Boiling with Homeassistant

In some home fun, today I committed this minor atrocity:

And you might rightfully ask, "but why?". And that takes a little bit of explanation.

You see, that's a blower fan for a kickboard radiator in my kitchen. When we remodeled the kitchen in the way back days, we removed a big radiator against the wall in order to create room for a door to the back porch. So to compensate, we stuffed a small radiator with a blower on it into the kickboard of the kitchen cabinets. Clever solution, right?

Except that some idiot (that'd be me) realized he could reprogram his boiler for drastically improved comfort and efficiency. The factory "outdoor reset curve" (a silly way of saying "how hot the boiler heats the water to based on the outside temperature") was very aggressive. My new one ... is not. At 37F outside right now, the boiler is trying to heat the circulating water to 115F, which is a tad more than is needed to keep the house at 67F. The radiators are (almost) always safe to touch unless it's below 0F outside. The boiler operates within its condensing region, so it operates more efficienctly. Big win.

Except that the kickboard blower only turns on when the water temperature is over 120F. Which it usually isn't.

So my kitchen is cold.

And my family is grumpy.

And my feet get cold while making my morning espresso.

Nobody likes this situation. Except it's nice everywhere else in the house and nicer paying my gas bill.

The kickboard circuit looks like this:

That SPDT (single pole, double throw) is a switch on the front that lets you, the user, select between off / on-low / on-high. The circle on the right is an aquastat - a thermostat measuring the temperature of the water in the pipe, hardcoded to activate at 120F and turn off at about 105F. That little circle is my enemy.

Now a normal person would call up a supply house and buy the beacon-morris low temperature aquastat for about $22 and probably be done with it. But I'm an idiot. Also an idiot who knows how hot his water temperature gets. The low-temp aquastat still doesn't turn on until 110F, and I know that as I write this, at 37F outside, the hot water leaving my boiler is at 115 and the water re-entering it is at 106, and with the poor routing of my heating system (my house is about 97 years old), the aquastat is unlikely to turn on until it gets colder outside.

My solution was to add a parallel bypass across the aquastat like this:

And fortunately, I ripped my Nest thermostats out a few weeks ago and replaced them with Homeassistant-integrated z-wave thermostats, because some idiot PM at Google decided to destroy the functionality of my perfectly working thermostats, guaranteeing that I will never again purchase a Nest product, but I digress.

So I integrated the wifi (matter over wifi) switch with Homeassistant and added this little rule, which says "if the thermostat is turning the heat on, turn on the blower. If the thermostat turns off, wait 1 minute and then turn the blower off."

alias: kitchen radiator sync with heating
description: syncs plug when thermostat starts or stops heating
triggers:
  - trigger: state
    entity_id: climate.t6_pro_z_wave_programmable_thermostat_2
    attribute: hvac_action
conditions: []
actions:
  - if:
      - condition: state
        entity_id: climate.t6_pro_z_wave_programmable_thermostat_2
        attribute: hvac_action
        state: heating
    then:
      - action: switch.turn_on
        target:
          entity_id: switch.mini_smart_wi_fi_plug
        data: {}
    else:
      - delay:
          hours: 0
          minutes: 1
          seconds: 0
          milliseconds: 0
      - action: switch.turn_off
        target:
          entity_id: switch.mini_smart_wi_fi_plug
        data: {}
mode: single

And now the temperature measured somewhere in the middle of that room is about 1 degree F warmer:

And my feet are cozy standing at the espresso machine, thanks to some new thermostats, a cheap wi-fi switch, and homeassistant.