Assured Comfort Heating, Air & Plumbing worked on my furnace for me. Their employees were very nice, and very professional. They told me that my chimney was precipitating bits of metal into my furnace, and that is why it was acting up. So, I had the chimney redone. Afterwards, the furnace was still acting up, so they came out one more time and whatever they did, took care of the problem and it has been running fine ever since.