If your furnace is acting up, you can do a few things before calling a technician for help. Here are some of the measures to try.

1. Confirm the Thermostat Settings

If the temperature is low, then you should confirm that the thermostat has the correct temperature setting. The furnace only runs if it needs to produce heat, and the furnace only produces heat if the temperature in the room is lower than the temperature on the thermostat. Maybe someone accidentally set the thermostat to "Off" or "Cool" instead of "Heat." For a programmable thermostat, the wrong date and time setting can also interfere with the heating function.

2. Check the Power Delivery

Check that your furnace has electricity — even if you have a gas furnace. Furnaces require electricity to run different electronic and electrical parts. The furnace motor or electronic igniter won't work if the system is not getting electrical power. Confirm that the fuse is not blown, something has not tripped the circuit breaker, and that you have plugged the furnace.

3. Check the Fuel Supply

You also need to confirm that the furnace is getting fuel. The confirmation will depend on the type of fuel your furnace uses. Here are a few tips to help you confirm fuel availability and delivery for a gas furnace:

• Your house has gas in case you use piped gas
• The gas tank is not empty in case you use gas
• Someone has not shut the gas supply valve

You know the problem is restricted to the furnace if other gas appliances in the house, such as the cooking range, are functioning as usual. Note that you should not try DIY repair of gas appliances — the risk of an explosion is not worth the money a DIY repair can save you.

4. Reset the Furnace

Your furnace has a safety feature that shuts it off if it senses a looming catastrophe. The furnace might shut itself off if it overheats, detects fuel leakage, or experiences an electrical malfunction. In such a case, you have to reset the furnace to get it working again.

The location of the reset button depends on your furnace's make and model. The reset procedure majorly depends on the fuel type. Here is a general reset procedure for a gas furnace:

• Confirm that the pilot light is off
• Set the lowest temperature possible on the thermostat
• Turn off the main gas supply and electrical supply (but not the pilot light gas supply)
• Light the pilot light
• Turn on electricity and gas
• Press and hold the reset button for 30 seconds
• Increase the thermostat setting to your desired level

Something is wrong with your furnace if it doesn't light up after you follow these steps. In such a case, switch off the furnace and call a technician. You probably have a serious furnace malfunction on your hands if the above measures don't help. Consult a heating repair technician for professional diagnosis and repair.