diff --git a/lib/geo_therminator/pump_api/device/api.ex b/lib/geo_therminator/pump_api/device/api.ex
index 665dd35..e4377c9 100644
--- a/lib/geo_therminator/pump_api/device/api.ex
+++ b/lib/geo_therminator/pump_api/device/api.ex
@@ -103,7 +103,9 @@ defmodule GeoTherminator.PumpAPI.Device.API do
       end)
 
     priority_register = find_register(registers, "REG_OPERATIONAL_STATUS_PRIO1")
-    priority_register_fallback = find_register(registers, "REG_OPERATIONMODE")
+
+    priority_register_fallback =
+      find_register(registers, "REG_OPERATIONAL_STATUS_PRIORITY_BITMASK")
 
     {mapping, register} =
       if not is_nil(priority_register) do