Central Heating automations

Configuration
1

I have a Baxi Back boiler and have worked out if I set it to on all the time and use a smart plug I can control it using a zigbe thermometer I have. Basicaly when the plug has power the heating goes and and when it does not it shuts off.

I decided to create a automation to turn plug on when temp goes below 15

alias: Lounge Heating on < 15
description: ""
trigger:
  - platform: numeric_state
    entity_id:
      - sensor.lounge_temp_temp
    below: 15
condition: []
action:
  - service: homeassistant.turn_on
    target:
      entity_id:
        - switch.lounge_plug_baxi
    data: {}
mode: single

and off when it goes above 19

alias: Lounge Heating off > 19
description: ""
trigger:
  - platform: numeric_state
    entity_id:
      - sensor.lounge_temp_temp
    above: 19
condition: []
action:
  - service: homeassistant.turn_off
    target:
      entity_id:
        - switch.lounge_plug_baxi
    data: {}
mode: single

Currently the heating is 20.5 and the plug is not being turned off :frowning:

Any idea what is going on?

2

Numeric State Trigger will only trigger when it passes the value.
So when above 19 any other values above that wont trigger this again.

Having said that, what does the trace say for this automation?

3

Thanks, I was thinking this may be the case and did some diging and just changed the turn heating off automation to

alias: Lounge Heating off > 19
trigger:
  - platform: state
    entity_id: sensor.lounge_temp_temp
condition:
  - condition: numeric_state
    entity_id: sensor.lounge_temp_temp
    above: 19
action:
  - service: homeassistant.turn_off
    target:
      entity_id: switch.lounge_plug_baxi
    data: {}
mode: single

Seems to be working now

4

You need to use the generic thermostat, its what its there for.

1 Like
5

Seconded. It allows you to choose your own sensors and control entities and then you can work with it like you would a normal thermostat. I use these all over the place in my HA and itā€™s much simpler than scripting/automating my way to happiness.

6

I agree if I was just trying to tempriture between 2 tempritures but what I am ultimatly doing is a lot more compled.

I am having temp up to 19 degrees for a cople of hours in the morning, then during the day making sure it is at least 17 degrees, then having it up to 19 for a few houres in the evening. I am also puting the heating on for an hour if it ever drops below 15 at night.

I am efectivly doing what modern heating systems do, have a number of from-to times with diferent tempritures at diferent time bands.

My understanding is generic thermostat is just for keeping temp between two temritures.

Maybe there is a more complex heating widget that can do all this?

7

Yes, more or less, but in your system you have lots of sensors to remember and this all adds complexity where one isnā€™t really needed. So instead of having to set one helper to this and another to that, you instead lead one single entity manage what needs to be controlled and you just tell the thermostat to set the temperature for 1 hour and it know what to control, for how long and when to turn it off.

8

Once you get the automation working a couple of items to consider

a) what happens if the temperature sensor fails and the boiler stays on indefinitely? Can you detect that failure?
b) what happens when the smart plug fails (they have a life expectancy of ~3 years), does the house freeze up?
c) what happens when HASS fails or the computer itā€™s running on?

Turning off a boiler and letting it cool down in a frequent basis causes metal fatigue which will cause premature failure this is why most boilers maintain a temperature of 150 or so.

9

The reasons you list are the reasons the generic thermostat has different modes so you can do a simple timed automation to switch between the modes so you donā€™t need all the rest of the complications. Unless you really fell the need to reinvent the wheel.

1 Like
10

Exactly this. I have mine set to 19Ā°C for ā€œcomfort modeā€ when people are in, 17Ā°C when itā€™s just me working from home and 16Ā°C at night.

Mode switching is done via automations triggering off time and zone occupancy.

Barely ever needs manual intervention.

11

Exactly mine has been running now for years using a wemos mini a temp sensor and a relay, once set just leave it to it.

12

Can you point me in the direction for more on this. I knid of get what you are talking about but not quite sure. Are you saying I could have a Generic Thermostat and helpers to change the settings?
Also is Generic Termostat:

type: thermostat
entity: climate.benroom_ben_ac

Also there seem to be few woth options

My requierments are

  1. Always keep tempriture about 15 at night
  2. Always turn off boiler if tempriture gets above 19
  3. Turn on if tempiture under 19 between 0600-0800 (to make sure house is warm in morning)
  4. Turn on if tempiture under 19 between 1700-2000 (to make sure house is warm in evening)
  5. Alow heating to be manualy turned on (it will be turned on by 2 above if it gets to 19)
  6. Have a way of setting a ā€˜at homeā€™ mode that keeps temp above 19 (this is for weekend) but reset after 4 hours.

Also would love to have a summer and winter mode that just turns on boiler for a houre early morning and around 1700 to ensure we have hot water (I have an old Baxi back boiler and would have to manualy set the controler to water only during saummer but can live with this.

13

Have you read the doc I linked further up?

14

will do. sorry missed that

15

I share the concern about powering the boiler on and off to control temperature. I donā€™t know that particular model, but these things have some internal controls. Theyā€™re designed to take input from a thermostat, but thereā€™s a lot more going on inside.

Again not knowing this particular model, if it has two wires for an external thermostat, itā€™s just a matter of connecting them to some sort of smart switch. Then the HA generic thermostat (or your own home-grown automation, or whatever) can act as the thermostat.

16

If you are going to build your own thermostat you should look at this.

This has been running my heating for a long time now. Easy bit of DIY. Helps if you have a 3D printer.

17

Its a verry old Baxi back boilet. Very basic. It Has a simple dial where you can set two on periods. It has 2 sliders, one for water and one for heating. Both have off, on and twice as settings. Each also have a little tab that enables you to turn on untill the next time thedial turns it off. Its about 30 years old, maybe 40. As I said they are very basic.

Its a Baxi Bermuda https://www.acwilgar.co.uk/Boiler-Manual-PDF/Baxi/BAXI%20BERMUDA%20INSET%202%20BLR%2050-4%20GCNo.44-075-01.pdf

ā€œI share the concern about powering the boiler on and off to control temperature. I donā€™t know that particular model, but these things have some internal controls. Theyā€™re designed to take input from a thermostat, but thereā€™s a lot more going on inside.ā€

There is no thermistat, its a lot more basic than that.

18

I see now. The manual you linked to has a wiring diagram. That is a simple system. Yeah, just switching the line voltage with a smart plug will do the trick. Just set the built-in thermostat higher than youā€™d normally want.

19

Thanks for looking at diagram. Was not totaly sure. Seems to be working well and should save my gas bill and keep the house warm.

20

is any option to swap the on/off. The water floor heating valves are closed at desired temperature,the termostat app is on when heating and off at desiret temp. I have sonoff 4ch and 220V valves. When is my preset temp in room sonoff turn on the valve and close the valve,and when is cold turn off and valve opens. So this is only possible in cooling mode.