I tell people that Janitrol is not a good product and they argue with me. Sorry, but your just one more who will be testimonial to the fact that they are JUNK.
A guy posted last year that, in 5 years he replaced virtually every component in the furnace & still had problems.
Sorry, but I don't have any real good advice. Maybe call around to furnace servicemen & see if any have had good luck with your particular model. Sometines you can get free advice over the phone, but before you let them come out and charge you $50, ask what they think or common symptoms etc.