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 7 3700x, Asus Tuf Gaming RX 6700 XT, Asus TUF Gaming x570 Plus, 32gb G.Skill TZ neo 3600mhz, Samsung 980pro 1tb NVME, Samsung 970 EVO Plus 1tb NVME, Lian Li Galahad AIO 240mm, Antec Titanium 1kw.