What a nightmare I am in I previously had an old Thermopride oil furnace. I decided to upgrade to natural gas. If I could go back in time I would shoot myself in the head before I went through with it. I get a new gas line installed and tested. I get the furnace installed, a new direct vent 95% efficient Trane. Minutes after it fires up, I get a terrible headache and can smell a gas smell in the house. The odor is particularly strong at the combustion unit of the furnace. Neither my wife no my son can smell anything. CO detectors all read 0. I call back the installer to complain, and persist, eventually they replace the furnace. The put the new one in and fire it up, I sniff near the combustion unit, no odor. Great, all solved, bad furnace Over the next few days I start to get headaches again, I go down to check out the furnace, and the gas smell is back when I sniff near the combustion unit So now I'm out thousands getting this thing put in, and am going to be out thousands more to switch it to something else, and I'm afraid a new oil furnace will have the same problems (it looks like newer furnaces are built differently than older ones). I asked if I could get my old furnace back and reinstalled, but the scrapyard already junked it. CO detectors have never gone off, the gas line was checked for leaks multiple times and never leaked, it passed the pressure test, the techs put their sensor right in the duckwork and didn't detect any CO. The exhaust pipe direct vents out of the house and is not blocked, and the fresh air intake is also outside the house and not blocked and no anywhere near the exhaust pipe. The odor smells like the smell you get when you turn on a gas grill and it doesn't light right away, that kind of metallic gas scent. It's very faint, just happen to be extremely sensitive to odors. No one else has been able to smell this except me. The scent is only around the combustion chamber of the furnace, and coming out of the heating vents in the house. The heat itself is fine. Any thoughts what this could be? I'm confused because theoretically, the heating parts of the furnace should be a sealed system, if I understand it correctly, the gas flames are heating metal tubes/heat exchanger and the fan blows air over them. Because this is the second furnace they installed they checked the heat exchanger for cracks and didn't find anything. Is this level of odor normal for new HE furnaces and and I just screwed now? Any help would be appreciated, I am at my wits end. I am halting all other work on the gas conversion of my hot water heater and am keeping my oil tank in case I decide to go back to an oil furnace, but I'm terrified that will cause the same problems.

I have a natural gas Tappan direct vent furnace located in the attic. I have never had issues before. Now that heating weather is here, I noticed that the air handler does not move air when the programmable thermostat calls for heat. I did some looking around. When the stat calls for heat, I can feel heat at the furnace. I can get the fan to run ONLY when the thermostat does not call for heat. For example, when the heat is off, I can set the fan to on and it will run. When I turn the heat on and turn up the thermostat, the fan stops. Also the fan won't run in auto mode. Any thoughts would be welcome. If this is a thermostat issue I'd be happy to replace it.