Combined water boiler and warm air heater - has air pre-heaters which prevent condensation in flue

摘要

The water and air heater comprises a burner (9), heating the central heating water via a heat exchanger (6). The hot gases then pass through a perforated screen (17) and over a heat exchanger (26), before exhausting up the exhaust flue (30). The heat in the exchanger is transferred to a coil (41) installed around the flue. Fresh air is admitted through the double skin (34) of the flue and passes over the upper heat exchanger (41) before discharging into the room. The interconnected heat exchangers ensure that the gases entering the flue (30) are at a lower temperature than the entering air (34).