Nest scheduling with eTRVs

nest

#1

Hi all, this is my first post after reading for many months!

So I got SmartThings at Xmas and after renovating our house we’ve added in more Things and I’m getting to grips with all the automation. I’ve got millions of use cases in my head that I need to figure out but the one I need some help with now is Nest & Energenie MiHome eTRVs.I’ve managed to get into GitHub and add in both sets of smartapps & device handlers but it’s scheduling the two together that’s stumped me a little…

We used to have a fairly standard schedule on the Nest to keep temp up during day and down as we went to bed and then used Home/Away to stop necessary boiler time. I’m happy to come up with rules that I use to decide what the temp should be for each eTRV at any given time/state but I don’t know what I should do with the Nest schedule so they don’t trip over each other. I looked at the Nest website which kindly offers that I should just set them all to the same temp and let Nest do all the work, super ‘smart’.

It’s not a condensing boiler so we can’t have it running constantly.

So I’d love some feedback on how some of you are setting your systems obviously everyone’s case is different!


(Meza) #2

Have you got eTRVs on all your rads? If so, really the nest is redundant - and you just need a wireless relay switch for your boiler. How you would link it all together is beyond me at the moment however.

I had a nest with eTRVs round the whole house. The issue would be where the nest was calling for heat yet all the TRVs had shutdown - the system would get really noisy as the boiler had to dump all its heat out of the bypass radiator in the hall.

You really want the TRVs to trigger a call for heat from the boiler, and you can avoid the need for a central thermostat like the nest.


#3

Yes we’ve got eTRVs on all but the bathroom and hall. One of the main things we like the Nest for is to turn it back on remotely when we’ve been away a while so the house warms up on the drive home so will be looking at how we can use ST to better trigger home/away status since auto away is not that helpful for us.

Good to know about the problem, I’m wondering if i could use ST to turn the temp down on the nest if all the other rads are up to temperature to override it? I’m thinking the Nest should be set to hit say 18-19° at 8am, 1pm 5pm and 7pm and then down to 15° at 10pm when we go to bed and then I’ll have individual thermostats on and off around the house during that time depending on how we use the house.

At least it’s 25°C outside so we’ve got a few weeks to figure it all out!


(Wayne) #4

18-19c at 8am and 15c at 10pm? Wow, those are low temperatures at least compared to my household.


#5

Partly it was to accommodate what Meza had said about the Nest keeping the boiler on when all the rooms had heated so having it on the lower end might help with that plus it’s a Victorian house so having the 3 storey hallway at 20/21 is a bit of dream! We also like to keep the bedroom quite cold for sleeping so effectively turn the heating off after 9 and just let the temp drop naturally unless it’s absolutely freezing outside.

We got a woodburner put in our living room when the heating can’t keep up, just need to figure out how to make it work with ST too :wink: