Common Furnace Issues
Furnaces that have an efficiency rating of 90% and higher have a PVC exhaust pipe and sometimes an air intake pipe. This PVC pipe is white in color and usually runs horizontally outside of the home. Sometimes, snow, ice, leaves, or other debris can obstruct one or both of the pipes causing the furnace to shut off. If the furnace is located in the basement of the home, the exhaust pipe is usually only a couple of feet above ground level and can be easily reached by the home owner.
Check outside to make sure there are no visabile obstructions at the opening of the pipe. Remove any debris. You will then need to turn the furnace switch off. Wait for 10 seconds and then turn it back on. Note: The furnace switch usually looks like a regular light switch and is located on or near the side of the furnace. If your furnace doesn't have a shutoff switch, you can also reset it by shutting off the furnace breaker for 10 seconds.
A dirty air filter can restrict airflow, causing the heat exchanger and blower motor to overheat. This can shorten the life of your equipment and possibly leave you without heat. If you have a 1" filter, a good rule of thumb is to change it on the first day of each month.