Water heating apparatus, especially for pools

摘要

A water heater for heating water includes a burner assembly (54) for generating a flow of hot gas. The burner assembly (54) includes a gas burner (52) and means (64) adjustable to determine a heat output of the burner assembly (54). The water heater further includes a heat exchanger assembly (20) for transferring heat from gas to water flowing therein. The heat exchanger assembly (20) has a higher temperature zone (110) and a lower temperature zone (100). The water heater is arranged to convey the flow of hot gas to the higher temperature zone (110) and in turn to the lower temperature zone (100). The water heater further includes ducting (22, 23) to conduct said flowing water to and from said heat exchanger assembly (20), means (40) to monitor the temperature of the hot gas intermediate the higher temperature zone (110) and the lower temperature zone (100), and control means (70) responsive to the temperature monitoring means (40) to modulate the heat output of the burner assembly (54) whereby to maintain the monitored temperature within a predetermined range so as to substantially prevent or minimise condensation of vapour from the hot gas in the higher temperature zone (110). There is also disclosed a modular heat exchanger apparatus (20) including like headers (34) for redirecting fluid within respective modules (24) and for interconnecting modules (24). There is also disclosed a water heater having a condensate duct (84) to direct condensate into the water for chemically treating the water.