The fans on our fireplace insert don't seem to be pushing much air. There are two of them, mounted behind a grill under the firebox. They are supposed to move air through another grill mounted above the firebox. I took the fans out last year and cleaned all the dust off them. They seemed to work a little better, but that could be wishfull thinking. Another variable: The AC power to the fans runs through a light dimmer switch so that fan speed can be controlled. I'm not sure about how motors work with power from such a switch. The insert was in the house when we bought it, so I don't know the manufacturer or have any information on it. Is it possible to buy generic replacement fans for inserts? Any suggestions?