Domestic hot water heating system

摘要

The heating system consists of a gas-fired boiler, with the a controlled gas supply, a secondary heat exchanger through which the output is circulated by a pump, and a storage tank for the hot water supplied by a circulation pump in the secondary circuit of the second heat exchanger. A control unit governs the circulation pumps and the gas valve in response to signals from the temperature sensors. The primary heat exchanger (5) is heated by a gas burner (4), supplied through a valve (2) which may be varied by a drive (34), controlled through the system control unit (18). The heated output water is pumped through a secondary heat exchanger (7) by a circulation pump (10), controlled by (18). The hot water storage tank (14) is fed with cold water through a pipe (24) and hot water is drawn off through an outlet (31). Water from the lower area of the tank is pumped to the upper region through pipes (25,27,29,13) and pump (28) through the secondary of the heat exchanger (12). signals from temperature sensors (20,23,16) cause the control unit (18) to operate the pumps and gas control valve to prevent water at the top of the tank becoming too hot and that at the bottom becoming cold.