Heat Pumps and Electric Heating - Pipes making loud noise.. Water Source HP

I have a water source heat pump in my house... I have been here about 10 years. This unit is a 5 ton and is 4 years old.
The water comes from a well and pumps into my pond.
Wife has noticed that some water has been spouting air pockets sometimes..

Last night about 4:30am I awoke with a loud loud sound coming from my closet off of the bath. I went in there and it was the pipes under the floor banging on the floor. It would make some noise and then stop
This does not do this all of the time. I might do it 1 min and then stop.. Usually when the heat comes on.

I'm thinking it must be AIR POCKET maybe a pipe come a loose from the joist? I guess I better wrap up and go under there.
The trap door opening is at the other end of the house were the Heat Pump is.. I got to sliver like a rat in the cold.

I did cut off the water from the outside well. Went back in open the faucets let the water drain.. I then cut the water on and let run for 15 min.. I did hear some water spouting.

I have never had this happen.. My unit works fine.. The actual unit is on the opposite end of the house. I walked to that end and I can hear noise even when the heat is not running.
My house is 3,800 sq feet I have a Trane 5 tone Water Source. I have a well. I have 2 ton heat pump up stairs..

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Thanks
David
Tennessee

I assume from your post that you have a water to water heat pump. Sounds to me that your automatic water fill is not working correctly for the inside loop. This works just like any other hotwater baseboard heat automatic fill system. You should have a pressure gauge on the inside loop see if it fluctuates when you hear the banging. My automatic fill has a manual position - I operate this at least once a year incase there sediment or other contamination build up. You may have to drain a little water to add some. You also need to verify if your system had any antifreeze in it - mine does not. This will require additional steps to reset that mix level.

Wife has noticed that some water has been spouting air pockets sometimes..
If this is the same well for the heat pump. Could be pump drains well down some times??? Is pump pipe in well iron?? You could have electrolysis pin holes in the pipe. Lets air in .
If water is hard there. Is heat pumps heat exchanger clean ??