Generator room cooling automation project (STC -1000 Thermostat)

STC — 1000 Thermostat
STC — 1000 Thermostat (Displaying the current temperature of the room)

I got this device to use for my generator room cooling system. It’s an enclosed room to reduce the noise and there are two exhaust fans working in unison, one pushing air into the room and one pushing air out of the room. After the genset has been running for a while, even if the genset is off, the heat of the room is there. And it takes a long time for the heated air to get out of the room.

Due to this reason, I wanted to leave the exhaust fans on till the heat came down to a certain level and I wanted to automate the process. That’s where this device (thermostat) comes in.

Technical Stuff (C = Celsius)

  1. Blinking dot on the top left lets us know that the thermostat is not yet operational.

(Once it stopped blinking, then that indicates that it’s operational. It’s an added feature for protection. If you use this thermostat in an environment where you get sudden power outages and the power comes back in, this acts as a delay. If this feature was not available, this device will turn on and off the connected device rapidly as the power comes on and goes. That is clearly not good for electrical appliances. Specially refrigerators and such)

2. Once the thermostat is on, it will show you the temperature of the place where the probe is.

(There is a metal part with a wire at the end. That is the temperature probe, If you touch it with a warm hand, you can see the heat goes up in the LED display. See the picture below.)

Temparature probe (sensor) of the STC — 1000
Temperature Probe (Sensor) of STC — 1000 Thermostat

4. If you press the DOWN ARROW, it shows you what the differential value is.

If you set it to “1C” degree and your thermoset will start heating at “34C” degrees (That is if you have set the thermostat to start at “35C”). And cooling will start to kick in at “36C”. (That is also if you had the thermostat setup at “35C”, the difference is set at “1C”)

You can set it to “0”, if you don’t want any delay.

You have TWO outputs coming out of the thermostat (Refer to the diagram below, before wiring)

Wiring diagram of STC — 1000 Thermostat
Wiring diagram of STC — 1000 Thermostat

1. One for the cooling device (Ex — Exhaust Fan, Freezer)
2. One for the Heating device (Ex — Heater)

For my project, I will only be using the cooling side of the circuit, because I don’t need to heat the room. Your purpose can and will be different from mine, so wire it accordingly. (Each output can handle up to 10A of current)

Industrial Exhaust Fans used in my generator room cooling system project
Industrial Exhaust Fans used in my generator room cooling system project. This one pushes air into the room and there is one inside pushing air out of the room. Can also be configured to pull air out of the room. Exhaust fan blade size, Wattage, RPM will depend on the size of the room your generator is in. Refer to your Genset manufacturer's documentation before designing your ventilation system. Make sure to place the fan pushing air out of the room in a higher place. This is the general practice. It is done this way due to the behavior of hot air. Hot air goes up as they get hotter.

How to program it?

Press and hold “S” (SET) button (2–3 seconds)

This will get you to functions

1. Function I
2. Function II
3. Function III
4. Function IV

Function I — Setting the “working temperature value” of the thermostat

1. You can scroll through these functions with UP and DOWN ARROWS

2. While being in F1 (Function 1), Press “S” (SET) button again and hold it down to change the working temperature.

3. Then you can set the working temperature to the thermostat.

4. You need to keep the “S” (SET) button pressed to change the value.

5. Use UP and DOWN ARROWS to change the value.

6. After getting to the value you desire using UP and DOWN ARROWS, you can LOCK it (Save the config) by pressing the POWER BUTTON once. The config will be saved.

Ex- If you set the F1 (Function I) value to 35C
the thermostat will start cooling when the temp hits anything above 35C.
And the thermostat will start heating the room when it gets below 35C.
(The thermostat will always maintain 35Ctemparature in the given environment, by heating or cooling the environment accordingly)

Function II — Setting the “temperature variance value” of COOL and HEAT

1. Press and hold the “S” (SET) button.

2. Use UP and DOWN arrows accordingly to go to F2 (Function 2)

3. Once you’re on F2 (Function 2), press “S” (SET) and hold to change F2 (Function 2) value. (Press and hold the “S” (SET) button to change the value)

4. Use UP and DOWN arrows to change the value.

5. To save the config, press the POWER BUTTON once.

Ex- If you set the F1 (Function I) value to “35C” and Differential value to “1C” the thermostat will start cooling when the temp hits anything above “36C”. (Working temperature + differential value)

And the thermostat will start heating when the value gets below 34C.
(This happens because the differential value is set to “1C”. This will wait until the current temperature of the given area passes “34C” (working temperature — differential value)

Function III — “Delay value” to turn on and off appliance due to sudden temp changes.
(If you’re using this thermostat with a fridge, this delay will wait to turn on and off the fridge even if the temps go up and down very quickly. This is put in place to protect your device from turning on and off very quickly to match the fast moving temp values. Values here are in minutes. Ex-3 means 3 minutes)

1. Press and hold the “S” (SET) button.

2. Use UP and DOWN arrows accordingly to go to F3 (Function 3)

3. Once you’re on F3 (Function 3), press “S” (SET) and hold to change F3 value.

4. Use UP and DOWN ARROWS to change the value.

5. To save the config, press the POWER BUTTON once.

6. The default delay time value of the STC — 1000 thermostat is 3 Minutes. Leave it as it is. Change it ONLY if you have a good reason to do so.

Function IV — Calibrate Function. You can use this function to calibrate the thermostat against a very accurate reading. (Ex- A thermometer output can be used to calibrate this thermostat.)

1. Press and hold the “S” (SET) button.

2. Use UP and DOWN ARROWS accordingly to go to F4 (Function 4)

3. Once you’re on F4 (Function 4), press “S (SET) and hold to change F4 value.

4. Use UP and DOWN arrows to change the value.

5. To save the config, press the POWER BUTTON once.

6. Leave this value at “0”, if the thermostat temps are accurate. (You don’t need to calibrate it if the thermostat value and thermometer value matches for a given environment.)

Caution

Remember to place the probe (sensor) in a place where you can get an accurate reading. Or your system will go haywire. Just make sure to do that.

Conclusion

STC — 1000 is a very handy tool. I’ll leave a link here for you to buy it, in case you needed one for your own project. Let me know how it turns out. This one saved me a major headache. Now I can leave the thermostat to decide when to turn on and off the exhaust fans.

Click here to get a STC — 1000 thermostat. Thank me later.

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