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Xringer 04-29-16 07:10 PM

Built your own split system?
They have these new gizmos now, and they look interesting..

Universal Split Air Conditioner Control System A/c Control Board - Buy Air Conditioner Control System,A/c Control Board Product on

"Universal split air conditioner control system a/c control board".. Universal Deluxe AC Control System Replacement For Minisplit Ductless AC: Electronics

"Universal Deluxe AC Control System Replacement For Minisplit Ductless AC"

Someday, they'll make one to work with an Inverter system..

jeff5may 04-30-16 12:50 PM

Sir, you just made my day. I'm buying one of these TODAY to stick on my current beast.

Not eligible for prime shipping, which means it's not coming from an amazon warehouse.
Tell you when it gets here.

Xringer 04-30-16 01:06 PM

Good luck with being the 1st on your street to try one.. :)
(We were first to own a microwave oven, on our street).. ;)

I was thinking if the loads are too big, maybe other relays or SSR could be subbed.?.

I'm trying out some meds (for the tree pollen).. Wife's birthday dinner tonight.. No beer.. :(

I saw one of those units (Chinese site) that said it had "Reset" as a selling point.
Maybe it was a power-fail-restore type thing..

jeff5may 05-01-16 08:32 AM

Looks like the control has 30 Amp contactors for compressor and aux heat, 7 Amp sugar cube relays for everything else. Main thing I'm worried about is what comes out of the relays? Line voltage? 12VDC? Neutral? My guess is it switches one line leg, like your Sanyo control board. In that case, I will have to either switch coils on my reversing valve or use a doorbell transformer to get 24VAC. Maybe I'll get lucky and the designers put low voltage coming out for the reversing valve.

Found a close-up shot of what should come in the box:
I wonder why the wall and remote controls don't match? Maybe they had extra Hayashi remotes that week.

I'm not a licenseded HVAC tech, but I think I am certificated enough to install this device.

I have my fingers crossed that all 3 temp sensors will be in the box (ambient, pipe, defrost). The unit description says it does, but you never know...

Xringer 05-01-16 09:10 AM

In other pictures, it seems like two sensors were copper and one was black encapsulated.
U12A Universal air conditioner control system with PCB, wall mounted control and remote control

The "instructions" are just a couple of pictures..
The 4-way valve on my Sanyo is 230vac.. So, it seems like you should be able to use a step-down transformer. See Ebay..

jeff5may 05-04-16 08:11 PM

4 Attachment(s)
The package came in the mail today. USPS Priority Mail from Hollywood, Florida. Yay! I don't know where the pics and such came from, but the stuff in the box I got looks just like the label on the box. And it did come with three sensors. No batteries for the remote control, though.
Top view of the control board
The two chips on top of the board are identical. They are buffer chips that are being used to control all the relays and the swing motor. Just about the same as any random window shaker unit.
Checking the bottom of the control board reveals that everything is switched by one line of the power cord. This means I will have to conjure a way to make it run correctly.This also means it can run off 110 or 220 Volt (or both with relay mods for a couple bucks...) line power. If the board was transplanted into something like Xringer has, but with a single speed compressor, it could very well need no extra work besides wiring. The chip on the bottom is the embedded controller. Someone could probably find a programmable controller with the same pinout as this chip if they looked.

jeff5may 05-06-16 05:11 PM

4 Attachment(s)
Got the unit rigged up today. I have some accommodation to do.
Before shot of the victim: a whirlpool 1 1/3 ton twisty knob window unit with reversing valve added.
Attachment 6937
The thing wired up dead easy. No cutting wires or crimping connectors at all. Basic wire color coding / matching skills required. Once it got turned on, I figured out a problem: the reversing valve is active in heating instead of cooling mode. So it is trying to cool in heating mode and vice versa. Like I said, a cheap (or maybe free, if the on-board reversing valve relay has a normally closed contact) relay mod will change that. If I hadn't lost that coin toss, I would have had a "correctly" operating unit without any extra work.
Attachment 6939
I tapped into the other hot line for the "neutral" connection for the board. I had to run one extra wire: a "neutral/ground" wire to the doorbell transformer I am using to energize the reversing valve. All I have on hand is 110/24 volt doorbell transformers.
Attachment 6940
I ran out of free time today, so I left the unit in its current state of almost working perfect. Still haven't looked for remote batteries yet.

EDIT: I did a little research today, and found that the sugar cube relays in this controller (HRW-112LM1) are form A, which means SPST normally open contacts. I will either have to find a replacement relay that is form C (SPDT contacts) and swap the RV relay or rig in a logic inverting transistor to make it do what it should.

jeff5may 05-07-16 07:22 PM

OK, so I rigged my countermeasure in today. I found a few relays, but they were all the wrong size to fit in the board. I robbed an NPN transistor out of one of the donor boards ( a PN2222a, Fairchild equivalent of 2N2222) and rigged it between the micro and the relay driver IC. I desoldered the input pin from the board and filled the gap with super glue. I found a good ground on the board (hole for a capacitor not stuffed) and stuck the emitter of the NPN in it. I tacked a 10K resistor between the micro output pin for the RV and the base of the NPN. I twisted the end of a leg of a 1K resistor around the driver IC pin previously desoldered and removed it. I melted a teeny blob of solder into the eye and tacked it onto the end of the pin. I twisted and tacked the leg around the NPN collector, then ran the other leg of the resistor to a regulated 5 Volt hole in the board (other leg of the capacitor not stuffed: C5 next to U3). See pics in previous post for reference.

Long story short, the transistor did its job. The thing cools in cooling mode and heats in heating mode. Got everything stuffed back inside the unit, secured parts with screws, and set it to cool the outdoors while I washed my car. I took some pics, but they all ended up smeared or out of focus enough not to be proud of. The awesome thing today was finding out the control panel in the kit is nearly exactly the width of the bezel for the twisty knob plate. Plus I found some batteries for the remote control and played with the unit that way.

iamgeo 05-08-16 04:37 PM

Sooooo, what does this do?

jeff5may 05-08-16 07:30 PM


I believe the main, original intention of the manufacturer was to provide an inexpensive solution for window and mini-split owners whose units have suffered a control board failure, keypad failure, struck by lightning, etc. Original, factory control boards are very expensive to replace. Complete system replacement even more not cheap.

Xringer experienced one of these failures recently, and the cheapest, refurbished control board available for his unit is around 300 to 400 dollars (depending on the source). A whole new system is in 4 figure territory. This line of controls will not work with his system, because he has a variable-speed compressor. These controls will only work with single-speed compressors. I'm really glad he shared the link, as this type of control is perfect for the hacked heat pumps I tinker with.

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