When the temperature goes below the set temperature of the thermostat the furnace doesn't start up again?

Answer 1

Step by step:

1) Try turning the thermostat off then on again.
2) Check your breaker/fuse box and make sure the breaker is on or the fuse not blown.
3) If your furnace has another power switch make sure that hasn't been tripped.
4) Have you run out of oil?

After you check all of these, then push the restart button on your furnace no more than twice. The furnace should start to run through a heating cycle and then the burner will catch. If the furnace starts a cycle but does not catch then you can have a few problems. The most likely of which is air in the line and you will need to bleed your furnace.

If the furnace doesn't run through any cycle then the most likely culprit is your thermostat itself. They are fairly easy to replace, but if you aren't comfortable with that type of repair, call someone. It isn't an expensive job.

If you haven't had your furnace inspected this year, then get someone in to do it. They will have to run through all of the above things when they clean/inspect it including checking the thermostat.

Answer 2

First, try re-setting your thermostat. Switch it off then back on to heat. Set the desired temperature, and see if the heat starts up. If not, then it's definitely not working. You should get your furnace looked at right away- depending on where exactly you live, you might not be able to survive after a whole day of no heat!

Good luck!!

Answer 3

Have you tried to use just your fan? set the fan setting to "ON" not "AUTO" and see if it works that way. Or you can try the AC. Most likely you are not giving it enough time to come on.
Most furnaces have a timer inside them that wont allow them to start until after certain point. If the blower is coming on and you are not getting heat then you, more than likely, have a tripped limit switch.
This could be due to a dirty filter or faulty burners depending.
I would suggest taking out your filter and resetting your limits switches. There could be several.
I would suggest calling a service tech out to your house. Most service calls are inexpensive and considering you have a heads up you can talk jargon and B. S. them enough to where they think that you know what you are talking about and fix it cheaply.

Answer 4

Probably due to a bad igniter.