I have compacted the grain bed before from pumping too fast. It's really not a big deal, just lost time. Stir the grain bed up again and reset it. What you can get away with will depend on your system and the grist. Installing a vacuum gauge on the outlet of the mash tun would help you see how fast you can pump. Or 2 sight glasses...one with the inlet above the false bottom and one below, then compare the levels while you're recirculating. Rice hulls and malt conditioning will also help you get a higher flow rate before compaction happens.
Fermenting: Helles, Egregious-ish, Barrel Fermented Dreg Lambic, Sacch Trois Helles
Drinking: RIS, Tripel, Tired Hands Style IPA, Carrot Blossom Cedar Mead, Dusseldorf Altbier, Dopplebock, Cider, Rye Berliner Weisse, Sauerkraut Fermented Gose, Lambic, Sacch Trois IPA, Brett Blonde, Kriek, Saison, Sour Blonde
Barrel aged: RIS, Rye Barleywine, Tripel, Wee-Heavy