Has anyone here ever replaced a thermostat?

[Paper Roses]

15. Hope I am not in trouble. This AM, the first floor was 55 when I got up.

The Thermostat was set at 64. Got brave enough to pull the cap off the unit(round Honeywell). The inside is not like the old mercury one we had. It is circuits.
I blew some compressed air in the back of the face unit and on the wall mounted part.
I had flipped the emergency switch off.. I touched the prongs gently with a q-tip and reattached the face part.
Jacked up the heat to 70 and it is now running. I am trying to get the heat up to a civil level.

I don't know if this little chore did anything and if I need the fuel company to come. Big $$ and right in the middle of a blizzard.

I just went to check and it is still going. Something I never noticed, there is a little light bulb(?) shaped icon showing on the left side of the dial. Don't know what it is and I have no paperwork to check. It was installed with the new furnace 7 years ago and nothing was left for me to refer to. I turned the dial just a little, bulb disappeared and then came back. Since I never had occasion to fiddle with the thermostat before, maybe this was always there and just shows that the furnace is on.

Talked to fuel company this AM and told him what I did, he suggested that I just watch it now that it is running...maybe it was just dust.

They will come for a service call even if we get a ton of snow. I'm keeping my fingers crossed.