to the menu list, you will see the code "F1" ("SET") again.
  4. Switch to the "F2" ("HY") code by pressing [UP] the key.

Please reference section 4.1 in the PDF instruction for the "setting method in user interface".

How to Configure the Defrosting

This unit controls the defrosting by Time and Temperature.

  1. Temperature Condition: the evaporation sensor temperature is lower than the preset "defrosting Stop temperature" F8 (DTE), which is a significant value to prevent over defrost.
  2. Time Condition 1: the real-time passes the preset interval time F6 (IDF), a regular parameter for almost all defrosting thermostats.
  3. Time Condition 2: If the "defrosting method" you take is the hot gas from the compressor reverse rotary when F10 = 1 (TDF= HTG), it will count the compressor's last stops moment plus F5 (AC), which is a protective value to avoid the compressor frequently startup and stops.

How to set the External Alarm? Unlike other defrost thermostats, which only reference the room sensor, this unit STC-9100 also monitors the evaporator sensor.

  1. Check the Alarm output options in F13 (DMO);
  2. And then check below items F14 – F19

STC-9100 Thermostat Error Code and Trouble-Shoot

Once alarming, the readout flashing and buzzer screaming, you can press any key to stop the buzzer ticktack, but the error code in the display will not disappear until all errors have been fixed.

  • The below codes means error from the Room thermistor: E01, E03, RH, RL;
  • The below codes means error from the defrost thermistor:  E02, E04, EH, EL.
Most errors could be solved by replacing a new sensor, please find more solutions from the below user manual.

User Manual of STC9100 Defrost Thermostat

Please be aware that the English page only displays the English version of the user manual, please switch to the corresponding language page to download the PDF manual in other languages.

Tip: This User instruction was created based on the Elitech STC-9100 Defrost Alarm thermostat, we can not assure you this brochure also works to the same models from other manufacturers.


FAQ of Haswill Compact Panel Thermostat

  1. How to avoid buying Inferior temperature controllers?
    here is a simple method, that does not require professional knowledge.
  2. How to get the price?
    Click the inquiry button, and finish the form, You will get a reply in a few hours.
  3. Celsius VS Fahrenheit; and Voltage
    All of our digital temperature controllers default in Celsius degrees, and part of them is available in Fahrenheit with different minimum order quantities;
    Besides the 220V AC (±15%), these electronic temperature controllers also are available in 110V AC, 12V DC, and 24V DC (110 / 24 /12 Volts ).
  4. Parameter Comparison
    Catalog of Compact panel digital temperature controllers
  5. Package
    The standard package could load 100 PCS / CTN digital temperature controllers.
  6. Accessories
    We suggest you buy 5% ~ 10% spare parts like clips and sensors as stock.
  7. Warranty
    Default one-year (extendable) quality warranty to all our controllers, We will offer a free-of-charge replacement if found a quality defect.
  8. Customization Service
    If you can not find a suitable temperature controller on this website, We will help you develop it based on our existing mature products ;
    Thanks to China's complete set of related industry chains, our customized thermostats are of high quality and low price;
    the MOQ is usually from 1000 pieces. don't hesitate to contact us for customization services.

or more questions? Click FAQs

Minimum order Amount: 200 USD


Regarding the voltage of this electronic temperature controller

  • 220V AC (±15%) as the default, Without MOQ (minimum order quantity) requirement;
  • 110V AC (±15%) with MOQ 200 PCS;
  • 12V DC with MOQ 200 PCS;
  • 24V DC Without MOQ requirement;

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