| 摘要 |
A gas-fired appliance 74 e.g. a boiler is associated with ventilating apparatus 80 mounted over an air vent 78 in a wall the apparatus 80 having a fan and an air flow sensitive switch, the arrangement being such that when the appliance is switched on e.g. by a time switch 76, the fan is first brought into operation to draw air through the vent in quantities sufficient to activate the air flow sensitive switch which then allows ignition of the gas in the appliance. The vent 78 is a standard size wall air vent. The apparatus 80 may include a thermostatically actuated electric and/or water-to-air heater and a dust or insect filter. The water-to-air heat exchanger may be shaped like a grille and adapted to fit over the air vent. <IMAGE> |
