If your gas fireplace won’t turn on, the cause is almost always one of six things: the gas valve is closed, the pilot is out, the batteries in the ignition module or remote are dead, the wall switch has failed, the thermopile has weakened past the point where it can hold the gas valve open, or the pilot orifice is blocked. Most of those you can check yourself in about ten minutes. Below is the order to check them in, the symptom that points to each one, and the point where you should stop and call a professional. Gas fireplace service in San Antonio starts from $198.
First: the safety check that comes before any troubleshooting
If you smell gas — a rotten-egg or sulfur odor — stop. Do not flip the switch, do not press the igniter, do not use a lighter, and do not touch light switches or your phone indoors. Get everyone out of the house, then call CPS Energy or 911 from outside. Nothing below applies until that is ruled out.
The same goes if your carbon monoxide alarm has sounded, or if anyone has had unexplained headaches, nausea, or drowsiness that improves when they leave the house. Gas appliances that burn or vent incorrectly can produce carbon monoxide, and it gives no warning of its own — more on that in carbon monoxide and your chimney.
No gas odor and no alarm? Work through the checks below in order — cheapest and most common first.
1. Is the gas actually turned on?
Obvious, and still the most common cause after a long San Antonio off-season. Two shutoffs to check:
- The key valve near the fireplace — often a small square key socket in the floor or wall a few feet away, or a lever valve behind the lower grille. Someone may have closed it in spring and forgotten.
- The gas control valve inside the firebox, behind the lower louvered panel, with a knob marked OFF / PILOT / ON. On OFF or PILOT, the main burner will not light no matter what the switch does.
On propane, check the tank level too — a fireplace is often the last appliance anyone thinks of when a tank runs low.
2. Which ignition system do you have?
This determines everything that follows, so identify it before going further.
Standing pilot (millivolt)
A small pilot flame burns continuously and heats a thermopile, which generates a tiny current that holds the main gas valve open. These need no household power — which is why they work in an outage — but they go out on their own if a draft, a dirty orifice, or a weak thermopile interrupts them.
Electronic / intermittent pilot ignition (IPI)
No flame between uses: when you call for heat, a module sparks the pilot, which lights the burner. These need power — usually AA or D batteries in a pack inside the firebox, or a plugged-in transformer, plus batteries in the remote.
3. Dead batteries — the most common electronic-ignition failure
If you have electronic ignition and nothing happens at all — no click, no spark — replace the batteries before doing anything else. There are frequently two sets: one in the handheld remote, and one in a battery pack tucked behind the lower panel of the firebox. The pack is the one people forget, because it’s out of sight and only gets touched every couple of years.
Replace both, then try again. It’s the first thing we check on an electronic-ignition fireplace that does nothing at all, and it’s worth ruling out before you book anyone.
4. The wall switch
On a millivolt fireplace the wall switch carries a tiny current, and over years of sitting idle its contacts corrode until they no longer connect. The fireplace is fine; the switch is the failure. The telltale sign is a pilot burning steadily while the switch does nothing at all. Confirming it means opening the switch and testing the low-voltage wiring, so unless you’re comfortable with that, just note the symptom — it’s a two-minute diagnosis and an inexpensive part for a technician who carries them.
5. The pilot lights, then goes out
The classic thermopile symptom: you hold the control knob down, the pilot lights and stays lit while you hold it, then dies within seconds of letting go. The pilot isn’t producing enough millivoltage to keep the safety valve open on its own. Usual reasons:
- The thermopile has aged out — they weaken over years until they fall below the threshold needed to hold the valve. A wear part, not a defect.
- The pilot flame is small, lazy, or yellow instead of a crisp blue flame enveloping the sensor tip, so it can’t heat it properly.
- The thermopile is soot-covered or out of position, and the flame isn’t hitting it where it should.
6. It clicks and sparks but won’t catch
Spark but no flame usually means a blocked pilot orifice or an electrode that’s fouled or drifted out of alignment with the pilot hood. The pilot opening is a pinhole; it doesn’t take much to plug it.
This is where a San Antonio quirk earns its mention. A gas fireplace here sits unused from roughly March through November — nine idle months for dust to settle on the burner, for spiders and mud daubers to build inside pilot tubes and burner ports (a well-known nuisance with any gas appliance left idle), and for a bird or squirrel to take an interest in the vent termination on the roof. If the vent cap is compromised, that’s its own fix: see animal and bird removal.
When to stop and call a professional
Homeowner territory ends at batteries, valve position, and looking at the pilot flame. Call someone if:
- You smell gas at any point — leave first, call from outside
- The pilot won’t stay lit once you’ve confirmed the gas is on
- The glass is sooting up, or the flames are tall, lazy, and yellow rather than blue-based
- You hear a delayed whoosh when the burner finally catches
- The fireplace shuts itself off during operation
- Anything requires touching the gas line, valve body, or fittings
That last one is a hard line. Gas piping is licensed plumbing work — not something to try, and not something we do either. Our work stops at the appliance.
What a Sweeppy gas fireplace service covers
Our gas fireplace repair and service starts from $198 and covers the appliance side:
- Tune-up, cleaning, and inspection of the firebox, burner, and pilot assembly
- Gas log service — cleaning and repositioning, since logs out of place cause sooting
- Ignition and pilot repairs: thermopile and thermocouple replacement, pilot cleaning, electrode adjustment, switch and battery-pack issues
- Checking the venting for blockage and proper draft
What we don’t do: gas line work, plumbing, or anything behind the shutoff valve. If that’s what your fireplace needs, we’ll say so plainly and you’ll call a licensed gas plumber instead. Nathan, the owner, is on every job — no subcontractors, and no upsell waiting at the end. If you also have a wood-burning fireplace, that’s a separate service: a chimney sweep is $144 flat and includes a Level 1 inspection.
Get ahead of the first cold front
The best time to find out your fireplace won’t light is a warm week in late summer — not the first genuinely cold evening in San Antonio, when every fireplace company in town is booked out. NFPA 211 recommends that chimneys, fireplaces, and vents be inspected annually, and a gas fireplace is no exception just because there’s no creosote involved. Test yours now, while a repair is a scheduling question rather than an emergency. For the wider seasonal picture, see our San Antonio chimney safety guide.
Frequently asked questions
Where is the battery pack on a gas fireplace?
On most electronic-ignition models it’s behind the lower louvered panel of the firebox — a small plastic holder for AA or D cells. It’s separate from the batteries in your remote, and it’s the set homeowners most often overlook. If the fireplace does nothing at all when you call for heat, replace both before assuming anything is broken.
Does a gas fireplace produce creosote?
No — creosote comes from burning wood, so there’s nothing to sweep in the traditional sense. That doesn’t make a gas fireplace maintenance-free: burners and pilot assemblies collect dust and insect nests over an idle summer, gas logs shift and cause sooting, and the vent still has to be clear and drafting correctly.
Can I light my gas fireplace with a match?
Only if it’s a standing-pilot model designed for manual lighting, and only by following the lighting instructions printed on the label inside the firebox. Never hold a flame to an electronic-ignition unit, and never try to light anything after gas has been flowing — leave the area and let it clear first.
Why does my gas fireplace shut off by itself while running?
Shutting down mid-use points to a safety device doing its job — commonly a weakening thermopile that can no longer hold the valve open once conditions change, or a vent or draft problem tripping a safety switch. Because the shutoff is a symptom of something upstream, this one isn’t worth repeated restarts. Have it diagnosed before using the fireplace again.
Fireplace not cooperating? Call Sweeppy at (210) 418-9810. Owner-operated, licensed and insured, 4.8 stars on Google, serving San Antonio, Stone Oak, Helotes, Boerne, Alamo Heights, and the surrounding areas — same-day appointments available.
