Diagnosing Natural Gas Furnace Problems

Thermostat

• Homeowners should always begin by checking their thermostats. While there could potentially be something wrong with the furnace itself, thermostats can easily malfunction or be reprogrammed and lead to problems that are easily cleared up by checking settings and ensuring that the thermostat itself is not malfunctioning.

Electrical Work

• Homeowners should carefully check any electrical work connected to the furnace. This means looking at the wiring for the thermostat and the furnace sensors, and checking the breaker, fuses and switches that are connected to the furnace. If homeowners have a multimeter they can gauge the electrical resistance in the wiring to see if there are any problems. A professional can help make these measurements otherwise.

Pilot Light Issues

• If the furnace is simply not heating at all, or if it turns off quickly after it turns on, the problem may be in the pilot light. Homeowners should check standing pilot lights to make sure they are lit and in the proper position to heat the thermocouple sensor. For electrical starters, the electrodes must be positioned at the correct distance and have power flow to work properly.

Overall Cleanliness

• If there is no obvious issue with the pilot light or electrical work, homeowners should give the furnace a full maintenance sweep, cleaning out any dust and debris. A dirty fan can prevent air from flowing correctly, and dirty parts of the main burners may prevent them from lighting up as they should. Dirt and soot can also explain malfunctioning sensors and even more serious damage like cracks in the firebox.