I got a pair of Perlick 525s for my DIY kegerator. I have only tried one so far, but it is a bit hard to close--I have to tell people to push it back a bit further than their instincts first tell them. If they don't, it will continually drip slowly. And even when I consciously close it the way I think it should be closed, it sometimes drips continuously (maybe 10-20% of the pours).
When the tap is closed, it moves back evenly and then there is some resistance (the point most people stop). It isn't a hard click or anything, just a bit of resistance that is enough that most people will stop moving the tap. If you stop here, it drips. It will go back a tad further though if you apply a bit more pressure. Both of the taps do this (even though one has no beer so I don't know if it drips). Is this normal?
I've tried playing with the external nuts on the faucet. There are two where the tap handle is attached. I think the bottom one should be tightened pretty well as it is attached to the inner valve. The other one (closer to the handle) just appears to adjust how high the handle goes and it can be positioned/tightened all the way down or several millimeters above the lower nut. Where and how tight should the upper nut be positioned? Should it also be tightened down as far as it will go?
I haven't taken it apart yet, but the keg just kicked, so I can try that next. Any pointers on what I should look for or how I should adjust it when putting it back together?