Looking for a thermostat control module that's capable of Fahrenheit

[albert001]

I need to control some AC and DC fans in order to control room and equipment temperature.

I currently am looking for one with 12 volt dc pwr input and 12 volt DC output to control a 12 vdc fan.

I'm also looking for ones that can accept either DC or AC pwr input to control 110/120 VAC fans.

I've come across many temperature / thermostat control modules online such as e.g. W1209, W3240, W1401, W1308, etc.

However it's unclear which are capable of displaying temperature reading in Fahrenheit.

I'm wondering if anyone here in the forums have  experience with these modules and know which models (if any) are capable of Fahrenheit readout. Residing in the US I don't normally think in Celsius and usually can't determine Fahrenheit from Celsius without a conversion tool or making math calculations with pen and paper.

[albert001]

After some more searching I found a W1209WK that's  described as switchable between Celsius and Fahrenheit modes.

https://www.ebay.com/itm/1x-Digital-LED-Microcomputer-Thermostat-Controller-Switch-Temperature-Sensor-12V/202575748363?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[amyk]

If they use the same firmware as that one, they should. Read the instruction manual for the details.

[albert001]

Some only have generic or no instruction manual so it's difficult to determine, unless the seller has information if they are capable of switching between Celsius and Fahrenheit

Also some may or may not have updated firmware for a Fahrenheit mode and the sellers aren't usually up on technical details such as firmware, display modes, etc.

[james_s]

How often do you need to change the temperature? If it's a set it and forget it type thing then it shouldn't matter what format it uses. For something like a fan I'd be tempted to just build my own temperature controller using an op amp and thermistor with a pot to set the temperature, add a little positive feedback to create hysteresis and you're set.

[albert001]

I purchased a few of modules that are being shipped from China. I think some have Fahrenheit and Centigrade while others  have only centigrade.

Purchased this one for $3.79. Shipping from China it take a while for things to arrive.



https://www.ebay.com/itm/1x-Digital-LED-Microcomputer-Thermostat-Controller-Switch-Temperature-Sensor-12V/202575748363?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

As you can see from the pic there is a C/F switch, that appears to be able to switch from centigrade to Fahrenheit

I have an Xantrex Trucharge2 charger where the case fan is constantly running, never turns off. I'm told the fan is temperature controlled and suppose to only come on when the case temperature reaches a certain level.

So I'm going to detach the 12 volt case fan and plug it into the thermostat which will be connected to 12 volts power from the charger.

[james_s]

I would look at why the fan isn't being controlled properly rather than hacking in a separate controller. Either there is a fault in the unit or it is configured improperly.

[albert001]

I opened the case to inspect the pcb and there's no way to inspect unless removing the five large heat sinks that cover most of the circuits on the PCB.

It  is out of warranty and the min cost for an electronics repair shop is $100 hour with an hour min to even have it looked at.

Unless you have a service manual there's really no way to repair it your self unless you happen to be familiar with Xantrex Truecharge2 pcb design and layout.

To have it repaired would likely be only from an authorized Xantrex service center. Cost would be more than I would want to pay just to have the fan circuits repaired.

I don't really know exactly how the fan is suppose to operate as the information I have are only opinions from a few other owners who thought or guessed that was how the fan operates.

Sure if I could find any temperature controls circuity and a temperature sensor I could perhaps see if there's a  problem with a sensor, etc. but as I stated there's really no access to it's pcb unless you are able to remove it's heat sinks.

The fan controller isn't a hack. It's basically you disconnect the case from a four pin plug on the pcb. Then power the fan from  separate power connections from your own fan  controller with heat sensor that allows it to turn on and off the fan using your  own min and max. temperature setpoints. 

So essentially your separating the case fan from the chargers pcb fan controller and adding your own fan controller to perform the same operations for fan control.

The best thing to do would to replace the Truecharge2 with another one but the cost would be at least ~$225.00.

So I can either let the fan run all the time or just add my own fan controller, that's separate from the charger.

The case fan only duty is to keep the pcb and case cooler that it's heat sinks are capable.

Earlier models of the Truecharge used large heat sinks and there was no fan. I think the fan Truecharge2 only exists when temperatures become too high for the five heat sinks on the pcb to handle.

[grifftech]

any hvac thermostat