I have a VAV AHU with a economizer which is schedule with an "On" point of 20 Btu/lb. This AHU also has a relief fan that is activated once the AHU goes into economizer mode. How do I properly add and schedule this relief fan operation? Thanks for your help.
Just pick a fan type that you are not currently using in the applicable system. I think the auxiliary fan would be best - but you might need to test a few fan types (the ventilation fan MIGHT work).
Then, set that fan up (as you normally would - with the proper static and power - etc).
See the attached Image