Glycol Counterflow Chiller build

[TennBrewer]

I decided to make use of an old air conditioner laying around the attic and put it work as a glycol chiller for my Exchillerator counterflow chiller. I live in the mid-south and ground water temps are mid to upper 70s, chilling 5 or 10 gallon batches takes a LOT of water, most of which runs down the driveway, some is saved for cleaning. I thought that recirculating glycol through the CF would be more economical as well as environmentally proper. I have read many of the threads on GC builds using window AC units but most of them are purposed for temperature control for fermenters. Anyway, I have the old Haier AC torn apart and my idea is to replace the existing thermostat with an InkBird controller (similar to STC1000). Also, I need to add power for 2 submersible aquarium pumps, one of which will just recirculate the glycol mixture in the cooler, the other (larger) pump will supply the CF chiller. I want the (smaller) recirculating pump to come on when power is turned ON, the other pump will be activated with a switch. I am not at all HVAC savvy, but I know a little about electrics having built many STC1000's for fermentation temperature control. I am asking anyone out there with some experience in these areas to take a look at my proposed wiring schematic, the original Haier AC wiring diagram is also attached. Comments and corrections would be very much appreciated, I don't want to smoke this first project and have to start over.

 

[TennBrewer]

Elegant design but over-engineered now that I look at it. I am going to just plug the whole unit into an Inkbird controller for glycol temperature control. I think there are way too many ways to screw this up so I am just going to put it back the way it was. Except for one thing: I'm wiring the fan hi speed directly so it always runs on high. Thanks for looking.

 

[cegan09]

I would consider going with your original plan. Each AC is different, but some of them can have their own time out logic to keep the compressor off for a certain period after turning on. The way I wired mine, the AC has power all the time, so the fans are always running, but I control the compressor power with an inkbird and SSR. That way the compressor comes on immediately when asked to, and the inkbird takes care of making sure it's off for enough time (programmable setting).

 

[Drumminguy81]

I just bypassed the controls on mine and plugged it into an inkbird. Working great for 3 years now.. one thing I will mention is that I tried this with my plate chiller a couple years ago and found that the glycol chiller really struggled to keep up almost imeadiately. It did an amazing job of chilling the wort but keep in mind that glycol is returning to the reservoir at a much higher temp so the compressor is running non stop the entire transfer trying to get the glycol back down to setpoint. Not sure about smaller batches but mine couldn't handle cooling an entire 20 gal batch I'm sure a 5 gal batch wod be fine..

 

[TennBrewer]

Thanks to all for your comments. I do have one issue I would like to resolve: the AC temperature sensor is still active and the temp control has been turned all the way to COLD. The weather has gotten much colder so the garage is way too cool now for the compressor to kick in. The fan keeps spinning but the compressor is not running. I need to bypass the AC thermostat now so that the compressor always comes on with the fan. I am looking at the diagram and there are just two wires connected to the thermostat. Can I just pull these off the AC thermostat and wire them together (or keep them apart?).

 

[TennBrewer]

No guts, no glory. I jumpered the thermostat wires together and both the fan and compressor were running.