We recently purchased a home with an old (installed 1989 per previous owner) Wolf 36" residential oven with range, both gas. The range works perfectly. But when we first moved in, we couldn't get the oven to start. We finally found a repairman who got it running. Now, when I turn it on, it clicks until the pilot light ignites. Then it clings and clangs while it attempts to actually heat the oven. I don't know what the part where the flames actually come out to heat the oven is called, but basically, it lights that part for a moment, then that part goes out. Then it lights it again. Then that part goes out. And so on and so forth for several minutes. After a while, it stays on and actually heats the oven. So, from one point of view, it's working fine. I can bake in it. But it makes lots of noise as it goes through this process, and the on-and-off thing makes me worried. I can't find the serial number and I have no instruction manual. What I would like to know is, is this dangerous? Normal? Any advice welcome. . .