Each rule in the smart home can consist of triggers, conditions and scenes. Triggers consist of one of more alternative events any of which cause the rule to be evaluated. The optional Conditions consist of one or more statements all of which must be true for the rule to be satisfied. Scenes consists of one or more scenes that are set when the rule is satisfied.
For my heating control I have two scenes that set the boiler on or off, and triggers and conditions reflecting the status of the radiators.
| Triggers | Conditions | Scenes |
|---|---|---|
| Any valve goes to closed .. | .. and all valves are closed .. | .. then cancel boiler. |
| Any valve moves off closed .. | {none} | .. then enable boiler. |
As an alternative I considered rules using temperature, but that would make things more complicated if the temperature set point is adjusted as you might need to change the rules; whereas by having rules based only on (fully) closed and (partially) open then the set point can be adjusted without issue. Additionally you can control around a very low vacation set point for frost protection. Effectively there are four set points:
- Closed – which is forced by a summer setting, but also occurs at other times when no heat is demanded.
- Vacation temperature – 5 C for me – a low set point for frost protection, but from which it might take an extended period to warm up.
- Economy temperature – 10 C for me – a lower temperature limit during normal scheduled operation.
- Comfort temperature – 24 C for me – a minimum temperature avoiding complaints from my wife!
My system retains the original 7 day timer, which these days I use only to control water heating. If I did enable the 7 day timer as well as the smart controls then the boiler would be enabled when either the 7 day timer or the smart controls demanded it.
