Specifications include, but are not limited to: 1) Supply and install (2) 30 HP plug type return air fans. Each return air fan shall move 27,800 cfm with a total static pressure of 3.0 in. wc. 2) Cut a 38” x72” opening in the side of the return air plenum of both units to allow for the relief air to reach the relief air duct on the end of the building. 3) Cut the necessary hole in the floor of the return air section to install an automatic return air damper in the floor of the return fan section to communicate with the return air plenum sized for a maximum airflow speed of 1500 fpm. 4) Supply and install an automatic relief air damper in the relief air duct to allow for relief exhaust. 5) Supply and install the electrical controls, Variable Frequency Drives for the return air fan blower motors, and any other necessary electrical wiring or accessories to facilitate the added return air fans. 6) The unit controls shall be set up to allow 0-100% outside air when the modifications are complete. See the attached original air handler plans for reference.
