FamilyMall High Accuracy Digital Temperature Controller Temp Alarm Thermostat DC 12V 20A LCD for Cooling Heating Meter

It works a treat , instructions aren't to clever , but there are s few youtube videos to help you get set up .

This is NOT an LCD device, it has an LED display, and thus draws approximately 30mA when running @ 12 volts. It dissipates approximately 0.36 watts.The display shows the set point temperature on a small blue three digit seven segment LED, and the measured temperature on a larger three digit red seven segment LED.The device is easy to set up and program, with a simple set of menu options, which it stores, even when power cycled.As suppliedm the temperature displayed is not that accurate, however there is a setting that allows a correction to be added or subtracted from the reading, making the reading accurate when calibrated.The device allows for cooling and heating control, using a programmed set point temperature and a small hysteresis offset.THERE IS A BUG IN THE SOFTWARE.The menu provides a setting, H or C, for controlling if the relay switches on above, or below the set point temperature. Unfortunately, in cooling mode, the relay does not work as expected when used to controlling fan. The relay does not switch on until the measured temperature reaches the set point temperature plus the offset value of a few degrees, and only turns off when the measured temperature is again at, or below, the set point value.Normal logic would expect the fan to turn on when the set point temperature is measured, and turn off again a few degrees below the set point temperature. Thus limiting the temperature rise of the equipment being controlled.

These are great I use these for keeping my batteries warm in winter,downside no instructions.i will list how to set.Po cool or heatP1 I set to 0P2set max tempP3min tempP4temp correctionP5deay startP6alarm tempP7data lockP8factory reset

I see some people are saying this works the wrong way, ie the relay contacts are closed when hot, fine for a fan cooler, but no good for a heater. It can be changed easily, along with lots of other parameters. Search W3230 manual for the full gen, but here's a taster:Press and hold SET until P0 appears in the top red display, along with either C or H in the bottom blue display. If you want a fan to cut in when things get hot choose C, or use up/down buttons to choose H if you want a heater to cut out, then press RESTART. Job done, but don't put a lot of current through the relay, use it to drive a bigger one or a triac module.

After a few months testing this unit started showing 100+ degrees as the ambient temperature in a tank of cold water. Couldn't get it to show the actual temperature after that, and so the unit became useless. Tried resetting the unit, that didn't work. Waste of money, but more importantly a waste of time.

great item however only 4 stars as no documentation. have no idea of various menu and program options.Also you will need basic electrical knowledge to wire up switch circuit. Pretty straight forward if you are able to wire a one gang light switch or home heating thermostat.

This thermostat/controller works well and does exactly what it claims. However, a simple set of instructions would be very helpful. The menu includes several settings that affect how the unit operates. Some I have worked out by trial and error but others are still a mystery. In all other respects I am very pleased with it, especially given the low price.

Bought it for automatically switching on and off a fan for cooling the lithium battery storage box in my micro camper in summer. Trials on delivery showed it worked fine for the job and I'm hoping it will last a good while. One star deducted for lack of instructions