I HAVE A BAXI SOLO WM 30/ 4RS BOILER. PROBLEM IS PILOT LIGHT AND MAIN FLAME GOES OUT. SYMPTOMS ARE AS FOLLOWS. TURN OFF THE GAS KNOB. LIGHT THE PILOT LAMP MANUALY, STAYS ON, TURN THE ABOVE GAS KNOB TO MEDIUM, THE MAIN BURNER LIGHTS NICELY, BUT AFTER A FEW SECONDS (APPROX. 15 TO 20 SECONDS) THE MAIN ...