| 摘要 |
Two burners (28,29) of different outputs discharge into a combustion chamber (2) so that the exhaust gas flows through a grate-type heat exchanger (36) where a heat carrier medium (water) in passages (38) is heated. A blower (10) feeds both burners via respective conduits (15,16) of which the conduit (16) leading to the larger burner has a valve (21) opened when the larger burner is switched on responsively to a drop in the outlet temperature in a conduit (43). A 3-port valve (8) distributes the heated water, pumped by a circulation pump (7), to a heat exchanger (5) wherein a domestic water supply is heated and to a conduit (47) leading to a central heating system, the retaining water being passed from return conduits (48,49 and 42) through jackets (41) of the burners before it again reaches the grid-type heat exchanger (36). <IMAGE> |
