plastic inside polymer press heat up to the melting point

Addendum : Once disabled, the petroleum and steam inside the polymer press cool down (steam get even far lower than 96.4 °C)

But ...

The carbon dioxide keep it's temperature. :-/

Seems about right. You didn't explicitly say what you think is wrong. You implied the building should take damage and CO2 doesn't cool down. Just give it time. The building is well below it's overheat temperature (69.1°C vs 125°C), it will only take damage if it's over that temperature. And CO2 has quite low thermal conductivity.

As for the elements to not transition to solids/liquids/gases; elements bottled or while stored in most buildings do not allow element transitions. This comes up very rarely and probably saves a lot of performance (not needing to check every pickupable/building storages). It would also be pointless, nowhere is defined that buildings must take damage form this. Note that buildings can hold any kind of element (solid/liquid/gas) while pipes only hold one type.