Tapping into brivis central heater control panel

Hi everyone :slight_smile:

I was really hoping people might be able to give me some guidance on how to ‘tap into’ my brivis central heater control panel.

I’d really like to be able to remotely turn on the heater (it doesn’t have a timer) without having to setup a servo to press the button!

I’m assuming that the battery powered control panel sends a command to the heater unit on one (or more) of the 3 pins that plug into the wall mount to turn the heater on (or off).

Can anyone think of a way I can ‘capture/record’ this command, to be able to ‘play it back’ by soldering some connections onto the pins (assuming this is even possible)?

Note - there is only 3 buttons on the front of the unit - temp up, temp down and on/off (combined into a single button).

Please see the attached photos for further info - if I can answer any questions that will help, please let me know!

Thanks in advance!!

I'm assuming that the battery powered control panel sends a command to the heater unit on one (or more) of the 3 pins that plug into the wall mount to turn the heater on (or off).

No, it likely uses a solid state relay to control 24V power for the relays that power the blowers and heating in the HVAC system. That's a constant signal, not a one off "turn yourself on" command. You could of course build an arduino based controller of your own to do the job and then use wifi or ethernet or radio to control it remotely.

wildbill:

I'm assuming that the battery powered control panel sends a command to the heater unit on one (or more) of the 3 pins that plug into the wall mount to turn the heater on (or off).

No, it likely uses a solid state relay to control 24V power for the relays that power the blowers and heating in the HVAC system. That's a constant signal, not a one off "turn yourself on" command. You could of course build an arduino based controller of your own to do the job and then use wifi or ethernet or radio to control it remotely.

Thats been my experience as well. When we're working on a house in the winter, and the electrician hasn't hooked up the heater controls yet, we usually just put a wire nut over those two wires (the white/red ones in the picture) until it warms up in the building. The third pin is usually for an additional fan motor or A/C unit, and seems to be disconnected in your picture.

I honestly didn't even think about building a controller - that's a bloody great idea!

I don't suppose anyone could give me some hints on how to go about building something like this, could they?

Based on the information above (i.e. that you can switch on the system by bridging the red/white terminals), is it correct to assume that the controller just bridges these until the thermostat senses that the room has reached a specified temperature, and then stops bridging the terminals (and the cycle repeats)?

If this is the case, I think I'd be fine with building this project using a temperature sensor, relay etc. I'm not overly fussed about having a display that shows the temp the system is set to (although it might be fun to build this later).

Eagerly awaiting your replies!

Not sure if I am too late here. I have the same brand climate controller at home and am thinking of building a remote access to turn this on too.

I am currently working on my garage door. The idea is that I have a base unit that have ethernet shield that are attached to my router. This base unit will be talking to another unit to open/close my garage door using RF.
The idea is I would like to be able to expand to the climate control by adding another RF to talk to the base, which will be controlled using node.js web service.

I am up to combining the ethernet (ENC28J60) shield and the RF (Nrf24L01+), not sure how this will turn out yet as both device has to be on listening mode all the time whereas SPI device can only have one device to LOW at once. Anyone have any ides? have anyone have this problem before?

If I were to do this, I would look into the controller unit, instead of playing around with the big cable on the wall.
I will study the on/off button, use the multimeter to see what is being triggered at the time the button is pressed. Then you can simulate the same action with Arduino.

Does anyone have more to report on this? I'm just getting into Arduino and openhab and would love to hook my Brivis heating in too...then the evap cooling for summer.