Hi, I've a VM single family with a gas fireplace. House is about 3 years old. Gas fireplace worked fine last winter and the winter prior. I've used it several times this late fall/winter with no problems. Now, in the past two times its been used (last week and tonite) it will shut itself off after about 20 min. Any ideas what's going on? Anyone else experience this? I have not had it inspected, but I suppose that's what I need to do ... so any recommendations for an inspector that is trustworthy and good? Thanks much!