Common Fireplace Problems and How to Fix Them
Most common fireplace problems have an ordinary cause and a clear fix. A gas pilot that keeps going out is usually a worn safety sensor, smoke in the room is usually a closed damper or a cold or blocked chimney, and cold air when the fire is off is a damper that no longer seals. Some of these you can check yourself in five minutes; anything involving gas or the inside of the chimney is a job for our service team. Here are the problems we see most around Downers Grove, gas first and then wood.
A pilot light that will not stay lit
The pilot is the small flame that lights the main burner of a gas fireplace. In that flame sits a thermocouple, a sensor the size of a pencil tip that makes a tiny electric current when it is hot, and that current tells the gas valve it is safe to stay open. When the thermocouple is dirty, cracked or worn out after years of heating and cooling, the valve shuts the gas off, which is exactly what it is designed to do.
Check that the shut-off valve on the gas line is fully open and hold the pilot button down for the full time the manual gives. If it goes out again, stop there. Replacing a thermocouple means working on the gas assembly, never a do-it-yourself job. We carry the common parts, so most pilot faults are fixed in one visit.
Nothing happens when you flip the switch
Start with the basics: the supply valve on the gas line near the fireplace is open when the handle runs in line with the pipe; the remote and the receiver box under the unit both need fresh batteries; and no breaker has tripped.
If the basics are fine, it is usually one of two parts. The igniter makes the spark that lights the pilot, and it often fails intermittently first. The thermopile is a larger cousin of the thermocouple that powers the main valve, so when it weakens the pilot looks fine but the burner never comes on. Both are tested with a meter and replaced in one visit. Book a service appointment and we will tell you which part it is before any work begins.
You smell gas
Natural gas has a rotten-egg smell added to it so that a leak gets noticed. Treat that smell as an emergency. Do not flip light switches, unplug anything or use a phone inside the house. Leave, and call your gas utility from outside; for most of DuPage County that is Nicor Gas. Then call us.
Once the utility has made the house safe, we inspect the fireplace and its connections to find the source, usually a loosened fitting, a worn valve seal or a corroded connector. Do not use the fireplace again until the leak has been repaired.
Yellow or lazy flames on a gas fireplace
Gas burns blue when it burns cleanly. Many vented gas log sets are designed to burn with tall yellow flames, and on those the color is intended. If your flames have turned yellow, lazy or sooty when they were not before, the gas is not burning completely, and incomplete burning makes carbon monoxide, which you cannot see or smell.
Stop using it and have it looked at. The usual causes are a dirty burner, logs placed where they block the flame or dust in the air openings, all quick for us to put right. Every home with a gas appliance needs a carbon monoxide alarm near the bedrooms; Illinois law requires one.
Smoke backing into the room
Smoke in the room has four usual causes.
The damper, the metal plate in the throat of the chimney that you open to let smoke out. Make sure it is fully open before you light anything. If it sticks or only opens part way, it needs cleaning or repair.
A cold chimney. After the fireplace has sat unused, the cold air in the flue sinks into the room rather than rising. On a wood-burning fireplace, warm it first: light one end of a rolled newspaper and hold it up near the open damper for a minute until you feel the draft pull upward, then light the fire. Never do this in a fireplace with a gas log set.
A blocked or narrowed flue. Creosote from past fires narrows the passage, and squirrels, raccoons and birds nest in a chimney that sits idle all summer. If the damper is open and the flue is warm and the smoke still comes in, the chimney needs to be swept and inspected. Our chimney cleaning and repair service clears the flue and checks the structure on the same visit.
A tight house. Range hoods, bathroom fans and dryers pull air out of the home, and the fireplace becomes the easiest way for it to get back in, bringing smoke with it. Turn the fans off and crack a window near the fireplace. A fire that is hard to light or keep going is usually the same draft trouble, or wet wood.
Cold air coming in when the fireplace is off
Cold air at the hearth with no fire lit means the damper is not sealing. Throat dampers in older masonry fireplaces warp and rust. In a wood-burning fireplace that is not in use, an inflatable draft stopper pushed up into the throat is a fair stop-gap — never with a gas log set or a pilot light, and take it out before the next fire. The real fix is a damper repair, or a top-sealing damper that closes the top of the chimney with a gasketed lid. We repair and replace both as part of our chimney service.
Cracks in the firebox
The firebox is the chamber the fire sits in, lined with firebrick in a masonry fireplace and with heat-resistant panels in a factory-built one. Both crack over time from heat. Hairline cracks in the mortar joints can be filled with heat-resistant fireplace mortar. Wider cracks, loose bricks or a crack that goes through to the back wall let heat reach the framing behind the fireplace, so do not use it until it has been inspected.
Creosote and soot
Creosote is the tarry residue left when wood smoke cools and condenses inside the flue. It burns, and a thick layer is what feeds a chimney fire. Black flakes in the firebox, a shiny glaze up the flue or a smoky smell in the house on a humid summer day all mean it is time for a sweep. Seasoned wood, hot fires rather than smoldering ones and a yearly sweep keep it to a minimum. If you ever hear a roaring from the chimney during a fire, that is a chimney fire: get everyone out and call 911 from outside.
A light haze on fireplace glass is normal and comes off with a cleaner made for fireplace glass. Heavy or fast-returning soot points to logs in the wrong place on gas, or wet wood and a poor draft on wood, and is worth an inspection.
Common fireplace problems at a glance
| Problem | Check this first | Call us when |
|---|---|---|
| Pilot will not stay lit | Valve open; pilot button held the full time | It goes out again |
| No ignition at all | Valve, batteries, breaker | The basics are fine |
| Smell of gas | Nothing. Leave and call the utility | After the utility has made the house safe |
| Yellow or lazy gas flames | Whether your log set is meant to burn yellow | The color has changed or there is soot |
| Smoke in the room | Damper open, flue warmed, fans off | It still smokes |
| Cold draft when off | A temporary draft stopper | You want it fixed for good |
| Cracks or creosote | How big, how thick | Anything beyond a hairline or a light haze |
When to call
Repairs are quicker before the cold sets in, when every service schedule in DuPage County fills up. If your fireplace has shown any of these symptoms, or has not been serviced in more than a year, book now rather than in January. If an old unit is not worth another repair, the showroom has gas fireplaces, inserts and log sets on display, so you can see the size of a replacement before you decide.
Common questions
Why does my gas fireplace pilot keep going out?
On a standing-pilot unit, usually a worn or dirty thermocouple, the sensor in the pilot flame that tells the valve it is safe to stay open; electronic-ignition units have their own sensors and controls. It is a quick repair for us and not one to attempt yourself.
Can I fix a gas fireplace myself?
You can check the valve, the batteries and the breaker, and clean the glass. Everything past that involves the gas assembly or the vent and belongs to us. A badly adjusted burner makes carbon monoxide.
What should I do if I smell gas near the fireplace?
Leave the house without touching switches or phones inside, call your gas utility from outside, then call us. Do not use the fireplace again until the leak has been repaired.
How often should a fireplace be inspected?
Once a year, gas and wood alike. The national fire-safety standard, NFPA 211, recommends an annual chimney inspection, and a gas unit needs its burner, pilot, connections and vent checked on the same schedule.
Talk it through in the showroom
A Fireplace Store and More is at 1202-B 75th Street in Downers Grove, open seven days. Bring a photo of the wall or the opening, or just the question. We size it, quote it in writing and install it with our own team. Book a showroom or in-home visit, ask for a written estimate, or call (630) 241-1919.