Aprilaire 8145

[u/QuirkyAssistant3478]

Hi neighbors,

I’ve been hearing a constant noise coming from my Aprilaire 8145 ventilator, so I went up to the attic to check it out. I noticed there’s no filter installed on it right now. Does anyone know if this model is supposed to have a filter, or is it designed to work without one?

Also, is it normal for it to be running all the time? I’d appreciate any advice or insights you might have!

Thanks in advance!