Question: I have a non vented Appalachian gas insert which was installed in 1994. This season it is emitting an unpleasant odor. The odor is more pronounced when the stove is off but the pilot light is lit. I have turned the pilot light off and the odor is dissipating, but I don't know what causes it. I would appreciate any information that you can provide so that I may eliminate this problem and enjoy my stove this winter. Thank you. Answer: You did not mention if it is natural gas or LP. If it is LP, then this could be the problem...your tank could be low...and also different batches of LP can have different smells. Have you had the unit serviced and tested? These burners and ports should be cleaned and inspected. A professional would have a meter which would help indicate improper combustion.