de-soldering - unsuccessfully

[Jupiter01]

I was recently trying to repair a leak on 15mm copper pipe. I was sweating off 2 elbows. One came off pretty quickly. I saw the solder run, twisetd the fitting and it came away. Another elbow did not shift at all. I heat it continuously and with breaks. No joy. I also tried pasting some flux on it but that didn't shift it either.
In the end, I cut the pipe before the fitting, which caused me additional agro...

Any ideas on what might have been causing this and how I get around it in the future?

 

[denso13]

Any water in the pipe?

 

[Jupiter01]

Any water in the pipe?

ah, it's possible that this section had some water sitting it it. Hadn't thought about that.
How empty/dry does it need to be and how do I solve that? I did run te taps but I h=guess this pipe sits at a lower level than the taps.

Also, I didn't notice any steam from the pipe when I was heating it...

 

[denso13]

Pretty dry, if only damp then the flame will clear it. But more than a few drops will kill the heat.