We had a ducted heat pump installed with all new duct work a week ago. The downstairs system has a chemical smell when run which won’t seem to go away. The duct work is insulated metal trunk and supply runs which branches into insulated flex to each supply and return. The mastic was applied to the metal duct work on the inside and outside of the seams. However, Hardcast 1403 tape was used to seal the separate pieces together from the outside as well as seams where flex branches off. The tape was also used to seal all the boot seams and quite heavily in our in-floor pan return (between subfloor and joists, metal and joists, etc.). When I leave the system off for a while and stick  my head in the return I can smell it which makes me think it’s the tape. When I smell the leftover pieces of tape it appears to be a stronger version of the smell. After seeing a similar post on here, we vacated the house for the weekend, cracked the windows and are running the system at high fan speed and with tstat calling for maximum heat.

When I brought this up to the installers they insisted it was oil on the coil that will “burn off” but google searches seem to think that would only take an hour or two. So far we’ve run it for over 24 hours. I’m panicking a bit because there were already numerous issues with the install and this nightmare won’t conclude.

Will this smell go away? Is it safe that they used the tape on the inside, it says it’s zero VOC tape but I have a pregnant wife.