Vokera 29ci opentherm module?

FreeBear

Bendy_House said:

FreeBear said:

Bendy_House said: From what I understand of Opentherm, it's a more 'delicate' type of temp control. So, unlike most normal systems which are controlled by a room stat, and get the boiler running, at full rate, until that room temp is reached, and then turns the boiler off, and then turns it back on when the temp drops to suit demand, 'Opentherm' instead works out when the desired room temp is being reached, so backs-off the boiler in advance so that it arrives at that temp without any overshoot.

OpenTherm is just a bus & communication protocol specification.

The bus specification is point to point over two wires with a maximum length of 50m. Connecting multiple devices to an OpenTherm bus will require a dedicated hub (or devices that can act like a hub).

The communication protocol defines a set number of "messages" along with how the data is passed from (for example) the boiler and the thermostat. The OpenTherm specification does not define how the data is used or any "smart" function on top.

If you want smarter control over your heating system such as outside temperature compensation or predictive boiler run times, you need a smarter boiler or an intelligent control system. OpenTherm just provides a backbone for the two to talk to each other. OpenTherm will not, in its self, save you any money. That will be down to the intelligence of the system and the end user.

What am I confusing it with?!

There's a system where the room stat doesn't just tell the boiler when the temp has been reached, but when it's getting close, and- I think - how quickly. The boiler then modulates in response to it doesn't overshoot, but it also tries to MAINTAIN the desired temp, instead of clicking on and of below and above it.

Summat like that.

Some of the Hive controls will do that. Drayton Wiser also supports the OpenTherm protocol. Pretty sure other control systems offer similar functionality.

Interface boards for OpenTherm are really simple, and there are plenty of examples linked up to Raspberry Pi, Ardunio, and ESP32 boards - Plenty of scope there to plug in to a home automation system.