What could a noxious chemical odor coming from a turned-off convector AC heat unit be if it's not natural gas but smells like the self-cleaning oven smell?
Hi: Wow,,,, this question kinda leaves me hangin on details I need , But! ( it is a bonefide good one ) and I think it deserves at least an attempt on my part ( even though ) I am bit uneasy because of the lack of details I have been presented. Answer simplified,,,, it's probably a step down control transformer or pull in coil of some sort. They give off a really pungit chemical odor when partially shorted or overloaded. Another possibility is,,, A run capacitor or start capacitor on a fan motor or such. And yet another possiblility is, some modification that has been made through either a clean up process or repair or paint and or lubrication that has gone awry. You should have a real pro. come and check this baby out my friend. It's probably not that big of a deal and a good honest service tech. with good test equipment and skills can probably put your concerns at ease really quick! Don't USE it till you KNOW though. Hope this helps you out: Jimiwane