Hello I am new to brewing and made my own single teir system with two pumps. When I transfer the hot liquid from the mash to the boil kettle the liquid quits coming out of the valve and the mash is super sealed when u put a spoon in the coolier. Is that due to the pumps sucking the mash down tight so no liquid can pass. The only way I have found to fix the problem is to dig a hole in the mash with the spoon to let the liquid through. Any help would be greatly appreciated.