Patent 7628607 was granted and assigned to Rinnai on December, 2009 by the United States Patent and Trademark Office.
A microcomputer 51 of an electronic circuit unit 50 actuates an electric motor (stepping motor) 20 driving a thermal power control valve of a burner during or just after extinguishment of the burner to displace the thermal power control valve to an opening degree position for ignition. In this way, the delay of the start of an ignition process of the burner for an ignition request can be eliminated to start the ignition process promptly.