On Tue, 23 Feb 2010 16:24:56 -0500, mm
wrote:


I see a copper pointer on the bottom with etch marks on the plate below but
that pointer is already all the way to the left and moving it to the right
just seems to make the offset error worse.

In that case you could risk bending the spring or some other part that

Bad advice by me. I was actually closer with my last line. See
below.

is holding the mercury capsule, but two major concerns. 1) Being a
Mercury Capsule, it might head for earth orbit. 2) A good chance
you'll bend it in the wrong direction (it's confusing) or bend it in
the right direction but so much that the offset pointer won't be able
to correct it. And you only get to bend it once or twice and soon it
will break off. Plus you probably need TWO needlenosses to bend it.

What's the procedure to adjust a Honewell round thermostat to reach the set
point before turning off?

You can try to tip the house while holding the thermostat in place.

This advice was somewhat sarcastic, but it modified just a little, it
was the best advice in my post. If the adjustment with the copper
pointer is insufficient, you can rotate the entire thermostat. The
amount you want to rotate it is the amount it takes to make the number
for example 75 to show up in the same place that currently the number
85 is in. Plus a little more if you want to recenter the copper
pointer. (You now know better than I do how many degrees it is from
end of the scale to the middle with the copper pointer) That would
matter if you want to finish this job with the copper pointer, instead
of remounting the thermostat a bunch of times. You could use
two-sided tape so remounting would go quickly, or you could use
screwws and finish off with the copper pointer.