Thank you for the response. The "redundant" fans that I am asking questions about are essentially the fresh air fans. They pull a combination of fresh air and return air to the space. The return fans pull air out to exhaust or recirculate it. There is an exhaust damper, a return/mixed air...
We have a new AHU installed for a Compounding Pharmacy. The unit has two return fans and two supply fans. They are installed in parallel and are powered by VFDs. In the event of one fan failing, the other fan is supposed to speed up to maintain static pressure in the clean environment. This...