I’ve seen that model in action, no humming. I have heard certain models can be pronounced while others are quiet. As mentioned a fatigued unit can also be a contributing factor.
If mounted in the basement you should be good on the noises if any are observed.
Where did you get replacement seals? USUALLY, they are the same seal as a house toilet supply hose, I’ve found myself over the years purchasing a hose just to take the seal out for a leak here or there.