Oil or gas-fired boiler for heating fluid such as water has smoke tubes passing between rear and front return chambers before going to outlet flue

摘要

The boiler, using burner (20) preferably fuelled by gas or oil, has a reservoir (10) for the fluid, e.g. water, to be heated containing a combustion chamber (1) and smoke tubes (3) to transmit heat from the combustion gases to the fluid. The smoke tubes are situated between rear (2) and front (5) return chambers, with an outlet tube (8) from the front outlet tube to the boiler flue.