The furnace ignition gets the burners going so they can heat the air and warm your house. An ignition malfunction, therefore, will leave your house cold. As with many problems in life, you should start with the easy solutions before going to the rough ones if your furnace is experiencing ignition problems. Below are some of the simple issues that can trigger furnace ignition problems.
The furnace only ignites if it receives the right signals from the thermostat. This means your furnace will only ignite if:
- The thermostat is working
- You have set the thermostat to heating
- The indoor temperature is lower than the temperature set on the thermostat
Consider a case where you have a programmable thermostat with the wrong date and time. Such a thermostat might not send the right signals to the furnace, and the furnace won't ignite. Therefore, check the thermostat if your furnace is not igniting.
Fuel Supply Interruption
The furnace also won't ignite if it is not getting any fuel or the right amount of fuel. This might be the case if someone did not adjust the fuel supply valve properly or if the valve has malfunctioned. Another reason is if your house is expecting a fuel supply interruption. The latter problem will affect every gas appliance in the house.
Electrical Supply Interruption
Most furnaces, even those that run on fossil fuels, still need electricity. A gas furnace may need electricity for the electronic ignition, for the fan motor, and for the thermostat. For example, your furnace might be off because:
- The thermostat lacks electrical supply so it can't send the right signals to the furnace
- The electronic igniter doesn't have the electrical power to spark it and ignite the burners
Such problems might arise if:
- Something has tripped the circuit breaker
- You forgot to switch on the furnace
- Your house has an electrical blackout
Fortunately, such problems don't mean your furnace has a serious malfunction.
Dirty Air Filter
Many people know that a dirty air filter restricts airflow and interferes with heating efficiency. What you might not know is that a dirty air filter can also trigger ignition problems.
The furnace burners won't get adequate air if the air filter is extremely dirty. Inadequate air means the heat exchanger will overheat (the furnace needs the air to pick up the heat and distribute it inside the house).
An overheated heat exchanger is dangerous, and the furnace has a temperature limit switch to limit the dangers. The fan limit switch will turn off the furnace ignition if it detects dangerously high temperatures.
Contact your HVAC services provider for more information.