Sorry I posted this in the water heater forum by mistake so I am repeating here.
I have an expansion tank over my boiler. I came in to catch it dripping down the side and noticed the hard water evidence of prior dripping onto the boiler.
Is it supposed to be doing this? How does it need to be adjusted? If this is important then I need to call a plumber. Thanks in advance
While it could be the connection to the tank, it is probably more likely the tank is shot. It should be primarily filled with air. If you rap it with your knuckle, you should be able to tell if it is full of water or not. If it is full, it is almost certainly shot...replace it.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014
The nice thing about expansion tanks is they are easy to replace. If it's full of water, it will be heavy and since they are often awkward, use care when unscrewing it.
Unfortunately, sounds like you need to replace it. But the good note, is that they are relatively inexpensive and require no real plumbing knowledge. Purchase a good one, the kind with a bladder inside. If it is full of water it will be heavy so don't drop it on your foot.