Adjustable restrictor for burner

A flow control device for an appliance including a burner and a blower for delivering a pre-mixed mixture of air and gas to the burner, comprising:

• a flange defining an opening through which the pre-mixed mixture of air and gas flows from an outlet of the blower to the burner;
• a damper plate provided in the opening downstream of the blower for controlling the flow of the pre-mixed mixture through the opening to increase a static pressure at the outlet of the blower during ignition of the burner;
• a shaft connected to the damper plate and extending through first and second passages in the flange on opposite sides of the opening;
• and
• a bushing received in the first passage for rotatably supporting the shaft to allow the shaft to rotate relative to the opening.

A system for an appliance comprising:

• a burner for providing heated combustion products to the appliance;
• a blower having an outlet for supplying the burner with a pre-mixed mixture of gas and air;
• and
• an adjustable damper plate positioned downstream of the blower for controlling the flow of the pre-mixed mixture from the blower to the burner, the adjustable damper plate having a first condition during ignition of the burner for increasing the static pressure at the blower outlet and a second condition in response to flame proving for increasing the flow of the pre-mixed mixture to the burner relative to the first condition.