bluelou6 wrote:I have to be careful with turning my pump on full speed with my boilermaker. It actual sucks the bottom of the pot up to the dip tube and stops flowing. Not a problem on any of my other pots.
Silver solder a little nub of SST (or even copper wire) to the end of your dip tube.
As for the OP:
I'm thinking autoneuclation from, as mentioned, the heat.
Example
In your microwave heat water in a pyrex vessel till it boils strongly. Open the door and observe the boiling stop. Sprinkle a bit of salt into the water. Watch it boil furiously for a bit and be glad I didn't tell you to grab it.
All that is happening is the liquid on the edge of boiling is stimulated just that tiny bit and that is sufficient to cause molecular action which heats the water just enough to get a fast boil. It's called autoneuclation.
Jiggling it can do it to.
In the lab people cooking Agar often forget or fail to understand this and get boiling hot sticky agar all over their skin when they reach in too soon after the timer goes off to grab their agar.
So what I think may be happening in your Brewery:
The wort fluid is hot hot hot as it flows from the tube from the BK.
It hits the pump.
The pump agitates it and suddenly it's boiling again.
The steam from the boil blocks the tube from the BK and the bubble has to clear before the pump can pump again because the March pump can not self prime, it needs a gravity flow.
