1. Mechanical work includes: a. Demolish the existing supply and return fan inlet cones/dampers. b. Replace the existing, large supply and return fans with a fan array configuration that includes a greater quantity of smaller direct drive fans with electronically commutated motors (ECMs). The ECMs are installed with an electronic control driver instead of variable frequency drives (VFDs). c. Perform functional cleaning of the major components of the AHU and provide commissioning services after all retrofit work is completed. Test and balance fan air flows. 2. Electrical work includes: a. Reuse or demolish feeders to existing supply and return fans that are being replaced. b. Provide feeders and associated overcurrent protection for new mechanical equipment. c. Install a harmonic filter at the electronic control driver to protect the AHU, as well as the other equipment fed from the associated electrical switchgear. 3. Structural work includes: a. Restrain new fan array system inside AHU-3
