HVAC emergency in Chicago? Call Bernie's Heating & A/C Service now! Same-day service available for all heating and cooling emergencies.
If your furnace runs for a few seconds and shuts down, do not let anyone jump straight to replacement. Most calls like this start with a flame sensor, ignitor, pressure switch, venting, or airflow diagnostic.
A furnace that starts and then shuts off is usually protecting itself. Modern gas furnaces prove draft, open the gas valve, ignite the burners, verify flame, then keep running only if every safety check passes.
When one of those checks fails, the board shuts the furnace down. That is why the symptom can look simple from upstairs but point to several different parts in the basement.
The classic pattern is: thermostat calls for heat, inducer starts, ignitor glows, burners light, then the flame drops out after a few seconds. That often points to flame sensing, but we still test the full sequence before quoting the repair.
Typical repair: $89-$150
Burners light, but the control board cannot reliably confirm flame. This is one of the most common repairable causes.
Typical repair: $150-$250
A hot-surface ignitor can glow weakly or crack, causing inconsistent ignition or repeated lockouts.
Typical repair: $180-$350
The furnace must prove safe draft before it keeps firing. Blocked intake, exhaust, condensate, or switch tubing can stop the cycle.
Typical repair: $120-$600
A clogged filter, dirty blower wheel, weak motor, or restricted ductwork can overheat the furnace and shut the burners down.
These checks are safe for most homeowners. Stop and call if you smell gas, see flame rollout, hear repeated ignition bangs, or have carbon monoxide alarms going off.
Replace a dirty filter and confirm the blower door is fully latched.
Set the thermostat to heat and fan to auto, then raise the setpoint a few degrees.
Open supply registers and make sure return grilles are not blocked by furniture or storage.
Check that the furnace switch and breaker are on if the furnace is completely dead.
Do not bypass pressure switches, rollout switches, flame sensors, or limit switches. They are safety devices, not optional parts.
Do not keep resetting a furnace that locks out. Repeated lockouts need diagnosis, especially on gas equipment.
Do not ignore a cracked heat exchanger warning, flame rollout, soot, or carbon monoxide alarm. Shut the system off and call for service.
Older Chicago homes often have basement furnaces in tight mechanical rooms, older duct runs, dusty returns, and limited return-air paths. A furnace may be mechanically fine but still overheat or lock out because airflow is restricted.
That local context matters. A Portage Park bungalow with a packed basement and one undersized return needs a different diagnosis than a newer condo furnace closet.
See broader no-heat repairs, pricing, and repair-vs-replace guidance.
For ignitor, pilot, gas valve, and ignition-sequence problems.
Bernie's is based at 3704 N Cicero Ave near Portage Park.
The most common cause is a dirty flame sensor. The burners light, the sensor does not prove flame reliably, and the control board shuts the gas valve for safety. Failed ignitors, pressure switch problems, venting issues, clogged filters, and limit switch trips can cause similar symptoms.
No. One reset after checking the filter and thermostat is reasonable, but repeated lockouts mean the furnace is stopping for a reason. Repeated resets can mask an ignition, venting, overheating, or carbon monoxide safety problem.
Common repairs usually run $89-$350 depending on the cause. Flame sensor cleaning is often $89-$150, ignitor replacement is commonly $150-$250, pressure switch or venting diagnosis often runs $180-$350, and blower or airflow repairs can cost more.
Usually not. Many start-and-stop calls are repairable ignition, sensor, or airflow problems. Replacement only enters the conversation when the furnace is very old, unsafe, has a cracked heat exchanger, or needs a major repair that no longer makes sense for the age of the equipment.
We test the ignition sequence, safety switches, flame signal, and airflow before recommending parts or replacement. Call Bernie's for repair-first furnace service in Chicago.