Use this chart to identify a wide variety of conditions that may be preventing your furnace from working at peak performance, and basic solutions to try before calling a furnace company to have your furnace serviced.
NOTE: The servicing of furnaces by un-qualified personnel can lead to costly problems, health risks and fire hazards. Our technicians have the training, test equipment and facilities to properly service your furnace.
Problem
Possible cause Solution
Furnace won't run
1. No power 1. Check for blown fuses or tripped
circuit breakers at main entrance
panel, at separate entrance panel,
and on or in furnace; restore circuit
2. Switch off 2. Turn on separate power switch
on or near furnace
3. Motor overload 3. Wait 30 minutes; press reset
button. Repeat if necessary
4. Pilot light out 4. Relight pilot ONLY if you know how to do so and are comfortable with doing so.
Otherwise, call a professional.
5. No gas 5. Make sure gas valve to furnace is
fully open
Source:****://www.****/repairs/furnace-troubleshooting.html
hope this can help