I simply bought some muriatic pool acid from HD at 30%
Diluted to 10 to 15%
Disconnected lines at pump
Used 2 funnels secured ends into hoses and secured to something so they dont fall and poured in the acid.
Let it sit for 5 minutes.
drained it out
Then flushed with a hose. should keep a hose at the ready if your using acid.
It looked clean on the inside of the water condenser pipe connection and I got a small amount of brown green scum came up in the funnel. You know it has filled the pipe when poured into one side it comes out the other with the hose ends above the tubing coil.
It only takes maybe a qt of acid water mix to fill the pipe.
I am clumsy and spilled the acid-water mix on my shorts which the hose easily flushed off with no effects.
Websites will say recirculate a 5% solution for a while till clean. I do have a rubber impeller pump and I suppose could use bucket. I kept imagining though the pump leaking acid or it spraying acid on me with the pump. How do they know when it is clean?