I would like to by-pass the controller for a room AC (Kenmore) and use an external controller similar to a Johnson. Any help would be appreciated.
use this…
and this…
Coolbot. Not cheap, but worth it.
For my cool room, I pulled the temperature sensor out through the front of the A/C and have it fed into an insulated can that has a night light inside of it as a heat source. This makes the A/C believe it is always warm in the room. The insulated can and the Johnson controller run on a timer so that the A/C shuts down every two hours at a minimum (concerned about freezing the coil).
I can maintain summertime temps into the 40s, though I rarely take it below 60 these days. It’s really more for wine, but also works as a large fermentation chamber.
The only significant cost was the Johnson controller. If I did it again, I’d use an inkbird or an STC-1000 (same basic thing, but C readout).
Thanks for your help/suggestions. I currently have a STC-1000 controller for the area. I am considering Stevie’s suggestion but was hoping for a way to bypass the internal AC controller to make it run when the STC-1000 supplied power. Any info on the bypass?
I think that the bypass will depend on the model of the A/C. When I researched this a few years ago, I found it simpler just to trick the internal A/C temp controller by heating it, rather than bypassing the controls electronically. So, basically, I can’t help. Sorry!
Mine works functionally as you desire, it’s just not as elegant. But it’s also easily reversible, which was nice when I went to larger A/C.
This is the basic idea on how the coolbot functions but it also has some protections built in to prevent freezing.
My Rube Goldberg approach was to put the whole gig on a timer to give any potential freeze up time to defrost.
Take the leads to the internal t-stat and wire nut them together. This will make it run constant so that you cn turn it on and off with your STC-1000.
Thanks all for the help. Since I only plan on using the room for temps. down to 54F I am hoping there won’t be any freezing problems. If I do the suggestions on Coolbot & and night light in a can can be tried.
For “weazletoe”, the internal “t-stat” you mention, is that the cool-side temp. sensor?
I’d be careful about powering an AC unit with the STC-1000- the STC is rated for lower power applications only. I’m guessing an AC unit would fry it. The coldbot was created to handle this application.
Not sure what you mean by “cool side sensor”. I’m just making an assumption that you have an a/c with with a mechanical dial like stat. There should be two power wire on it. One hot, going in, and one out that is hot when the stat calls for cooling. cut these two off the stat and nut the together. The A/C should run 24/7 when you do that.
Or, you should be able to run the SSR that I linked to with the STC-1000.
Exactly. The STC 1000 can be used to switch a higher amperage SSR.
Most of the newer A/Cs that I’ve encountered have digital controls and no longer have the mechanical dial. I believe it becomes much more complicated to override the sensor on these. Maybe not. I don’t recall for sure, but it was enough of a bear that I skipped it.
Still the same thing. You got 110v into the board, and 110v coming out. find them and tie them.
I do have one of the newer types with the digital controls which appears to make the by-pass more difficult. Also, my AC unit is on the small size (5300Btu) and uses 490 watts which should be OK. I am not sure about the startup power surge and it’s impact on the STC-1000.
As far as incoming cool air sensor, the electrical schematic I have for a different brand AC unit had 4 sensors which is why I mentioned which sensor.
Thanks again for all the helpful comments.
Thanks, person who looks just like Eminem and is most definitely NOT a spam-bot