We just had our furnace serviced (just routine). The only problem the technician found was the float in the humidifier which he replaced. Ever since then there has been an odor that smells kind of like melting plastic?? I have had the company back to check and they couldn't find anything?? My husband can't smell it, but my sense of smell is very acute and it bothers me. Has anyone ever had this happen to them before or have any idea what the problem could be??? Thanks.