Hydraulic unit for a heating or air-conditioning system

A hydraulic construction unit for a heating facility or air-conditioning facility, the hydraulic construction unit comprising:

• at least one heating circuit return connection
• a first heating circuit feed connection for a heating circuit;
• a heat source outlet fluid conducting connected to the return connection;
• a circulation pump assembly;
• a heat source inlet which is fluid conducting connected to the first feed connection as well as fluid conducting connected with the circulation pump assembly which is arranged in a flow path between the return connection and the heat source outlet or in a flow path between the heat source inlet and the first heating circuit feed connection;
• at least one second heating circuit feed connection for a second heating circuit, wherein the second heating circuit feed connection is fluid conducting connected to the heat source inlet and to the return connection so that a mixture of fluid from the heat source inlet and the return connection can be fed to the second feed connection;
• and
• at least one mixing valve arranged in a first flow path from the heat source inlet to the second heating circuit feed connection and/or in a second flow path from the return connection to the second heating circuit feed connection, the mixing valve being configured to selectively change a mixing ratio between fluid flows in the first and second flow paths to change the temperature at the second feed connection.