Automated heating in an old Irish central heating system?

Not sure about anyone else . But as you said there's a large amount of cost options. I decided to successfully dip my feet in at the low cost option to see what the results are.

The outcome is that I have thermostat control. (Can also add multiple temp sensors) I have an app control. I have Google Voice assistant activation. I.e ok Google turn on/off heating or thermostat .

I got all this for the low cost of of two Sonoff TH16 they come with temp and humidity sensors with them pluged in.

I've added each to the supply side of the boiler and the thermostat respectively.

Seperately I bought the best value manual TRVs from Screwfix for all the rads in the house I've 13 so didn't fancy going smart due to cost. Set and forgot worked perfectly for me.

All of above is once off cost with no subscriptions. Should I wish to move on to smarter options I can easily add smart TRV heads to my new trv manual junctions but screwing old off and new on.

If Home Assistant is your thing I'd recommend using it to completely run your heating system, just about any feature you like can be created within HA and the interface in Lovelace can be made as simple or as complicated as you like for the other users. I've done this and everyone in the house can work it with ease. I bought a couple of WiFi Thermostats and the rest is controlled by smart switches and simple temperature sensors of various brands.

Important things to consider in this approach are:

• Devices used should have local control. (your heating should not fail to work because the internet is down)
• Real world controls. (you should still have manual controls in case HA dies)

Here is my config, if its any use to you: https://github.com/Farmer-Eds-Shed/Home-Assistant-Heating-Schedule

Heating controls are simple within the HA App and heating can also be controlled by simple up/down buttons on the wall thermostats.

I started off with Tuya WiFi devices which are controlled by LocalTuya https://github.com/rospogrigio/localtuya but if I was starting again I'd probably go with Zigbee or Z-wave devices as Tuya were a pain to loose their cloud dependence.

With the Immersion heater, it can be controlled by any smart switch but you need to use an additional relay or contactor with most even many which claim to have large AMP ratings.

@comete

Yes mine had 4 wires 2 neutral, permanent live and switched live.

When swapping over live to live, neutral to neutral and the switched live went to terminal 4 on the hive, terminal 3 is hot water. Worked on my APT, the casing had broken and the switch was being pushed inwards. If unsure pls consult an electrician. Tbf it was a straight forward swap in my case.

Oh yeah had to run an earth as well, just looped to existing earth.

If it helps mine started off that simple.

I just replaced an old apt mechanical timer with a smart switch and built from there, in the beginning I just replicated how the timer worked but over time it got a little more complicated as extra devices and features were added.

Be very careful how you control the immersion, a Shelly or Sonoff smart switch are not suitable to directly switch such a large load no matter what their claimed rating is. You should use a contactor for switching such a heavy load then the smart switch can activate the contactor.

This is the switch I used to replace the APT time clock, it fitted the same wall box so it's a direct replacement with a decent switch on it. It's Tuya based though so integration with HA for local control is a bit fiddly but it dose the job and looks the part.

Downstairs Thermostat, connected to zone valve by a radio link, powered by batteries.

Upstairs Thermostat, connected to zone valve by a radio link, powered by USB cable/socket.

Hot press temperature Sensors, currently powered by batteries, but will be converted to a single USB powered device shortly.

Hot water zone valve is controlled with a mains powered smart switch.

Sitting Room temperature Sensor, powered by batteries.

Sitting room TRV actuator, controlled by mains powered smart switch.

Boiler Switch

Immersion control with cover off, controlled by Shelly switching a larger relay.

Immersion control with cover on. There is no manual switch for the immersion, but it's controlled by a Shelly so simple to add either a push button or toggle switch to it.

The above covers most of the hardware components used to control my heating system.

I wouldn't replace the apt clock with a thermostat if it is beside the door in the coldest part of the house, instead put a smart switch there and place the thermostat somewhere more useful. You can then setup Home Assistant to call the boiler when it calls for heat, the thermostat may or may not be connected to a zone valve or TRV actuator. You can install as many thermostats around the house and choose which ones can call the boiler for heat. In my setup the boiler starts if the upstairs, downstairs or hot water thermostats call for heat. The TRV thermostats don't call the boiler but limit the max temp of the hottest rooms, usually just turning of radiators in those rooms completely if the fires are lit.

Yaml from my own config to turn on/off boiler based on state of 3 thermostats. One of the thermostats has a physical smart switch associated, the other 2 don't so input boolean switches are used.

#-----------------Switch on boiler when any Thermostat call for heat, or else turn off-----------------------------------
	- id: 'heating boiler 1'
	  alias: Boiler On
	  description: Turn On Boiler If any master thermostat calls for heat
	  trigger:
	  - entity_id: input_boolean.switch_upstairs
	    from: 'off'
	    platform: state
	    to: 'on'
	  - entity_id: input_boolean.switch_downstairs
	    from: 'off'
	    platform: state
	    to: 'on'
	  - entity_id: switch.hw_zone_valve
	    from: 'off'
	    platform: state
	    to: 'on'
	  condition: []
	  action:
	  - data: {}
	    entity_id: switch.boiler
	    service: switch.turn_on
	

	- id: 'heating boiler 2'
	  alias: Boiler off
	  description: Turn Off Boiler if no master stat is calling for heat
	  trigger:
	  - entity_id: input_boolean.switch_downstairs
	    from: 'on'
	    platform: state
	    to: 'off'
	  - entity_id: input_boolean.switch_upstairs
	    from: 'on'
	    platform: state
	    to: 'off'
	  - entity_id: switch.hw_zone_valve
	    from: 'on'
	    platform: state
	    to: 'off'
	  condition:
	  - condition: and
	    conditions:
	    - condition: state
	      entity_id: input_boolean.switch_upstairs
	      state: 'off'
	    - condition: state
	      entity_id: input_boolean.switch_downstairs
	      state: 'off'
	    - condition: state
	      entity_id: switch.hw_zone_valve
	      state: 'off'
	  action:
	  - data: {}
	    entity_id: switch.boiler
	    service: switch.turn_off

On a separate note do not put too much faith in the current rating of a Shelly smart switch or any other smart switch for that matter especially when it comes to immersion heaters.

I love Shelly devices but no way in hell I'd trust this device with 16Amps, I've worked for a long time as a maintenance engineer and that terminal block is definitely not suitable and the relay itself wouldn't last long either switching 3KW plus loads for hours at a time. Always use a separate larger relay or contactor with an immersion.

I replaced the CH timer with a programmable one with thermostatic sensing. I replced the HW timer with a programmable one. The immersion has a thermostat built in, so if the CH has heated the water sufficiently and the timer turns on, the thermostat should either not turn on the element or if it does, only for a shorter time than programmed until the set temp is reached. Did this nearly 20 years ago, nothing fancy.

Those connectors are typically rated for 10A - keep in mind a Chinese amp is smaller than the one used in the rest of the world

You can buy 5.08mm ones that will do 16A if you want but the PCB traces might not take it. I wouldn't go near Chinese modules for that sort of stuff, source good parts from Europe and make own PCB using good wide traces and possibly 2oz copper

Yes, boiler will only draw about 3-5 Amps, might have higher starting current but a 10A relay would cover it. The Shelly I've used in the immersion has the option of connecting a standard light switch, I just chose not too, would be very simple to add by connecting between the 2 empty terminals.

With the way my boiler is setup, I've the switch to turn on boiler in case of a failure in HA, but it is never touched during normal operation as the heating is controlled by the thermostat. Heating is never actually switched off, just the thermostats are turned up or down either on the wall, with the app or through scheduling. A low temperature setting is set if heating is not needed.

If for some reason HA failed, you'd have to turn on the boiler and turn up a heating zone to get heat, but with HA running, you just turn up whichever heating zone you want and the boiler will automatically start. For this reason I think physical wall controls for setting temperature are more important than the on/off at the boiler especially for the other users in the house.

The rads heat up quicker and absolutely do get hotter. House here has 20 rads, system would struggle to heat them all and the hot water tank to max temperature all at once and it would use much more fuel to try and achieve it. Zoning makes perfect sense for more reasons than just saving fuel, the main one is comfort levels, some rooms are easier to heat than others, shutting off heat in these rooms allows cooler rooms reach a comfortable level without the rest getting too hot, there will also be less energy needed to heat those cooler rooms. I've an oil monitor on my system and one thing I've noticed is oil consumption goes up considerably when hot water zone is used.

Originally I had gas boiler with mechanical timer, one thermostat for the whole house, copper cylinder with coil and electric immersion heater. The rads did not have any TRVs.

First I have replaced rads with electric TRVs that are hooked to sonoff minis that were flashed with tasmota. Each room has Xiaomi BLE temperature and humidity sensor.

The mechanical timer and thermostat was replaced with single sonoff Dual r2 switch again flashed with tasmota.

TRV next to copper cylinder was replaced with electronic one and hooked to sonoff mini. I also created temperature sensor based on esp01 with tasmota. The temperature probe measures the cylinder temperature. The immersion heater is connected to solar diverter and heats water when there is excess solar electricity or I can also turn it on manually to heat from grid.

All above is controlled monitored with HA and Grafana. The house heating and water is done using automation in node-red. All can be controlled from PC/phone/tablet. I have reused old Nexus7 tablet and mounted on the wall on the ground floor. Also all this can be access remotely as long as device has internet connection. As each room has electronic TRV and temperature sensor, each room can set it's own temperature. The heating is set to keep specific temperature based on the time of the day, occupancy of the house and position of the windows. The water is configured to be kept at specific temperature during the day and heat it higher for morning showers. If someone needs to shower then there is an option to heat water with a tap of the button on the phone/tablet. Been running this setup for alsmost 2 years now. It did take some time to tweak automation but now it is stable.