| 摘要 |
<p>A burner (2) heats the central-heating boiler (1) directly. Hot water is continuously available (11) from a boiler heat-exchanger (7), via a small (under 20 1) cylinder (10). If its measured (17) flow exceeds a set value, a two-way valve (5) diverts the radiator circuit (4,3) through a by-pass (12), and, in summer, the burner lights to heat the cylinder make-up water, temperature-regulated at the boiler (15). During idle periods, cylinder temperature is maintained by a local thermostat (16), similarly activating the burner and by-pass. An indirect coil (13) in the latter - opt., a small electric heater - transfers the heat required. The burner does not light for brief or low-volume demands, through repeated draw-offs will initiate reheating as cylinder temperature falls.</p> |
