[Rotex HPSU 508] Help with thermostat relay connection

[philipgo]

Hello,

I have a Rotex HPSU 508 Compact which I monitor with ESPAltherma. Now I would like to connect a thermostat relay but have some questions.

This is the current situation with bridge in place, no room thermostat:

This is what the manual says about connecting a room thermostat:

I would like to connect one/two? relays to emulate the function of the Rotex "RKRTW" room thermostat.

Questions:

• How can I define a second ("cooling") thermostat relay in ESPAltherma? As far as I understand, the feature is not yet implemented
• If I work with only one relay for heating, how can I activate cooling in summer?
• What do I do with the existing bridge between RT N and RT C if I only use one relay for heating?

Thank you!

[philipgo]

I now built a second device using an M5Stack Stamp C3U and two M5 Mini 3A Relay Units (U023) and programmed it using ESPHome. For me this has the advantage that I can connect the heating to "normally closed" and cooling to "normally open" so that if the device fails, heating will be activated. I also implemented a logic that prevents that both switches are activated at the same time.

Would love to see such a solution integrated in ESPAltherma.

In case anyone is also looking for a solution, this is the ESPHome Code I used:

esphome:
  name: esp32-c3u-thermostat-rotex
  friendly_name: esp32-c3u-thermostat-rotex

esp32:
  board: esp32-c3-devkitm-1
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "xyz"

ota:
  - platform: esphome
    password: "xyz2"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

switch:
  - platform: gpio
    name: "Relais 1: Heizanforderung RT (NC)"
    pin: GPIO1
    id: heizanforderung
    inverted: True
    on_turn_on: 
      then:
        - switch.turn_off: kuehlanforderung
  - platform: gpio
    name: "Relais 2: Kühl-Anforderung RT (NO)"
    pin: GPIO19
    inverted: False
    id: kuehlanforderung
    on_turn_on: 
      then:
        - switch.turn_off: heizanforderung