Your Fort Wayne furnace just stopped heating and you want to know if you can fix it yourself or if you need to call an HVAC professional. This guide walks you through 10 troubleshooting steps, from the obvious-but-commonly-missed to the moderately technical. If you get through the list and still have no heat, you need professional service.
Safety first: If you smell gas, evacuate immediately and call the utility company's emergency line. Do not flip switches, light matches, or use electronics.
Step 1: Check the Thermostat
Sounds stupid, works 20% of the time:
- Is it set to "Heat" (not "Off" or "Cool")?
- Is the temperature setting above the current room temperature?
- Is the display working at all? If the display is blank, batteries may be dead — replace them.
- If you have a smart thermostat, check if a schedule or "Eco" mode is overriding your manual setting.
If the thermostat is fine, move to step 2.
Step 2: Check the Circuit Breaker
Your furnace has a dedicated breaker (usually labeled "furnace" or "heat"). Go to your electrical panel and look for:
- A breaker in the tripped position (between ON and OFF)
- A breaker that feels warm
- The furnace breaker completely in the OFF position
If it's tripped, flip it fully to OFF, wait 10 seconds, then flip to ON. If it trips again immediately, stop — that's an electrical problem requiring a professional.
Step 3: Check the Furnace Switch
Every Fort Wayne furnace has a dedicated power switch near the unit (usually on the wall or a red switch on the furnace itself). It looks like a light switch. Sometimes this gets bumped off by someone carrying things through the basement.
Flip it to the ON position.
Step 4: Check the Air Filter
A clogged filter is the single most common cause of Fort Wayne furnace problems. When the filter is blocked, airflow drops, the furnace overheats, and a safety limit switch shuts it down to prevent damage. No heat despite a functioning furnace.
Pull the filter out. If you can barely see light through it, replace it. If it's brand new or clean, skip to step 5.
Pro tip: Fort Wayne homes should change filters every 1-3 months depending on pets, dust, and occupancy. Check our HVAC maintenance guide for the full schedule.
Step 5: Check the Gas Supply (Gas Furnaces Only)
If you have a gas furnace:
- Go to the gas meter and check that the gas is on
- Check any gas appliances (stove, water heater) — if they work, gas is flowing
- Find the gas shutoff valve on the pipe leading to the furnace. The handle should be parallel to the pipe (open). Perpendicular means closed.
- If gas bill unpaid, NIPSCO may have shut you off
Step 6: Check the Condensate Drain (High-Efficiency Furnaces)
High-efficiency (90%+) furnaces produce condensate water that drains through a small pipe. If this drain clogs, the furnace shuts off for safety.
- Look for a small PVC pipe coming from the furnace to a floor drain or condensate pump
- Check the condensate pump reservoir — is it full?
- Is there any water pooling around the furnace?
If the drain is clogged, you can sometimes clear it with a wet/dry vacuum on the drain outlet. If the condensate pump is dead, that requires replacement.
Step 7: Check the Pilot Light (Older Furnaces)
If your furnace is older (pre-2000s), it may have a standing pilot light that goes out. Look for a small flame in a pilot assembly. If it's out:
- Find the reset button or knob on the gas valve
- Follow the relighting instructions printed on the furnace (usually a small plate)
- If the pilot won't stay lit after multiple relights, the thermocouple is likely bad — that's a $150-$350 professional repair
Step 8: Reset the Furnace
Most modern furnaces have a reset sequence: turn the power switch off, wait 30 seconds, turn it back on. Watch the ignition sequence. Many Fort Wayne furnaces have a diagnostic LED that blinks a code when there's a fault.
Count the blinks and look up the code in your furnace manual (or search "[manufacturer] furnace [X] blinks"). Common codes include:
- 1 blink: normal standby
- 2 blinks: pressure switch open
- 3 blinks: limit switch open
- 4 blinks: limit switch failed
- 5 blinks: ignition lockout
- 6 blinks: flame sensor problem
Step 9: Check the Vents
Go to every room and verify that supply vents are open. If return air vents are blocked by furniture, the furnace may be short-cycling. Free the air paths.
Also check outside: the intake and exhaust pipes for high-efficiency furnaces can get blocked by snow, ice, or bird nests. Walk around your home and verify both pipes are clear.
Step 10: Check the Flame Sensor
This is the most technical step — skip it if you're not comfortable. On electronic ignition furnaces, the flame sensor detects whether the burner lit. If the sensor is dirty, it shuts the furnace off as a safety.
- Turn off power to the furnace at the switch and the breaker
- Open the furnace cover
- Find the flame sensor (small metal rod in the burner assembly)
- Remove it (usually one screw)
- Gently clean it with fine steel wool or emery cloth
- Reinstall and restore power
Cleaning a dirty flame sensor fixes roughly 30% of Fort Wayne "furnace won't start" calls. It's a 15-minute DIY if you're handy.
If None of This Works, Call For Service
After going through all 10 steps, if your furnace still isn't heating, you need a professional. The remaining causes are:
- Failed inducer motor
- Bad ignitor or flame sensor
- Control board failure
- Limit switch failure
- Gas valve failure
- Heat exchanger issue (potentially dangerous — don't DIY)
In Fort Wayne winters, don't wait long — interior temperatures drop fast when it's 15°F outside. Call (260) 255-4551 for 24/7 emergency furnace repair throughout Allen County. Most repairs are completed the same day.