. HVAC EQUIPMENT INSTALLATION: OCTOBER 6, 1999 . This is two of a series of three photo files covering the installation of the HVAC equipment by Southwestern Air. Other files: 100499 and 100799. The scaffolding is raised to provide work area for installing the 4 HVAC units. The grating on the pier is removed and an I-beam removed so that the units can be lowered beneith the pier. angle channel (short red pieces) are welded into place which will support the units.