I believe the member here "mtrentw" has made a goosing tool using a garden sprayer and a needle for pumping up a basket ball.
Still not clear to me what "goosing" does and why it would be needed? Is it simply topping up a system that either due to leak or trapped air, needs more water/refrigerant mix?
Yes, small leaks will cause the pressurized system to lose it's pressure, needing water/antifreeze mix to be added. When the tech said the loops are dry, they meant the brine (water/antifreeze) level had dropped enough to cause circulation pumps to stop working. In the case of a small leak, slow leak, changing to a non-pressurized pump system, which has a canister/vessel that maintains a certain water level. By keeping an eye on the level you can add brine when the level drops.
Attached are a couple images of my pressure maintenance system. I NEEDED this about 4 years ago when I had a sow steady leak. I used this system to pump in a bottle of leak stop fluid and circulated for a day at higher pressure. I've not since had notable leak problems. I may need to add a cup to a pint every year, if that. I may one day switch to non-pressurized system, but don't see a need at present.
One more hands off option is this $500 pressure maintainer for small hydronic systems. Can hold up to 6 gallons of antifreeze solution and automatically maintains a set pressure.
Ok I see you've added some of your own plumbing with a faucet. Do you have a closeup or parts list for the male end of your goosing tool as it enters that faucet. Didn't I see someone plugging that ( with a basketball needle valve on the end) into a PT port?
My system had drain valves/hose bibs. As such, I just removed the hose sprayer wand and used a barbed fitting and a couple adapters to 3/4" female Garden Hose Thread to connect. If you don't have a service valve/faucet to tie into, but have pete's ports, you would need to firugre out how to adapt to a basketball type needle or such. One caution when goosing the system is to make sure there is no air in your fill line. I always open the valve to backflow into my sprayer to ensure the air purges into the tank before I start pumping it up.