Patent ID: 7568908

Claim:
A control system for a direct fire gas burner comprising: a modulating valve for controlling gas output to the burner; a control in electrical communication with the burner and with said modulating valve; said control providing a low fire start gas condition of the burner above a minimum firing rate as said control interrupts electrical power to said modulating valve therein adjusting the flow of gas attaining a low fire start; one of a space temperature selector in electrical communication with said valve and said control and a discharge temperature sensor in electrical communication with said valve and said control; and, a simulated resistance circuit within said control capable of driving the modulating valve to an open setting in response to a resistance setting; the simulated resistance circuit comprising: a first bypass circuit which bypasses said space temperature selector, said first bypass circuit including contacts to selectively open and close said first bypass circuit; and, a second bypass circuit which bypasses said discharge temperature sensor; said second bypass circuit including contacts to selectively open and close said second bypass circuit.