On Feb 22, 6:23*pm, (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

The heat anticipator is not whats off with that issue, the anticipator
is correctly set to what it controls and controls how wide a swing you
get before the thermostat comes on and goes off, the issue is its 10f
off which happens with those dial units if someone messed with it not
knowing how to calibrate it to the thermometers "temp" or forced it
over to one side. Honywell used to supply with every round thermostat
a little wrench that slips over the nut so you can turn the dial to
get it set to run as the thermometer temp states, its a real real thin
wrench but maybe Ace or a heating supply house has one. Often they
wernt packed in the box so you had to ask and maybe pay 35c for one.
One of mine is off now and I cant find my wrench, its off 6f, but it
works fine with a 2f swing, so get used to it or get a wrench. Now if
temp swings to much from on to off, then look at the anticipator.
Those units are foolproof in design, and would outlast digital, they
are not made anymore because of the Mercury bulb and disposal
concerns. They still make the round style, but took out the mercury.