I recently bled my radiators for the first time in about 2 years, and after that, I started getting 6 cups a day of water dripping out of my pressure relief pipe.

Is the valve shot and the air in the system was just allowing room for expansion?

Going away for a few days and don't want a flood...

 

Bleeding of the radiators should have nothing to do with the relief valve leaking. How much pressure is on the system (hot)? Do you have a bladder type expansion tank or one with a drain valve?

 

Sounds like a water-logged expansion tank. The air you bled out probably was allowing expansion to occur. When you bled it the pressure went up and the relief started to leak. That is if you didn't over-pressurize the system or something to bleed it.
What's the pressure cold? Does it go up when the boiler runs? If so look at draining or replacing the expansion tank. If the pressure is the same hot or cold you may have just over-filled the system. Drain it down to zero and let the auto feed fill it back up. Should stop at 12 lb. If not you may have a feeder problem.

 

I have a bladder-type expansion tank. It's less than a year old and was professionally installed. Hope that's not the problem.

I am not sure what the pressure is on the system. I'll check.

Thanks again,
Brian