HiLetgo 2pcs W1209 with Case 12V DC Digital Temperature Controller Board Micro Digital Thermostat -50-110°C Electronic Temperature Temp Control Module Switch with 10A One-Channel Relay and Waterproof

While there are plenty of professional fixes for central AC that freezes up, sometimes it's just a combination bad duct airflow, low outside temp, and/or too low thermostat set. Obviously you should make sure you aren't low on refrigerant or the air filter is dirty, but if you have old ducting or a miss-sized unit, it just happens sometimes (especially fall and spring). If your wallet doesn't mind the thousands of dollars to get a new AC installed or otherwise remedied, skip this. For the rest of us, this little gem you just provide it 12V (find an old wall wart, or buy one for a few bucks), cut one of the signal wires from the furnace to the AC (usually 2 of them, carrying low voltage AC, doesn't matter which one you cut), strip the ends on both sides of the cut and put them into the two relay legs (K0 K1), and then tape the temp probe to the copper coolant-in line. Set the setpoint to somewhere a little above freezing (5C or so), set P0 to "C" for cooling, and then set P5 (restart time) to 5 minutes. Now, if the line approaches freezing, it will cut out the AC unit outside while the furnace/air-handler fan still blows air over the too-cold coils warming them up. The restart delay prevents short-cycling the AC. Cheap, easy, works. Will mask a dirty air filter, but you're changing that on a regular schedule, right?

I purchased this product for a little side project. I wanted to add a 12v fan to cool the charging transformer in a battery backup when it is charging on commercial power, but didn't want the fan to run 24x7. The UPS is no longer charging the small 7AH 12V batteries, but rather two 90AH 12V batteries. Installation of the device in the UPS case was pretty simple, but wiring and configuration was a different challenge since this product comes with absolutely no documentation. Keep in mind that this unit only deals with Celsius. If you want to know Fahrenheit, you'll need to convert it. Fortunately, some other reviews here have links to instructions and wiring diagrams. To wire it for 12V power to the controller board **AND** to the load device (fan in my case), do the following: 1. Connect the 12V power source to the +12V terminal 2. Run a short jumper wire from the +12V terminal to the K1 terminal, tighten down both +12V and K1 terminals. 3. On the 12V device, (fan in my case), connect the positive power wire to the K0 terminal and tighten the terminal 4. On the 12V device, (fan in my case), connect the negative return wire to the GND terminal. Also connect the negative return wire from the main power source to the GND terminal. Tighten down the terminal. To program the device for running a **cooling** fan like I did, do the following: 1. Short press "SET" button one quick time and set the desired "turn off" temperature with the "+ or -" buttons. This is the temperature that your fan will turn off once reached. Once you have your "off" temperature selected, press the "SET" button again. This should get you going. If you set the temperature to 30C, the default swing temperature is 2C. This means that the temperature probe must get to 32C before the fan will turn on. The fan will run until the thermal probe drops back to 30C, then shut off. If you want to change the default swing temperature from 2C, do the following: 1. Long press "SET" button until P0 shows on the screen. Press the + button until P1 is displayed. Short press "SET" button to modify that value. You should see "2" which is the current default setting. Press "+ or -" until the desired temperature is reached, then short press "SET" button again to set the new value. If the main "off" temperature is set to 30C like the above example, and you set P1 to 10, then the thermal probe would have to get to 40C before the fan kicks on. The fan would then run until the thermal probe reaches 30C before shutting off.

These controllers work well and you can't beat the price. I'm using one to control a 20W silicone heater for an enclosed butter warmer. I keep the house cool in winter, and I got tired of mangling my toast when trying to spread cold butter. These don't have a parameter to switch from Centigrade to Fahrenheit display units like others do, but no big deal.

This temperature monitor is the heart of my class B RV battery compartment temperature regulator. My 460 amp/hour lithium battery has to be stored above 14°F and weighs 100 pounds. I used the W1209 along with a 70 W heating pad to keep my battery compartment above 19° F. I programmed the W1209 to turn on a 70 W heater when the temperature drops below 19°F, and shut the heater off when the temperature rises above 20°F. In single digit weather the system has performed perfectly I used a X-Sense Wi-Fi based smoke alarm to for an this added layer security in case my electrical system has a problem I will be notified through my phone.

Circuito elettronico semplice, ma ben funzionante e di facile regolazione (reperibili facilmente sul web le istruzioni). Vengono spediti 2 circuiti e due sonde ntc. Io ne ho usato uno per costruire un mini impianto di raffreddamento per un dvr (al fine di prolungarne la vita). Finora funziona perfettamente.Ottimo rapporto qualità-prezzo.

Control de temperatura de un Inversor Vcc/Vac.

Bought these (only in fact needed one) to control solar powered ventilation fans in my greenhouse. Can be configured to operate in cooling (on when set temperature exceeded) or heating (on when below set temperature). There's a couple of degrees hysteresis so it won't oscillate too much. The LEDs show the current temperature and it seems fairly accurate. The temperature probe supplied has a reasonably long lead and is potted into a metal cap, making it waterproof (the board itself will of course need protecting in a box). Configuration is simple, albeit a bit tricky to figure at the start I found. It essentially comes down to up and down buttons to set the trigger temperature. The settings are non-volatile so survive power loss. Was a bit concerned about the current drain given I'm using it in a solar/battery environment. However, even though it has pretty bright LEDs they have minimal drain on my small Li-Ion pack (not enough to discharge it over night anyway).

Works exactly as specified. I use it to control an electronic solenoid connected to a tap which turns on a mister in my greenhouse if it gets too hot. Easy to program too

I used this as a fan controller for my motorcycle. I put the sensor into the radiator fins and dialed in the temperature I wanted to see on the temp gauge. The fan comes on and goes off precisely and crisply compared to the thermo switch that was impossible to find for an older bike. It now starts the fan smartly as opposed to groaning to life with the thermo switch. Just connect the device (+) source power to the running light circuit which comes on when the engine is running. For the fan, provide frame ground, and positive from battery, then through 10A fuse, then through switched relay onboard the device to the fan positive. The programming is simple if you google the device specs on YouTube.