On Mon, 22 Feb 2010 18:23:12 -0600, (Lp1331 1p1331)
wrote:

The adjustment you are talkig about s called a heat anticipator. RBM is
correct in that is adjusted to the amperage draw of whatever the
thermostat is controlling. The others are also correct in that digitals
are much more accurate, and now a lot of them actually cost less than
mercury bulb mechanical types. Larry

Digital thermostats can be very complicated to operate. Check on that
before buying.