Agree. When the TAB opened the return air damper manually to 100% the total air increased to near design. The O/A decreased below design. We do have some margin in the motor to increase the fan RPM but this thing is already outside of the fan curve envelope. The static pressure is below where...
I am in the process of troubleshooting an O/A duct distributing air to four AHUs. The most remote AHU is modulating the return air dampers to give a constant 900CFM of outside air. Due to the return air damper modulating down the total air is low. I am getting a varing consensus of opinion among...