I’ve been browsing around for a little while, both scouring Google and these forums but I can’t find a clear solution to what I want to achieve.
In our house we have a standalone boiler, with a hot water tank system for the taps/bath/shower etc, and on demand (no tank) for the central heating.
Currently it is controlled by a Drayton LP522 which is wired to a Drayton RTS1 thermostat. There are 3 wires that go to the thermostat, (240V 50hz) Live, Neutral and Call. Presumably when the thermostat calls for heat it just shorts the Call line to live 240v.
Due to our hot water system being unconventional, i’d like (if possible) to keep the Drayton LP controller, as that has a built in timer for hot water and heating. The current hot water system also has thermostats that are built into the tank, and I think attempting to upgrade the entire system is a rabbit hole none of us have the time (or money) for . Hence wanting to just piggyback the current system and make the central heating a little smarter.
My plan is to set the central heating to “ON” on the LP controller, meaning it essentially overrides the timer feature, then the thermostat can be in complete control of when the central heating comes on. Is there a (reasonably priced) smart thermostat that can be a direct replacement for our old RTS1 that works nicely with Home Assistant? Preferably one that still has an interface on the thermostat so we can just as easily adjust the heating via that, or via the HA app. Home Assistant (or the thermostat) would also act as the timer, as well as a temperature control.
I know you can achieve this by using a smart switch and temp sensors, but i’d still like to retain having a physical knob and a display in the hallway.
If not, i’d be open to suggestions for replacing the entire control system, which would have the benefit of being able to control the hot water via HA too. The only caveat is that the boiler/pump/tank needs to stay the same so I don’t think this is an option.
My current home automation doesn’t go any further than a couple of Matter smart bulbs and plex integration, so my options are open!
(I should’ve mentioned this in the OP) preferably the replacement thermostat takes it’s power from the existing wiring, and sends it’s signal down the same wire. The cable is plastered into the wall so relocating or having any additional boxes in/around the thermostat makes the project alot more complex. Hoping for a straight drop in replacement
Thank you, that looks promising. What controls do you get in HA? Is there a dedicated interface for timing when the heating goes on/off, or is it based on HA automations? The reason I ask is the people I live with aren’t very technical so an easy-peasy UI to adjust that is preferable.
I think I am understanding the data sheet correctly, in that it can still work with the original Call line.
Also, which z-wave hub do you use?
Would you be able to share a screenshot of your home assistant controls for it?
Failing that ,are there any suggestions for a WiFi based one?
I am using Meross MTS200 to control my heating system (methane boiler)
In my case it does not give the 220v but only closes a dry contact (it has NO-C-NC contacts), that makes the methane boiler start the water pump and the heater.
There is a variant for “electric systems” that is able to switch a 16Amps contact with mains power over there (this one).
I am satisfied with this product, I can also make a weekly program (but only if I use its app, not with HA for what I know).
The interface is similar to the one pasted by @templeton_nash , but with an added “mode” dropdown (auto, follows the weekly program - manual comfort - manual night - manual away) .
I’ve been using this Zigbee one for a little over a year now. It works, but I needed to install a quirk to use it with ZHA. That might or might not be needed if you choose to use Zigbee2MQTT.
I think I have a very similar set up to yours. I keep the switch to the heating on (not using the scheduler) and the thermostat handles shutting off at night/when we’re away/etc.
I had a little troubling installing it, but I’m an electrical noob.
Also, I was already a mostly-Zigbee house, at that point, so Zigbee made the most sense. I also have Z-Wave and Matter/Thread devices, but a much smaller number.
Thank you everyone for chiming in. I’m leaning more towards the MTS200, due to the cheaper price and WiFi. I’ve set up a nice system using the “Custom: Scheduler Card” and the HA thermostat card. (using a virtual thermostat device for now), so that covers my control aspect.
. Hence wanting to just piggyback the current system and make the central heating a little smarter.