Coming from within the wall, there's a relatively loud (and sometimes
quite annoying) constant clicking sound at even, though gradually
changing intervals. If I turn the heat up, the clicking starts
immediately with a fraction of a second between each click. Usually
that lasts for a few seconds and gradually slows down to a few seconds
between each click. Of course, it keeps doing this in cycles and
doesn't let up much between cycles. I'm not sure what type of heating
system it is, but there are baseboards, and when I turn the heat up, it
sounds like water or something starts circulating. Any idea what's
causing this and if it's normal?