changing a 3 ton TXV

[leathernecke5]

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...

[ar_hvac_man]

Maybe too much pressure on the n2?

[leathernecke5]

Possible, getting older the hearing is not as good, even put the hose in my ear to ensure I could here my flow small amount just moving the gauge low side

[ar_hvac_man]

I use 15 with no issues. I go hot and fast

[Dchappa21]

I use 15 with no issues. I go hot and fast

Yep.. only need 45 if its a steel or brass valve.