We have had a direct-vent Vermont Castings gas stove for about 5 years now. It has produced a bad smell throughout the house whenever we use it ever since we got it. Originally a contractor did the installation so we got the local dealer to reinstall it completely replacing the piping and the vent. This has not helped the problem. The dealer doesn't know anything else to try. We have over the years run it for long periods of time to try to burn it in. This doesn't seem to help either. I am about to totally replace the unit since it still is not working properly for us. The smell is similar to what we got when we first got the unit but not quite as acrid. We have also had the gas company out with a CO2 detector to make sure it wasn't carbon monoxide that we were smelling. Does anyone have any ideas of anything else we can try before we scrap and replace it?