| 摘要 |
<p>The central heating burner-fired boiler is conventional with temp. sensor controlled firing and a shut off valve in the uptake. This valve comprises a ball (25) seating in the circular inlet (26) to a cylindrical chamber (23). The ball is light enough for the (blown) gas flow to dislodge it, onto a ledge (31) of slightly less than ball-dia. width sloping gently inwards. The control system embodies a pressure-sensor (29, 30) downstream of the valve which delays burner light up until the thermostat (22) operated blower (21) has built up the necessary pressure.</p> |
