In this episode I touch on make up air units, applications, types and a job I did back in day, where I wired in sail switches to interlocking exhaust fans. Testo 317-3 https://www.testo.com/en-US/testo-317-3/p/0632-3173 Cooling United Support Hub https://www.danfoss.com/en/service-and-support/fix-and-troubleshooting/cooling-support-for-installers-and-wholesalers/?utm_source=influencer&utm_medium=affiliate&utm_campaign=dcs_cooling_united_support_hub&utm_content=HVAC_Know_It_All_Cooling_United_Support_Hub Chinook Filter Cleaner https://www.coolairproducts.net/chinook-1lt/ House Call Pro https://www.housecallpro.com/hvacknowitall https://www.hvacknowitall.com/blogs/blog/244266-make-up-air-units-explained