Heating unit

A heating method comprising:

• providing a heating apparatus comprising:
• two heating circuits including a first heating circuit for room heating and a second heating circuit for domestic water heating;
• a primary heat exchanger for introducing heat into the heating circuits;
• at least one secondary heat exchanger for the domestic water heating;
• another secondary heat exchanger for the room heating;
• a circulation pump;
• a switch-over valve which hydraulically integrates the primary heat exchanger into the first or into the second heating circuit wherein the heating circuit for the domestic water heating, on operation of the heating circuit for room heating, forms a bypass conduit for the primary heat exchanger, and the switch-over valve forms the bypass valve;
• a detection means for detecting the necessity of a bypass function the detection means being provided in the region of the primary heat exchanger;
• and
• a control which on detecting the necessity of the bypass function, activates the switch-over valve for the conduit connection to the heating circuit for domestic water heating to define a bypass state of the switch-over valve, wherein a bypass fluid flow path is formed when the switch-over valve is in the bypass state, the bypass fluid flow path comprising the second heating circuit, the switch-over valve, the circulation pump and the primary heat exchanger, wherein fluid moves along the bypass fluid flow path when the switch-over valve is in the bypass state, wherein no bypass valve is integrated in the switch-over valve, wherein the switch-over valve is controlled such that the switch over valve operates as the bypass valve, wherein an outlet line of the another secondary heat exchanger is connected to the at least one secondary heat exchanger for the domestic water heating in the bypass state.

A heating apparatus comprising:

• a plurality of heating circuits, the plurality of heating circuits comprising a first heating circuit for room heating and a second heating circuit for domestic water heating;
• a primary heat exchanger;
• a secondary domestic water heat exchanger for the domestic water heating;
• a secondary room heating heat exchanger for the room heating, the secondary room heating heat exchanger comprising an outlet;
• an outlet line connected to the outlet of the secondary room heating heat exchanger;
• a circulation pump;
• a switch-over valve which hydraulically integrates the primary heat exchanger into the first heating circuit or into the second heating circuit, wherein the heating circuit for the domestic water heating, on operation of the heating circuit for room heating, forms a bypass conduit for the primary heat exchanger, the switch-over valve comprising a bypass position, the outlet line being in fluid communication with the secondary domestic water heat exchanger when the switch-over valve is in the bypass position.