Changing thermostat temp set point via eDLT

Shocked to discover that the C-bus thermostats I bought CAN'T be controlled by an eDLT. This makes them pretty useless for me. Surely there must be a way to achieve this? Otherwise what was the point in them?

There's gotta be a way to hack it together, or else by using logic? If anyone has any ideas please let me know.

 

Just curious. Given to can change the set point with the thermostat, why do you want to change it via an eDLT?

 

The same reason people use the remote control when they change TV channel - because it's handier.

I have an eDLT at either side of the bed and one in the living room so me or my partner can control the lights/fan/alarm and hopefully temperature.

I've figured out a way to hack the heating controls using scenes and dummy lamps, but I'd really prefer to remove my existing cloud based smart thermostat and do it all within C-bus.

There's gotta be a way to adjust the set temperature on the C-Bus thermostat using logic somehow. Otherwise it's just a dumb thermostat, and there'd be no point hooking it up to C-bus.

 

The only devices that supported the hvac protocol were the touch screens, wiser I & II, and the Pascal Automation Controller. Schneider dumped all of these (including the thermostats) and replaced them with the SHAC which doesn't support the hvac protocol. A major backward step in my opinion as the Cbus function in the SHAC are very limited and poorly implemented. But that's progress for you.

The Pascal Automation Controller is the simplest solution (albeit a bit of a learning curve) but it will give you a lot more options to control the system.

Alternatively if you are handy with any programming language, you can talk to CGate directly and do anything you want. If you have a serial interface and a spare PC it's a no cost option.

 

Thanks for the detailed reply.

Yeah I have my C-bus setup permanently connected to my home server over RS232.

The PAC seems to be the cheaper option rather than buying software licenses etc, so I'll probably go for that if you're 100% sure I'll be able to make it do what's needed.

 

Thanks, Nick.

All I need it to do is switch a boiler on/off via a single relay. There's no other fancy stuff. I assume I just assign a spare relay? Hopefully I can just use one on the same module that I share with lighting?

 

I had a PAC lying around so I connected it to my Cbus network, wrote a quick bit of logic to convert a lighting value to a set point, loaded it into the PAC and it works fine. You just have to set up the eDLT for nudge with a value of 1 and it will allow you to change to set point and show you the current value. Note if you also want to see the temperature you will have to use a separate widget. If you install the thermostat you can try this out in PICED without buying a PAC first. I can send you my test project to get you going.

The relay you pick really depends on how the boiler is controlled. If it's low voltage you can use any relay, although whether you can mix low and mains voltage on a single relay depends on your local regulations. Personally I would never do this. If your thermostat has relays they are designed for common 24v applications.

If you are switching a mains boiler that's a job for an electrician and they need to check the boiler rating to make sure it's compatible with a Cbus relay. Better still, use the relay to control a contactor that controls the boiler. I regularly use contactors with CBus relays because replacing a contactor is much cheaper than a Cbus relay.

 

That's amazing, thanks so much for all your help with this! All I need now is to acquire a PAC somehow

Will report back when I've acquired one!

 

So the PAC has arrived! Can you send me your code please

Still not sure how to read the temperature data from a Hive thermostat though and get it back into C-bus through Home Assistant.

 

Unzip and open in PICED. You will have to select your Cbus project.
Then open the logic engine and go to the HVAC module. It will tell you what to do.

How are you connecting Hive and Cbus to HA?

 

Thanks so much!

I'm using a HA custom integration that connects directly to the C-gate server. No MQTT broker or anything like that. It's pretty new and works very well.

 

Still struggling with getting the temperature from Home Assistant to show on the eDLT. Did you ever come uo with any other ways of doing it? Something about the Measurement app?