Hello SRadzins,
We need to know which types of IFC export preset settings you have used to be able to help you.
Did you try to read these ifc files with solibri or other ifc viewer before sending to your HVAC ?
Christophe - FRANCEArchicad Designer and Teacher
Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM
"Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin