Some years ago, I fitted an OWL Intuition hot water and heating automation system. At the time there really weren’t that many options available and this ticked all the boxes. As a bonus, it had its own cylinder stat which allowed me to set different hot water temperatures for different times, although this isn’t something we used a lot, it was nice to have.
The OWL system worked extremely reliably, the app was great although the lack of development of recent years has been annoying and also the lack of any additional compatible hardware.
Couple that with the addition of a mandatory OWL subscription now, which was only about £20 for 2 years and then the Nest system was on offer at Screwfix so I figured it was a good time to upgrade, the Nest thermostat also looks a whole lot better, very gadgety cool. (If you are interested to see what’s inside, have a look here)
Fitting the OWL originally was relatively simple, and the Nest system was just as easy. The Nest thermostat runs off 12V from the Heat Link unit. I opted to place the heat link in the airing cupboard with the hot water tank next to the 10-way junction box. Mostly because all the heating wires from around the house terminated here and it was out of the way.
Obviously, turn the power off before starting and make sure you have a full understanding of what you are doing, if not, call an expert.
This is the documented wiring diagram:
And this is my version, something to refer to when I was doing the job:
I also ended up with a few spare wires left running up from the downstairs boiler, so one summer when we finally upgrade the boiler, the extra wire needed for the heat overrun won’t be an issue.
The Nest system seems to be working well, it’s early days yet but I certainly don’t have any complaints. Although the Nest’s use of GPS on my phone is chewing up my battery!