Furnace Repair and No-Heat Service in Des Plaines

Furnace problems we are called out for

No heat at all is the call we hear most. The thermostat is asking for heat, the furnace either does nothing or starts and locks out, and the house begins losing temperature. Before a part is replaced we confirm power, the door switch, the filter, the gas supply and any safety lockout the control board has recorded, because a furnace that shuts itself down is usually protecting itself from a second problem.

Failure to start or ignite normally traces back to the ignition sequence: a cracked hot-surface igniter, a flame sensor coated in oxidation, a pressure switch that never closes because the inducer or the vent is restricted, or a control board that is not sending the signal. Each of those looks identical from the hallway and completely different at the unit.

A furnace blowing cold air often means the burners lit and then dropped out on a flame-sense fault, or the blower is running on a fan setting while the heat call has ended. Short cycling — heat for a few minutes, then off, then on again — commonly comes from a restricted filter, a dirty flame sensor, an overheating limit switch, or a furnace that was oversized for the house when it was installed.

Weak airflow, unusual noises and thermostat trouble round out the list. Rumbling on ignition, a metallic screech from the blower, booming at start-up or rattling panels each point at something specific: burner condition, motor bearings, delayed ignition or loose sheet metal. New noises are worth a call before they become the reason for a replacement.

A furnace that buzzes, clicks or hums without starting may have a problem in the ignition sequence, inducer motor, transformer, capacitor, blower motor or controls. If the burners light and immediately shut down, the flame-proving or safety sequence needs to be tested. Do not repeatedly reset the furnace or bypass a safety switch.

How the diagnosis works

The technician reads the control board's fault history, then checks the sequence of operation in order — call for heat, inducer, pressure switch, ignition, flame proving, blower, limit. That sequence tells us where the system stops instead of leaving us guessing, and it means you are told what failed rather than what was swapped.

Combustion and safety checks are part of every heating repair visit. We look at the heat exchanger, the venting, the gas pressure and the condition of the burners. If we find a cracked heat exchanger or an unsafe venting arrangement, we show you what we found and explain the options rather than simply condemning the unit.

Igniters, flame sensors, pressure switches, capacitors, limit switches, blower motors, thermostats and control components are the parts that fail most often, and the common ones ride on the truck. That is why a large share of no-heat calls are finished on the first visit.

High-efficiency furnaces produce condensate during heating. A clogged trap, blocked drain, failed condensate pump or improperly draining line can interfere with the pressure-switch and ignition sequence, causing a no-heat condition or water around the furnace. The drainage and venting system should be tested before replacing a pressure switch or control.

Repair or replace?

We will not talk you into equipment you do not need. As a rule of thumb, a furnace under roughly twelve years old with a single failed component is worth repairing. Once a unit is past fifteen years, has a cracked heat exchanger, or needs a repair that is a significant fraction of the cost of a new system, replacement usually becomes the better spend.

When it is close, we give you both numbers and let you decide. If you choose to move ahead, the details are on our furnace replacement and installation page.

Seasonal heating maintenance before the cold sets in

Most of the no-heat calls we take in December start as something small in October: a flame sensor already coated enough to drop out on a long run, a filter that has been in place since spring, a condensate trap beginning to close, or an inducer that is noisier than it was last winter. A fall heating visit is the point where those are cheap to deal with.

A seasonal visit covers the burners and flame pattern, heat exchanger condition, igniter and flame sensor, safety and limit controls, gas pressure and combustion, venting and the fresh-air intake, condensate drainage on high-efficiency equipment, filter and blower airflow, accessible electrical connections, and thermostat and control operation. Checking the complete sequence before heating season can catch the restrictions and control faults that lead to short cycling or no heat, without duplicating the deeper diagnosis covered elsewhere on this page. You get a plain summary of what was found and what, if anything, is worth doing before the coldest weeks.