Combination control with high/low pilot gas flow

In a combination control including a housing having a gas inlet, a main burner gas outlet, a pilot burner gas outlet, a first flow passage including first and second serially connected chambers interconnecting said gas inlet to said main burner gas outlet, and a second flow passage interconnecting said first chamber to said pilot burner gas outlet;

• a thermostatically controlled redundant valve in said first flow passage between said first and second chambers;
• a differential pressure operated main valve in said first flow passage between said second chamber and said main burner gas outlet;
• and adjustable flow restrictor means in said second flow passage for adjusting a high pilot supply of gas therethrough to produce a pilot burner flame of a selected large ignition size for ignition purposes;
• the improvement comprising:
• parallel first and second inlet branch passageways in said second flow passage upstream of said pilot flow adjustment means;
• said first inlet branch passageway communicating with said first chamber and including flow restriction means for supplying a restricted low pilot supply of gas to said pilot burner gas outlet to produce a pilot burner flame of a small standby size when said redundant valve is closed;
• said second inlet branch passageway communicating with said second chamber and bypassing said first inlet branch passageway for supplying an increased high pilot supply of gas to said pilot burner gas outlet to produce a pilot burner flame of a large ignition size when said redundant valve is open;
• and check valve means in said second inlet branch passageway for blocking gas flow from said first inlet branch passageway to said second chamber through said second inlet branch passageway when said redundant valve is closed.