On/off control of the CH Boiler within the integration

[rhlgithubrhl]

This may all be old stuff but I could not find anything about it so I seek information and advice please..
I have used the excellent integration and UI but am still a bit unsighted on how the CH boiler is turned on and off, if indeed it controlled at all. I have several Sonoff TRVs all working well using separate thermostats that are better placed in the respective rooms. What I do not understand is that if there is no demand from any TRV how is the boiler turned off? And, if only one TRV demands heat how is the boiler turned on. I can easily use a CH Boiler on/off smart switch if this integration uses it.

[arthurdent2095]

I found that if you add an automation in HA with multiple triggers, they are OR'd. So I have an automation across all my valves to turn the boiler ON. If any one of them goes to heating then the relay comes on.

And another to turn them OFF, but the second uses an extra check condition to ensure all the valves are off ( AND across all the entities ) so the second automation is twice as much config.

I first piloted it with a lamp so that I could figure out which devices and entities worked best, happy with it now BUT I am wondering how to add in some small hysteresis.

One thing - I am using the demand from the underlying valves to trigger my boiler, not BT. I found that they are not always open when BT wants them to be. And I'd rather not have the pump fighting against closed valves.

Note: If your boiler uses on/off this is fine. If it uses open therm and has a variable input I feel certain we will need a voltage encoder, I am sure that means in future we'll need to build one of those and have a smarter automation e.g. that knows how many rads are open and increases the demand.

I am currently wondering how to get all the 240v signals from the heating setup into HA, including all the valve head signals, hot water thermostat and so on. Haven't come across anything ideal yet for this.

[rhlgithubrhl]

I agree on the hysteresis issue as my system seems to cycle too quickly. I also note the HA Automation logical OR of triggers. In my use case that is not an option as I have named triggers where some have different conditions and actions. I guess it is part of the pros and cons of using a single routine to do multiple tasks. I use a 1 bit optocoupler to sense 240v and send status to HA using a D1 mini 8266 board, it works well but hardware would need to repeated at each 240v monitor point unless they are co-located in which case the simple D1 mini with an I2C board will do for most use cases. I also use an HA template to turn the boiler on if any TRV demands heat and off if no TRV demands heat.

[rhlgithubrhl]

Further to my last post, here is my Automation trigger template to turn boiler on for any heat demand:

{% set BTStats = [
states.climate.lounge_better_thermostat,
states.climate.dining_better_thermostat,
states.climate.spareroom_better_thermostat,
states.climate.dormer_better_thermostat,
states.climate.bathroom_better_thermostat,
] %}
{% set climates = namespace(under=[]) %}
{% for BTStat in BTStats %}
{% if BTStat.attributes.current_temperature < BTStat.attributes.temperature %}
{% set climates.under = climates.under + [ BTStat.entity_id ] %}
{% endif %}
{% endfor %}
{{ climates.under | length > 0 }}

And for no demand:

{% set BTStats = [
states.climate.lounge_better_thermostat,
states.climate.dining_better_thermostat,
states.climate.spareroom_better_thermostat,
states.climate.dormer_better_thermostat,
states.climate.bathroom_better_thermostat,
] %}
{% set climates = namespace(at_target=[]) %}
{% for BTStat in BTStats %}
{% if BTStat.attributes.current_temperature >= BTStat.attributes.temperature %}
{% set climates.at_target = climates.at_target + [ BTStat.entity_id ] %}
{% endif %}
{% endfor %}
{{ climates.at_target | length == BTStats | length }}

I then named the triggers and conditionally use them to turn the main boiler on or off using the switch service. I could probably have simplified this further as each template is essentially the complement of the other.

[arthurdent2095]

PS. I am using a dry contact relay MHCOZY for this which also is a zigbee router. I have 3 spare relay outputs as a result and might use one for the hot water ; worth it if I can make the hot water a bit smarter somehow.

[arthurdent2095]

alias: CH demand ON
description: Any valve will turn on the CH on the boiler
trigger:

• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action
    to: heating
• platform: state
  entity_id:
  • sensor.trvzb_office_hvac_action_5
    to: heating
• platform: state
  entity_id:
  • sensor.trvzb_kitchen_1_hvac_action_3
    to: heating
• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action_2
    to: heating
• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action_3
    to: heating
• platform: state
  entity_id:
  • sensor.trvzb_bedroom_hvac_action_2
    to: heating
    condition: []
    action:
• type: turn_on
  device_id: afe93c1cad4a7f139b653b0aa045af01
  entity_id: 59ab8960839a85ba30c6771ba8ffac96
  domain: light
  mode: single

alias: CH demand OFF
description: Checks no valves are still demanding heat and if not switches off boiler
trigger:

• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action
    to: idle
• platform: state
  entity_id:
  • sensor.trvzb_office_hvac_action_5
    to: idle
• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action_3
    to: idle
• platform: state
  entity_id:
  • sensor.sonoff_trvzb_hvac_action_2
    to: idle
• platform: state
  entity_id:
  • sensor.trvzb_kitchen_1_hvac_action_3
    to: idle
• platform: state
  entity_id:
  • sensor.trvzb_bedroom_hvac_action_2
    to: idle
    condition:
• condition: state
  entity_id: sensor.sonoff_trvzb_hvac_action
  state: idle
• condition: state
  entity_id: sensor.trvzb_office_hvac_action_5
  state: idle
• condition: state
  entity_id: sensor.trvzb_kitchen_1_hvac_action_3
  state: idle
• condition: state
  entity_id: sensor.sonoff_trvzb_hvac_action_2
  state: idle
• condition: state
  entity_id: sensor.sonoff_trvzb_hvac_action_3
  state: idle
• condition: state
  entity_id: sensor.trvzb_bedroom_hvac_action_2
  state: idle
• condition: device
  type: is_on
  device_id: afe93c1cad4a7f139b653b0aa045af01
  entity_id: 59ab8960839a85ba30c6771ba8ffac96
  domain: light
  action:
• type: turn_off
  device_id: afe93c1cad4a7f139b653b0aa045af01
  entity_id: 59ab8960839a85ba30c6771ba8ffac96
  domain: light
  mode: single