HVAC control panel replacement

Hardware
1

Hey guys,

I have a HVAC and I want to replace it with a cheap wifi controller. Maybe one of the tuya ones. But I cant find anything that mentions these wires?

This is the back of it

image
image684Ă—912 65.4 KB

Thanks

2

Pretty sure the wires connect to something

The something has letters. The new thermostat should have same letters. Just move to matches letter

3

Pretty sure they do to :slight_smile:

Its live, neutral and control. But what is what and what do they match with.

I cant seem to find anything about this. Was hopping someone that had a similar set up could comment?

4

The suggestion is: find the other end of those wires at the heating system. They are likely labeled at that end. That’s generally a good idea anyway because you can’t always trust that it was done right before.

1 Like
5

Thanks,

Its a HVAC, so if I trace it back to the indoor unit I get this CN12, I cant find any info on that unfortunately

image
image684Ă—912 73.1 KB

6

shot in the dark

Red to R/RC (joined by jumber) on new thermostat
Black to W
Brown to G

look for model number of your AC/Heat unit and confirm in manual
The wires may also be detailed on the panel cover of indoor unit

EDIT

youll need to add a C wire from new thermostat to indoor unit

7

What are the functions of the existing control panel? Is it just a thermostat, or are there other control functions? What type of HVAC system is it controlling? Heat only? Cooling only? Heat and cooling? Multi-stage heat and cooling? Fan? Humidity?

I ask because I’ve heard there are thermostats which don’t use old-style on/off signal wires, but instead use a proprietary data protocol. If true, it would mean finding a replacement would start (and probably end) with the manufacturer of the system.

1 Like
8

Thanks guys,

I know a lot of the guys here live up north and are all about heating. I’m in Australia and we only really use them for cooling (Feb is hot, its 10am here and already 28 lol). I actually forget they heat as well, I’ve never used that function.

I have tracked down the company, its some obscure Chinese brand, I’m waiting for them to call me back.

Its just sad this is not more regulated and standardised (especially here where we do force a lot of that)

If someone does come across this post and knows anything about a Aquilon DIV85A, would love a response :slight_smile:

9

It’s possible that the existing thermostat is just an old-fashioned on/off type. Or maybe on/off/fan. Sometimes there will be a schematic in or on the air handler. Maybe on the inside of the cover. Post a pic if you find it. You might get lucky and find you don’t need to replace it with one from the same manufacturer. Good luck!

There are a bunch of knowledgeable HVAC folks over on diychatroom.com who would no doubt know more about it than I. And it’s much more friendly crowd to beginners.

10

Thanks Tom :slight_smile:

Sorry, should have mentioned it has full functionality in terms of modes, temps ect.

But I did find a diagram on the inside of the cover plate that shows what it should be. I’m investigating now, but if someone does see this and can shed some like would appreciate it :slight_smile:

image

11

I’m not an expert, but that looks like S, GND, and +12V. The second two are clear, but S isn’t normal in the old-fashioned thermostat — this seems to tilt toward’s @CaptTom’s theory that it might be a proprietary data protocol line.

12

Yup. I’m guessing you have +12V, Ground and the “S” is for “Signal.” This is probably why it’s labeled as “Wall Controller” and not “Thermostat.”

2 Likes