Hi,
I have a Galahad 240, the rad is at the top blowing out..
The in/out pipes on the rad need to be above the cpu block, if not you could get air bubbles and the coolant won't circulate properly..
I had to reseat the block a couple of times as it need to be dead flat and the fixing being only 2 screws can be a little fiddly to get right..
Also your pump needs to be at 100%, make sure it's plugged into the AIO/WB header..
AMD Ryzen 9 9900x, Asus Prime X 9070, Asus Crosshair X870E Hero, 64gb Kingston DDR5 6000, Samsung 980pro 1tb NVME, Samsung 970 EVO Plus 1tb NVME, DeepCool Mystique 360 AIO, Antec Titanium 1000w.