Originally Posted by 3Ms75Argosy
I do find that opening both the drain and the relief valve hastens the draining process.
For what it's worth...
Rather than do that, I open a water faucet inside the trailer. That also hastens the draining of the tank, and it also draws the water in the line into the tank also. Much less to blow out then.
One of the things I have learned the hard way is that sometimes opening that relief valve sometimes causes a small amount of debris to settle in the valve, not allowing it to seal as well, forcing you to have to replace the valve or attempt to flush the valve clean.