Report "Pilot light is difficult to light, once lit, when gas valve turns on, pilot and flame goes out, but the gas continues to flow. I cannot use my heater as long as this problem exists. I have cleaned the Pilot tube and burner unit. I have a feeling that the problem exists in the thermocouple, but the part is not listed as a replacement part. I would be willing to replace the entire burner unit, but need a supplier. Does anyone have an 800 number I can use to order parts?"