I have a shop with a split phase HVAC (no ventilation except for open windows). It has a hand held remote to turn it on, select the function and set the temperature. I'd like to install a programmable thermostat (PT). I have very limited information and am going on the thinking that the display board is the point where I'd install a 5 wire programmable thermostat.

Two questions:
1) Based on the diagram below, correct me if you think I'm wrong, CN 2 is where I'd connect the PT. It would be the 5 wire variety likely.
2) What would you consider to be a decent PT? Doesn't need to be a NEST Self Learning type. Just one that is easily programmable and with humidity sensing abilities. Humidity is an important factor in my wood shop.



As for name brand of my split HVAC unit - I'd have to go look and see if I can find a label. It's an off name brand. Works decent.

 

You might be lucky and find a programmable thermostat compatible with the unit, and even luckier if it has a mating connector wired the same.

Alternatively, you could consider using CN7 which is likely to be a closed/open contact to switch the unit on/off – presumably at the set conditions. You could make a bespoke control unit (that only switched the AC on/off) set by your chosen environmental conditions.

Even something like this might do what you want, but may need minor modification to provide the open/closed contact to CN7.

https://www.tlc-direct.co.uk/Produc..._ventilation&version=finalurl_v3&gad_source=1

 

Thanks Hymie for the suggestion. Humidity is not a BIG problem here. Typical humidity is around 35 to 55%. While humidity may be important to preventing wood from warping, the main focus is on getting a programmable thermostat so that it can adjust the temperature an hour before I come in to work and drop it back to a more conservative setting just before or as I'm leaving for the night.

 

It looks a bit like CN#2, with 5 lines, to connect to a wired controller, is where you would connect a programmable thermostat. This block diagram explains more loudly than I can do about the benefits of standards. IF you can get hold of information about the connections that CN#2 is hopefully the key to a working understanding of what here is,