Keeping the TXV wet with rags(cut small and wrapped) nitrogen flowing thru the TXV, unsoldered the old put the new one in. All of the sudden one spot on the back of the TXV didn't take, here is my question. Do you tech say you have to use 45 % or higher silver solder. Manufacturers say 8 % minimum. It was a fiasco trying to solder finally getting it but it looks not not good. Any situations where you just couldn't get it to flow using 20% rod? How were you sucessfull? It appeared not enough heat but A11 Turbo head on 3 ton TXV I would think adequate....what a fisaco after 31 years in this and to be humbled is humbling...