Richmond 50 gallon gas Integra system

by Don Hall
(DeWitt Iowa)

Pilot won't stay lit. Removed glass inspection cover still no help. Removed burner, finally got enough air flow to keep burner lit. When I try to reassemble pilot goes back out. Burner ignites and stays lit for approximately 10 seconds. The model is a Richmond 50 gallon gas Integra system. Model 12G50=40F1 509465. What can I do to get more air flow to keep it lit? Is there a sensor that needs replaced or something need cleaned? I have had this unit less than 7 years. It has a 12 year warranty.