From a8b5d1511d9624d925c1089a80c9a98e328e68bd Mon Sep 17 00:00:00 2001
From: mvn23 <schopdiedwaas@gmail.com>
Date: Mon, 30 Jun 2025 20:24:13 +0200
Subject: [PATCH] Populate hvac_modes list in opentherm_gw (#142074)

---
 homeassistant/components/opentherm_gw/climate.py   | 13 ++++++++++++-
 homeassistant/components/opentherm_gw/strings.json |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/opentherm_gw/climate.py b/homeassistant/components/opentherm_gw/climate.py
index 68463e764f2..c7e107b1637 100644
--- a/homeassistant/components/opentherm_gw/climate.py
+++ b/homeassistant/components/opentherm_gw/climate.py
@@ -21,6 +21,7 @@ from homeassistant.components.climate import (
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import ATTR_TEMPERATURE, CONF_ID, UnitOfTemperature
 from homeassistant.core import HomeAssistant, callback
+from homeassistant.exceptions import ServiceValidationError
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
 from homeassistant.helpers.entity_platform import AddConfigEntryEntitiesCallback
 
@@ -30,6 +31,7 @@ from .const import (
     CONF_SET_PRECISION,
     DATA_GATEWAYS,
     DATA_OPENTHERM_GW,
+    DOMAIN,
     THERMOSTAT_DEVICE_DESCRIPTION,
     OpenThermDataSource,
 )
@@ -75,7 +77,7 @@ class OpenThermClimate(OpenThermStatusEntity, ClimateEntity):
         ClimateEntityFeature.TARGET_TEMPERATURE | ClimateEntityFeature.PRESET_MODE
     )
     _attr_temperature_unit = UnitOfTemperature.CELSIUS
-    _attr_hvac_modes = []
+    _attr_hvac_modes = [HVACMode.HEAT]
     _attr_name = None
     _attr_preset_modes = []
     _attr_min_temp = 1
@@ -129,9 +131,11 @@ class OpenThermClimate(OpenThermStatusEntity, ClimateEntity):
         if ch_active and flame_on:
             self._attr_hvac_action = HVACAction.HEATING
             self._attr_hvac_mode = HVACMode.HEAT
+            self._attr_hvac_modes = [HVACMode.HEAT]
         elif cooling_active:
             self._attr_hvac_action = HVACAction.COOLING
             self._attr_hvac_mode = HVACMode.COOL
+            self._attr_hvac_modes = [HVACMode.COOL]
         else:
             self._attr_hvac_action = HVACAction.IDLE
 
@@ -182,6 +186,13 @@ class OpenThermClimate(OpenThermStatusEntity, ClimateEntity):
             return PRESET_AWAY
         return PRESET_NONE
 
+    def set_hvac_mode(self, hvac_mode: HVACMode) -> None:
+        """Set new target hvac mode."""
+        raise ServiceValidationError(
+            translation_domain=DOMAIN,
+            translation_key="change_hvac_mode_not_supported",
+        )
+
     def set_preset_mode(self, preset_mode: str) -> None:
         """Set the preset mode."""
         _LOGGER.warning("Changing preset mode is not supported")
diff --git a/homeassistant/components/opentherm_gw/strings.json b/homeassistant/components/opentherm_gw/strings.json
index 8959e0facf9..f3938c81e7e 100644
--- a/homeassistant/components/opentherm_gw/strings.json
+++ b/homeassistant/components/opentherm_gw/strings.json
@@ -355,6 +355,9 @@
     }
   },
   "exceptions": {
+    "change_hvac_mode_not_supported": {
+      "message": "Changing HVAC mode is not supported."
+    },
     "invalid_gateway_id": {
       "message": "Gateway {gw_id} not found or not loaded!"
     }