| 摘要 |
<p>An opening (14) is formed in a wall of the combustion chamber of a balanced flue heating appliance and a closure member (13) is provided for selectively closing the opening. A lever (19) is provided for moving the closure member (13) out of its closed position and a detent formation (26) is engaged by the lever (19) for maintaining the closure member (13) in an open position in which, during use of the heating appliance, the efficiency of the heating appliance is reduced substantially as compared to the efficiency obtained when the closure member (13) is in its closed position. <IMAGE></p> |
