Heating System Problems

Heating System Will Not Run — no heat, no fan (indoor blower)

• First, go to the thermostat and turn the Fan switch to ON and see if the blower comes on or not. The Fan switch is normally left on Auto, but when you manually switch it ON, that commands the blower to run. With some units, there may be a short delay (30 seconds) before the blower starts. If the blower does not come on, then continue with this section. If the Fan (indoor blower) runs when the Fan switch is ON, then at least you are getting power to the furnace and at least one function works (Fan)—go to the "Fan Runs" section below.
  
  
• If the Fan does not run with the Fan switch set to ON, that suggests a power or control problem. If your furnace is in the attic or garage, make sure that the "light" switch on the side of the unit has not been turned off by accident. Also check the circuit breakers in the garage (or wherever your main electrical panel is located). Gas heating systems use electricity for blowers and control systems, but it's highly unusual for a gas furnace to trip a breaker—this is something to get checked by a professional. Heat Pumps have a second set of breakers or fuses in a box near the outside unit. Likewise, it's unusual for a heat pump to trip a breaker or blow a fuse. If that happens more than once in a long while, get your system checked out. Of course, the Fan not running could mean the blower motor has failed.
  
  
• Read the Owner's Manual that came with your furnace. It will have specific troubleshooting and safety information.
  
  
• If the indoor blower (fan) doesn't run, the furnace won't work either. At this point, a service call is required.
  

Fan Runs (switched to ON) but Heating System Does Not Produce Heat

• Check to see if your hot water heater is working. If it works, then at least you know you are getting gas (to the house). But check to make sure the water heater pilot is actually lit. You can have hot water for several hours even if the gas is off.
  
  
• Check the thermostat. It should be set on "Heat" and the desired temperature should be set higher than the house temperature. Fan should be set to "Auto." The "On" position just controls the fan. Programmable thermostats may be set incorrectly, so override the program to make sure the thermostat is not at fault.
  
  
• If your furnace has a pilot light, check to see if it's lit. Lighting instructions are on the furnace. Use a long Bar-B-Que lighter, not a piece of paper. If you don't want to tackle this yourself, give us a call. A pilot light that goes out frequently may indicate a problem with the furnace. Do not try to manually light a furnace that does not have a standing pilot light (most newer furnaces don't have them). Read the instructions on the furnace door or the owner's manual before doing anything.
  
  
• If the indoor blower runs but the furnace does not produce heat or just blows cold air, and you've tried the above, a service call is necessary.

Heating System Runs but Shuts Off Before House is Warm

• If the heating system starts up, but shuts off (or blows cold air) after a few minutes (before the house gets warm), this may indicate that the furnace is overheating and an internal safety switch is shutting it down. You may have really dirty filters blocking the air flow through the heating system. Or it could indicate a serious problem with the burners or furnace vent. This is a hazard which should be checked out immediately by a service technician. Overheating can crack the heat exchanger (which is an expensive repair) and a cracked heat exchanger has to be replaced because it can leak Carbon Monoxide into the house.
  
  If your filter is the "permanent" washable kind, replace it with a disposable filter. Permanent filters can block too much air even when clean. Check and make sure all registers are open and that no filters are installed in the registers. If changing the filter and opening all the registers doesn't fix the problem, you'll need a service call.
  
  
  

If you smell gas, call the gas company from a neighbor's phone. Don't use the phone (or a cell phone) in your house until the leak has been fixed.

Atmos Energy's Emergency number is 1-800-556-5469

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