I currently have a single Secure Thermostat and Secure Boiler receiver controlling my heating. The thermostat is associated with the receiver via Group ID 2 and this is all working great. The relay turns on and off as required by the stat’s set point.
I’m ready to take it to the next level now and have a box full of additional thermostats and Danfoss valves. I want to have a multi-zone system whereby I can split the house into different temperatures depending on scenes. This is all well documented and straightforward until it comes to deciding whether the boiler is on or off. It’s likely that the stats will all have different requests and will end up sending conflicting signals to the relay which I want to avoid.
My plan (so far - it may change) is to introduce a custom-coded device and associate all the stats with that instead of the Secure Receiver. This device can then field all the requests and perform the logic to decide on the correct command to send to the relay.
In order to create this device I need a good understanding of exactly how the thermostat / receiver association is working. Something is obviously going on under the hood that means when the stat is associated with the receiver via group ID 2, the correct commands get sent, but I can find no reference as to what is going on. I only knew to use Group ID 2 because Vesternet had some notes on it - no idea how they knew. I believe I need to make a new device based on either D_Heater1.xml or D_HVAC_ZoneThermostat1.xml. If I get it set up correctly, that stats should be able to talk to it exactly as if it were the relay.
If anyone has any insight into this I’d be grateful. My only option at present seems to be “trial and error” by twiddling the dial on a spare stat and watching the log output from a custom device, but that’s going to take an age.
Associations are Z-Wave device to device messages.
These can be seen if you have a secondary Z-Wave controller joined to you home network … and you have some software that allows you to sniff the Z-Wave messages the controller sees.
Vera Does not provide a way to have a Software/Plugin device be the target of a Z-Wave association.
You can have a bunch of Z-Wave relay switches that are wired in parallel to drive the Boiler.
One to one correspondence between Thermostat and a Z-Wave switch.
When ANY Thermostat calls for heat, it will engage the corresponding switch.
If any switch is on … the boiler is on.
Or you can do this in Software …
USE PLEG to monitor the Z-Wave thermostats.
If ANY Z-Wave thermostat is calling for heat … turn on the SINGLE Z-Wave switch that enables the Boiler.
Thank you for the reply
Vera Does not provide a way to have a Software/Plugin device be the target of a Z-Wave association
That’s a real shame, and possibly a deal-breaker. When you say Vera does not provide a way do you believe this means it cannot be done, or just that there isn’t a GUI to do it?
You can have a bunch of Z-Wave relay switches that are wired in parallel
Interesting but bulky and expensive. I think I need to try harder on a software solution first! Your description is basically what I want to do with software.
USE PLEG to monitor the Z-Wave thermostats
The problem I see with that is it becomes a “pull” system by reading the stat rather than a “push” from the stat itself. The vendor claims to have an algorithm optimised for controlling the boiler, which would be lost using this method (although I don’t know whether that would actually make any practical difference).
Unless I’ve misunderstood how that would work of course. Would PLEG be reading the last known room temperature or is it monitoring changes in variable from the stat?
When the thermostat reports or when it is polled it updates the Vera property. If PLEG is connected to that property it gets notified by the change.
I do not know if Vera polls your thermostats or if the thermostats announce a change in temperature.