diff --git a/src/evohomeasync2/schema/const.py b/src/evohomeasync2/schema/const.py
index ceff8469..76707b32 100644
--- a/src/evohomeasync2/schema/const.py
+++ b/src/evohomeasync2/schema/const.py
@@ -144,7 +144,6 @@
 SZ_DURATION: Final = "Duration"
 SZ_HEATING_ZONE: Final = "HeatingZone"
 SZ_PERIOD: Final = "Period"
-SZ_THERMOSTAT: Final = "Thermostat"
 SZ_UNKNOWN: Final = "Unknown"
 
 
@@ -243,9 +242,6 @@ class ZoneMode(StrEnum):
     VACATION_HOLD: Final = SZ_VACATION_HOLD  # not evohome (VisionProWifiRetail)
 
 
-SZ_UNKNOWN: Final = "Unknown"
-
-
 @verify(EnumCheck.UNIQUE)
 class ZoneModelType(StrEnum):
     FOCUS_PRO_WIFI_RETAIL: Final = "FocusProWifiRetail"