Furnace clicks but won't ignite
The hot-surface ignitor (a glowing element that lights the gas) wears out every 5–7 years. Replacement runs $150–$300 installed. This involves gas connections — not a DIY job.
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Troubleshooting Guide · Marion, Ohio
Before you call for a service visit, walk through these common causes. Most no-heat calls we get in Marion have a simple fix you can do yourself in under 20 minutes.
8-step guide
Work through these steps in order. Each one takes 1–3 minutes and covers the most common reasons furnaces stop working in Marion and central Ohio.
Make sure your thermostat is set to HEAT (not OFF, COOL, or FAN ONLY) and the target temperature is at least 3–5°F above the current room temperature. If the thermostat display is blank, replace the batteries first.
Tip: Also check for a programmed schedule override. “Away” or “Eco” modes on smart thermostats can prevent the furnace from firing.
Every furnace has a dedicated power switch that looks like a regular light switch, mounted on the furnace itself or on a nearby wall. This is the single most common reason for a “dead” furnace — someone bumped it off during storage or laundry.
Look for it on the side of the furnace, on the ceiling above it, or on the wall near the basement stairs.
Go to your electrical panel and find the breaker labeled HVAC, Furnace, or Air Handler. A tripped breaker sits in the middle position (not fully on or off). Flip it fully OFF, then back ON.
If the breaker trips again immediately, stop and call PJ's — repeated tripping means a short circuit or failing motor that needs professional diagnosis.
A severely clogged filter restricts airflow so much that the furnace overheats and triggers the high-limit safety switch, shutting everything down. Pull the filter out (usually between the return duct and the furnace) and hold it to a light. If you can't see through it, replace it immediately.
After installing a fresh filter, wait 10 minutes for the high-limit switch to cool and reset before trying to restart the furnace.
If you have a gas furnace, verify the gas valve is open. The valve handle should be parallel to the gas line (perpendicular means closed). Also check: are other gas appliances working (stove, water heater)? If nothing gas-powered works, the issue may be with your gas supply or meter — contact your gas company.
If you smell gas (rotten egg odor), leave the house immediately, do NOT flip any switches, and call 911 or your gas company from outside.
If your furnace is 90%+ efficiency (look for PVC vent pipes instead of a metal chimney), it produces condensation. A clogged condensate drain triggers a safety switch that shuts the furnace off completely. Find the small drain tube or pan at the bottom of the furnace and check for blockages or standing water.
You can clear a clogged drain line by pouring a cup of white vinegar through it, or use a wet/dry vac on the other end.
Most modern furnaces have a small LED light visible through a sight glass on the front panel. The LED blinks a pattern that tells you what's wrong. Note the number of blinks and check the diagnostic chart on the inside of the furnace access door.
Common patterns: 1 blink = normal operation · 2 blinks = external lockout · 3 blinks = pressure switch error (check exhaust vent for blockage) · 4 blinks = open high-limit (check filter) · 5+ blinks = flame/ignition failure (call a pro).
Turn the furnace power switch OFF, wait 30 seconds, then turn it back ON. This clears temporary fault codes on the control board. Give the system 2–3 minutes to go through its full startup sequence (inducer motor → ignitor glow → gas valve opens → blower starts).
If the furnace starts but shuts off again within a minute, the problem is likely a dirty flame sensor — a common and inexpensive repair that requires a technician.
Know the signs
If you've worked through all 8 steps and your furnace still won't start, the problem is internal. Here's what likely needs a technician.
The hot-surface ignitor (a glowing element that lights the gas) wears out every 5–7 years. Replacement runs $150–$300 installed. This involves gas connections — not a DIY job.
Call nowAlmost always a dirty flame sensor. Carbon buildup prevents it from detecting the flame, so the control board kills the gas. A quick clean or replacement ($100–$200) fixes it.
The blower motor is working but the burners aren't firing. This usually points to a gas valve issue, failed control board, or faulty pressure switch. Requires professional diagnosis.
If your furnace is frequently needing repairs and is past its expected lifespan, replacement may be more cost-effective. Modern furnaces are 95–98% efficient vs. 80% for older units.
Common questions
The most common reasons: tripped circuit breaker, furnace power switch bumped to OFF, dead thermostat batteries, clogged air filter triggering the high-limit switch, or a faulty ignitor. Work through the power and filter checks first — they solve about 60% of no-start calls.
If you hear clicking but the furnace doesn't fire, the ignitor is likely worn out. Modern furnaces use a hot-surface ignitor that glows red to light the gas. These wear out every 5–7 years. Replacement costs $150–$300 installed. This is not a DIY repair — it involves gas connections.
This is usually a dirty flame sensor. The flame sensor detects whether the burner is lit. When coated with carbon, it can't sense the flame, so the control board shuts off the gas. A technician can clean or replace the sensor in about 20 minutes — typically $100–$200.
The LED on your furnace's control board blinks a diagnostic code. Common patterns: 1 blink = normal, 2 = external lockout, 3 = pressure switch error (check exhaust vent), 4 = open high-limit (check filter), 5+ = flame/ignition failure. Check the chart on the inside of the furnace access panel door.
Most furnace repairs in Marion cost $150–$500. Common repairs: ignitor replacement ($150–$300), flame sensor cleaning ($100–$200), blower motor ($300–$600), control board ($300–$600). PJ's provides a clear estimate before starting work. For furnaces older than 15–20 years with frequent repairs, replacement may be more cost-effective.
Related services
Full furnace diagnosis and repair — ignitors, flame sensors, blower motors, control boards. Same-day service available.
Prevent breakdowns before they happen. Our fall tune-up catches worn ignitors and dirty sensors early.
Blank display, wrong temperature, or unresponsive controls? Our thermostat guide walks you through it.
What our customers say
★★★★★“Woke up to a cold house on a Saturday morning. PJ’s came out within two hours, found the power switch had been bumped off by my kid playing in the basement. No charge. That’s the kind of honest service you don’t find anymore.”
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Tips and guides from our team:
★★★★★“Our furnace was clicking but wouldn’t fire. PJ’s diagnosed a bad ignitor, had the part on the truck, and fixed it in 30 minutes. Fair price and explained everything so we’d know what to check next time.”
If you've tried the steps above and your furnace still won't start, fill out the form and we'll call you back — usually within the hour. For emergencies, call directly.
(740) 382-6141