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May I ask a question? I've just come across a Riello BF3. The problem, the oil does not shut off during the post purge cycle. At first I thought it was the oil valve stem but no. Then I thought it was the post purge timer but that's not it. I tried a new pump thinking the valve was fouled. (the filtration is poor, FB4 from an old tank single pipe to the burner.) I haven't ruled out the stem even though it's fresh out of the box. The reason I say that is even if I remove the solenoid the oil is still delivered though it seems to have a restricted flow. Am I missing something? Any help would be great, Thanks.