Grundfos Pump Teardown - What Caused It To Fail

Grundfos Pump Teardown - What Caused It To Fail. I have 2 Grundfos pumps from the boiler system I just had replaced. Both were still working. One sounded perfect, the other had a little bit of a rattling sound to it. Let's tear them down and see what happened to them and what they look like. I got dirt and a small amount of gravel into my system that caused my heat exchanger to fail. What kind of damage, if any, did it to to these pumps?