System for producing heat for domestic hot water or central heating

A system for producing heat for domestic hot water or central heating comprising:

• a heat generator for obtaining heat from a heat source, the heat generator having a generator outlet port and a generator return port;
• a central heating circuit having a heating feed port and a heating return port;
• and
• a tank having an inlet port at a bottom portion of the tank, an upper port and a lower port, the tank containing a fluid which is a heat storing fluid, and the inlet port being configured to feed the heat storing fluid into the tank;
• wherein the heat generator, the central heating circuit, and the tank are fluidly connected in series so as to allow the fluid to flow from the heat generator via at least one of the central heating circuit and the tank back to the heat generator;
• the system further comprising:
• a first three-way valve fluidly connected to the heating feed port and the heating return port and configured to selectively let the fluid bypass, or flow through, the central heating circuit;
• a second three-way valve fluidly connected to the first three-way valve, the generator return port, and the inlet port, and configured to selectively let the fluid bypass, or flow through, the tank via the inlet port;
• and
• a third three-way valve fluidly connected to the upper port, the lower port, and the generator return port, and configured to set a relative proportion by which the fluid flows through the upper port and the lower port, respectively, to the generator return port.