Having a furnace that produces cool air when you need heated air is a nuisance, especially during winter. If you switch the fan on and you hear it blow, but there is no ignition or the burners are not heating up, it might be a matter of a simple setting on the thermostat or even just a dirty filter. However, it could be something more complex that requires an urgent heating repair.
Understanding how the furnace works will provide valuable information for determining the problem and finding the appropriate furnace repair technician.
What Does It Mean When the Blower Runs but the Furnace Won’t Ignite?
If the blower is on and the burners still are not lighting, then the furnace might be malfunctioning somewhere in the following process.
Potential problem areas are:
- Thermostat or control signal
- Electrical power
- Ignition system
- Flame sensor
- Gas supply
- Pressure switch
- Safety restrictions or limitations
- Furnace control board
The particular order of the various furnace models varies; thus, the noises and behavior of your particular furnace might provide great hints.
What Are the Most Common Reasons a Furnace Blower Runs Without Ignition?
There are a few problems that can stop a furnace from accomplishing an ignition sequence properly.
Briefly, these are some of the other possible causes:
- A malfunctioning thermostat
- Obstruction of the fuel inlet or outlet during firing or drifting
- A failed pressure switch
- There is a problem with the control board
- Insufficient gas supply
- A faulty gas valve
- Tripped electrical breakers or service switches
Substituting components by appearance can be a costly process since many different fault conditions manifest themselves with the same symptoms.
How Can You Safely Diagnose a Furnace That Won’t Ignite?
You should confirm that the appliance has been switched to heating and the temperature has been set above the room temperature. If the thermostat is powered by batteries, ensure they have not gone bad.
You can also check:
- Does the furnace get electricity?
- If the circuit breaker was tripped or not
- Whether the furnace service switch is turned on
- Whether supply & return vents can be seen
- If the outside air inlet/exhaust pipes look clogged
- If the furnace is showing an error code (no error if it does not)
Do not cut or try to manipulate access panels or bypass safety switches.
What Does the Furnace Sound or Behavior Tell You About the Problem?
When furnace ignition problems arise, you can use careful listening to what occurs immediately prior to the blower running to help identify the problem.
Record observations, remembering to include:
- Determine if the furnace tries to start
- In fact, you can hear clicking, whether you like it or not
- If the burners do not light, they will need to be relit
- Immediate starting of the blower
- If the error code or flashing lights appear
- The amount of time spent operating the furnace prior to its shutdown
This data can be very helpful for a tech to run a furnace diagnostic.
When Is a Furnace That Won’t Ignite a Safety Emergency?
Some things are to be taken seriously when your furnace refuses to start, but it’s not an emergency in and of itself.
When you see any of the following, leave the area and call the proper emergency furnace repair services:
- Loud stream of natural gas odor, or strong odor of natural gas
- Burning electrical odors
- Visible electrical damage and/or visible sparks
In case of gas odor, one should refrain from igniting the furnace and using the electrical switches near the source of the leak. You must listen to the instructions given by the gas company in emergencies.
When Should You Call an HVAC Professional?
Without the repair being undertaken immediately, costs of up to $1,200 may occur, making it crucial that you call an expert as soon as possible. Certification of professionals will also require testing of the gas supply, electrical controls, flame sensing, pressure switches, and ignition.
It becomes extremely important to seek professional help when:
- The furnace attempts to ignite but fails to do so
- The burner flames start and stop on their own
- An inbuilt part seems to be damaged
- You suspect that you have a problem with the gas supply
- The furnace continues to show persistent fault codes
- The problem resets for a short time and is then repeated
- This system is an aged system with several issues, and it may be failing to function properly
A maintenance company like Sunny Appliance Repair can be able to determine if there’s a simple repair to be done for the furnace, or if the furnace has a bigger issue.
Conclusion
The functioning of the furnace can be interfered with by the dirtiness of the filter, a malfunctioning thermostat, a clogged vent, igniter failure, a malfunctioning flame sensor, and failure of the pressure switch or the gas supply.
In case it fails to start, do not attempt to take the furnace apart or bypass the safety controls of the furnace. Get in touch with a qualified HVAC technician to examine and fix the heater.
