Identification

• One reason the circulator might not work is electrical. The fan can only move if electrical energy is flowing through the furnace. Check your breaker to see if the breaker panel is on for your furnace.
  
  

Considerations

• Another consideration to check out is if your furnace has a condensate pump. When a condensate pump is full of water, the furnace turns off the fan. Empty out the pump when it looks full and the furnace should be able to start up fine.
  
  

Speculation

• The fan might also stop working because the pilot light is not on. The pilot light is the indicator that there is a fire working in your furnace. Like the condensate pump, when something is wrong with the pilot light, the furnace will not work. There are a number of reasons why the pilot light might not be on. The gas valve might be partially shut or the control board could be broken. Investigating the pilot light is an important consideration for a nonworking fan.