I have a FirstCo 36hbxb-hw in the attic of my new house, and I noticed a whistling noise coming from it. It looks like there are two uncapped ports which are blowing air out into the attic. They're right next to the filter -- the two ports on the right of the horizontal or bottom of the vertical install in these pictures -- https://www.firstco.com/documents/ProductDocuments/hbxb-hw1117.pdf . Should they be capped? I didn't want to cap them without asking, in case they're for pressure release or something.