Summary: Increase connections for liquiducts, get better waterproof pipes or add more tesseracts sending.
Liquiducts don't work based on their volume, but each connection has a transfer limit of 160mb/t. So if you have 10 connections on your boiler, but only 1 to your tesseract, you'll output 160mb from your tesseract on the other side. With boilers, also note that they will output directly to a tesseract, so I personally have found it's best to have the tesseract touching the boiler, and then have four tesseract connections on the boiler and tesseract.
With tesseracts, they will output any volume you put into them, distributed across the receiving tesseracts and the faces. So their throughput is no problem
Actually i found that each (powered) connection transfers 100 mB/t. at least thats what the power converter block is telling me. ca waterproof pipes have higher throughput rates than that? Whats the limit with those?