Hasn't been drained in over ten years? Don't you have the system checked out at least every other year by a service tech? If so, how come they are not draining the tank? Shut off the valve installed leading to the tank from the boiler. Open the drain valve and see what happens. Should be a metal tag on that valve saying must be left open during operation of the boiler so turn off/down the tstat when playing with the boiler. As for the drip, it is normal when one tests a pressure relief valve. There is a seal to keep water in until the rated pressure is reached and debris can catch on the seal and drips happen. Use a coffee can to catch the water. No big deal.

Leaks can occur in these areas of the humidifier: https://www.airconditionersductless.com/ Improper drainage. If the drainpipe for the humidifier has a blockage or a kink, it won’t drain as quickly as it should. If you notice that the line has twisted, straighten it and check to see if it drains faster. There could be an air lock in the line that you can clear by forcing water under pressure into the line. Clogged evaporator pad. Over time, hard water forms a scale on the pads that prevents the pad from absorbing all the water. If you notice hard water scale coating the pad, it’s time to replace it. You’ll also get more beneficial humidity with a new pad, since the scale also slows the passage of air through the pad and the consequent evaporation that creates the water vapor. Problems with solenoid or float. Sometimes the culprit for your humidifier’s leaking water is an improperly adjusted float. Your system may use a solenoid to control the water going into the humidifier. Unplug the solenoid and shut the water off at the saddle valve. After removing it, blow through it to dislodge any dirt particles that may be trapped inside. Replace the solenoid after you’ve determined that the line is clear.

Last year I began getting a sporadic release from the T&P valve on my gas water heater. Like most DIYers I pursued the easiest solution and replaced the T&P valve with an exact replacement (there are different T&P valves and different specs).. The problem continued. I called Watts (the manufacturer of the OEM and replacement T&P valve) and spoke to an engineer there. I asked what the incidence of defective T&P valves is. His reply was that since T&P valves are a safety device there is immense product liability and they are throughly tested and the DOA rate is EXTREMELY low ... almost none he said. That's when I discovered "thermal expansion". Sure enough, I did have a PRV out at the water meter that prevented the water in the house plumbing system from equalizing presuure by backflowing into the water system. With a closed plumbing system every time my water heater fired the water would expand and if that excess pressure was not relieved by coinincidentally opening a faucet or flushing a toilet at the right moment the T&P valve would "burp" a cup full of water. I found a nifty pressure gauge with a "tattletale" needle at ... http://www.wattspremier.com/watts/showdetl.cfm?&DID=15&Product_ID=93&CATID=1 Low and behold the tattletale needle showed enough pressure to pop the T&P valve. So, instead of treating the symptom I cured the disease ... installed a thermal expansion tank and all is well. Funny thing is, now that I don't have a thermal expansion problem I also don't have those dripping faucets anymore. Maybe because the faucets don't have to deal with water pressure spikes up to 125lbs???

I'ts leaking from under the top lid. The manual bleed valve is located on the side on mine. Opposite side from the pressure gauge. The protective filter material that covers the "ping pong ball" inside is history. I tried to remove the cage that houses the ball but it won't budge. Pulled one of the two clips that appear to hold it in. It promptly snapped off. Even with that missing, the cage isn't moving. the "O" ring inside that the ball seals on appears to be OK. The leak is just a trickle, but it's kind of irritating. Thanks