Heating apparatus

A heating apparatus comprising:

• a tank, the tank having a tank inlet, a tank outlet, a heat exchanger inlet and heat exchanger outlet;
• a heat exchanger located in the tank, the heat exchanger comprising a hollow body having a mouth coupled to the heat exchanger inlet and a flue outlet coupled to the heat exchanger outlet;
• a burner device, the burner device having:
• an air intake;
• a burner head including an ignition device;
• a gas injection;
• and
• a burner body providing a fluid flow channel between said air intake and said burner head, wherein said gas injector is configured to inject combustible gas into said fluid flow channel such that said burner body supplies a mixture of combustible gas and air to the burner head in use, and wherein said burner body is located outside of said tank and said burner head, including said ignition device, is located in the mouth inside the hollow body;
• and
• a plurality of pipes extending transversely through the body across the fluid path between the mouth and the flue outlet, the pipes being open to the interior of the tank so that in use they are filled by the contents of the tank, and the pipes defining on one side an internal body region that narrows in a direction from the mouth towards the opposite end of the body, and an internal body region on the other side that widens in a direction from the mouth towards the opposite end of the body.