AC Handler Keeps Leaking After Multiple Repairs (Geothermal unit)

Question

I first want to start out by saying I am not a handy man kinda guy. My ac has broken every weekend for the past 2 months. The majority of the breakage is constant leaking from the area I will go over below. After 3 times replacing it my blower motor ended up going bad. Once I replaced the blower motor, the pipe started leaking again. We replaced the pipe again this weekend with guidance from a plumber, he advised the plastic and metal was the problem so he instructed us on how we could create a good connection using cpvc and adapters which we implemented. Last night I noticed the AC is leaking again, this time it is from the same water line but it is on the other side of the coil this time. I feel there is something in the line somewhere causing unsual pressure which is causing the system to leak out at its weakest point. I have lived in the house for 5 years and have not had this issue previously.

I do not know the name of this line so I am having a hard time googling for solutions. No one seems to know how to work on my system and I cannot afford the $10k they want to replace it. I am reaching out here in hopes someone has a good idea of what could be causing the leaks or how to diagnose. Here are some pictures and verbiage to go along with them. Any help is so much appreciated!

Questions

1. What would I call the line marked D when googling. Water intake line?
2. I feel the problem is due to new pressure in the system since the leak keeps moving, how do I diagnose if it is the pressure and what is causing the pressure?
3. Also looking for any other advise or tips to figuring this thing out.

Inside Mapping

A. Condensation Tube

B. Coil the leaking water runs through (first leak was directly before it, second leak is directly after it)

C. Very hot copper pipe (thought was maybe this was shrinking the pvc when it got hot because we kept finding the threaded adapter very loose even after we tightened it, so our last setup removed this possibility)

D. Cold water line that we keep replacing

E. Location the first leak happened before putting brass extension on the 3rd time, after installed it still leaked where brass and PVC met

F. Drain tube from coil which is now leaking

First/Second Leak

Third Leak

Current Leak

Answer 1

Questions

Q: What would I call the line marked D when googling. Water intake line?

A: "Intake" kind of works (we all understand it), but other helpful internet-search terms may include supply, PCV, and radiator.

Q: I feel the problem is due to new pressure in the system since the leak keeps moving, how do I diagnose if it is the pressure and what is causing the pressure?

A: A water pressure guage is how you determine water pressure and I think it will probably be useful (to know, at least generally, the pressure you have). I think that you will want to install a pressure reducing valve and possibly a water hammer arrester as well.

Also looking for any other advise or tips to figuring this thing out.

The problem might be vibrations. If vibrations are present, use a braided connector (for pressure above 25 psi) or you could use a rubber (radiator) hose connection (generally for pressure under 25 psi). Also, secure the pipes with straps wherever possible.

High water pressure can also cause leaks. If this is primarily a pressure problem, then a pressure reducing valve, and/or possibly a water hammer arrestor should help. You may want to install more than one pressure gauge (before and after) the radiator.