I’ve got a Google Nest (1st Gen) which has worked well for years but it doesn’t support hot water control, only heating.
For hot water I rely on my Honeywell dual digital timer to turn on/off hot water. The Nest is connected directly to the timer and we have set the heating to be “always on”. This allows the Nest to turn the heating on/off based on it’s own scheduler.
The Honeywell dual timer has 6 pins that provide power and signalling (I presume) to the central box which itself controls at least one valve and also when to turn on/off the boiler.
| 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|
| NEUTRAL | LIVE | HW OFF | CH OFF | HW ON | CH ON |
HW = Hot Water
CH = Central Heating
My question is, can I somehow insert a smart switch (Sonoff perhaps) to activate the Hot water (HW) and then use HA to control schedules etc. Of course, I would then set the existing timer to have hot water AND heating always on.