Gas Fireplace Won't Light? 9 Causes, Simple Tests and the Parts That Fix Them
A gas fireplace that won't light almost always comes down to one of nine causes, and most of them cost nothing to fix: a closed valve, an empty propane tank, dead batteries, or a spider in the pilot. This guide works through each one in order of what you see (no spark, a pilot that won't stay lit, clicking with no flame, a pilot that burns but no burner), shows the simple tests you can do yourself, and tells you plainly when to stop and call a gas technician. When it does come down to a part, every one we sell ships with No Sales Tax in any state. Browse all our gas fireplace parts.
Quick answer: why won't my gas fireplace light?
- Check the gas first. The shutoff valve near the fireplace must be open, and on propane the tank can't be empty.
- Check the power and controls. Fresh batteries in the remote and receiver, wall switch set correctly, and the outlet or breaker live on electronic-ignition models.
- Pilot lights but won't stay lit: usually a weak or dirty thermocouple. Pilot stays lit but no flames: usually the wall switch, its wires, or a weak thermopile.
- After summer: air in the line and spider webs in the pilot are the two most common causes.
- Smell gas? Stop. Don't touch any switch. Leave the house and call your gas company from outside.
No Sales Tax in any state, free shipping over $300, and help matching the part to your model: 1-888-866-8206.
Safety first. If you smell gas (a rotten-egg smell), don't light anything, don't flip a light switch or use a phone inside, and don't try to find the leak. Get everyone out and call your gas utility or propane supplier from outside. The tests in this guide are the simple, owner-level ones: batteries, switches, cleaning, and a multimeter reading. Anything that means opening the gas valve, loosening a gas fitting, adjusting gas pressure, or replacing the valve is a job for a licensed gas technician. Let the fireplace cool and turn the gas off before you clean anything, and follow your owner's manual where it differs from this guide.
Own a Heat & Glo, Heatilator or Quadra-Fire? Our Heat & Glo troubleshooting guide covers those fireplaces in detail: IPI flash codes, lockout resets, the DSI electrode and the exact pilot assembly for each model. This page covers the checks that apply to every brand.
Symptom, likely cause and the part that fixes it
| What you see | Likely cause | Part, if it comes to that |
|---|---|---|
| No spark at all when you press the igniter (standing pilot) | Piezo igniter or its wire; electrode cracked or too far from the pilot | Igniter or pilot assembly for your model |
| Spark, but the pilot won't light | Gas off, propane tank empty, air in the line, or a blocked pilot orifice | Usually none: open the gas, purge, clean. Worn-out pilot: 4021-736 pilot (NG), 4021-737 (LP), SE49200 or SE49052 |
| Pilot lights, then goes out when you let go of the knob | Weak or dirty thermocouple, or a small, lazy pilot flame | Thermocouple or pilot assembly for your model |
| Pilot stays lit, but the burner won't come on | Wall switch, remote or wiring; weak thermopile | Remote (RC300, Napoleon remotes), thermopile |
| Electronic ignition: nothing happens, no click | No power, dead batteries or backup pack, wall switch, or a failed module | 2166-347 IPI control module (Hearth & Home brands) |
| Electronic ignition: clicks or sparks, never lights, then stops | No gas, dirty flame sensor, or worn electrode | 501-591 DSI electrode (Heat & Glo DSI) |
| Thermocouple and thermopile test good, still won't hold or won't open | Failed gas valve | SIT 820 Nova valve 14-2632 or SBI 49130 (technician installs) |
First: what kind of ignition does yours have?
Open the lower louver or control door and look at the controls. The fix depends on which of these you have:
- Standing pilot (millivolt). A gas knob marked OFF / PILOT / ON and a red or black push-button igniter. The pilot burns all the time while the fireplace is in use. It needs no electricity, so it works in a power outage. Most older fireplaces, many gas stoves and most vent-free units work this way.
- Intermittent pilot (IPI). No knob to hold. When you hit the switch or remote, a control module sparks the pilot, proves it's lit, then opens the burner. Needs house power or a battery pack.
- Direct spark (DSI). No pilot at all: an electrode sparks the main burner directly and then senses its flame. Also needs power.
The rating plate (usually on a chain behind the lower louver) lists the model and serial number. Have it handy before you order any part.
The 9 causes, in the order to check them
1. The gas is off, or the propane tank is empty
Check the manual shutoff valve on the gas line near the fireplace. The handle should run in line with the pipe. On propane, check the tank gauge: a nearly empty tank may not deliver enough pressure to light the pilot. If your tank ran completely empty, many propane suppliers require a leak check before the system is relit, so call your supplier rather than just refilling and relighting.
2. Air in the line after summer or a tank swap
If the fireplace has been off for months, or the propane tank was just changed, the line fills with air. You'll get a strong spark with no flame. On a standing pilot, hold the knob in at PILOT and keep pressing the igniter for 30 to 60 seconds to purge the line. It can take several tries. If it still won't catch after a few minutes of trying, stop and move on to cause 3 rather than letting gas build up.
3. Spiders, dust or debris in the pilot
Spiders and insects build webs and nests in pilot tubes and orifices over summer. That's why so many fireplaces won't light on the first cold night. With the gas off and the fireplace cold, remove the glass, gently blow out the pilot hood with canned air, and brush away dust and lint around the pilot and burner ports. Don't push a pin or wire into the pilot orifice: it's a precision brass part and is easily enlarged. If the pilot hood is burned, cracked or corroded, replace the pilot assembly.
4. No spark: the piezo igniter or electrode
Turn the room lights down and press the igniter while you watch the pilot. You should see a bright blue spark jump from the electrode to the pilot hood. No spark, or a spark that jumps somewhere else, points to a loose or chafed igniter wire, a cracked ceramic electrode, or a worn piezo button. You can still light most standing pilots with a long lighter while you hold the knob in (check your manual first), which tells you the rest of the system works. On many fireplaces the electrode is part of the pilot assembly, so it's replaced as one piece.
5. Pilot lights but won't stay lit: the thermocouple
A thermocouple is a copper rod that sits in the pilot flame and makes a tiny current. That current holds the gas valve's pilot magnet open. If it's dirty, loose or worn out, the pilot goes out the moment you release the knob.
- Check the flame. The pilot flame should be blue and wrap around the top of the thermocouple. A small, yellow or lazy flame is a dirty pilot (cause 3) or low gas pressure, not a bad thermocouple.
- Clean it. With the gas off and everything cool, polish the thermocouple tip with fine steel wool or emery cloth. Check that its connection at the valve is snug.
- Test it. With a multimeter on the millivolt DC scale, disconnect the thermocouple at the valve and read across it while the pilot heats it. A healthy one makes about 25 to 30 millivolts. Much below about 20 millivolts, replace it.
6. Pilot stays lit, burner won't come on: the thermopile
Many millivolt fireplaces use a second sensor, the thermopile, which makes much more voltage and powers the valve that opens the main burner. A weak thermopile gives you a happy pilot and no fire. Test it at the valve terminals marked TP and TP/TH with the pilot lit and the switch off. Healthy thermopiles usually read well over 400 millivolts; under about 300 to 325 millivolts, most manufacturers call it weak. Check your manual for the exact figures for your valve, and clean the thermopile tip the same way as a thermocouple before condemning it.
7. The wall switch, remote or receiver
This is the most common cause of "the pilot's on but nothing happens," and the easiest to fix.
- Batteries. Replace the batteries in the hand-held remote and in the receiver (usually tucked under the fireplace behind the louver). Receivers often have a three-position switch: ON, OFF and REMOTE. It must be on REMOTE for the remote to work.
- Wall switch. On many fireplaces a wall switch left ON overrides the remote, and a remote won't turn the fire off.
- The jumper test. On a millivolt valve, with the pilot lit, turn the switch off and briefly connect a short piece of wire across the two wall switch terminals on the valve (TH and TP/TH). If the burner lights, the valve and thermopile are fine and the fault is the wall switch, remote receiver or the wires between them. If it still won't light, go back to the thermopile test. Remove the jumper when you're done.
We carry the Heat & Glo RC300 remote thermostat (2166-330), which replaces the transmitter on fireplaces with the RC300-HNG receiver (including the Mezzo, Primo, True and Escape), and a range of Napoleon fireplace remotes. Remotes are model-specific: match the part number on your old remote or in your manual.
8. Electronic ignition (IPI or DSI) won't light
- Power. Check the breaker, the outlet and the plug-in adapter or transformer. Some models also take a battery pack for power outages; if yours runs on batteries, replace them.
- No click at all. With good power, a correctly set switch and a working remote, the control module is the usual suspect. For Hearth & Home fireplaces we stock the 2166-347 IPI control module, which fits IPI models from Heat & Glo, Heatilator and Quadra-Fire (not DSI or standing-pilot systems).
- Clicks but never lights. Usually no gas (causes 1 and 2), a blocked pilot (cause 3), or a gap problem at the igniter.
- Lights, then shuts off after a few seconds. The control board can't "see" the flame. A carboned-up flame sensor or electrode is the classic cause. With the power and gas off, clean the sensor rod lightly with emery cloth. On Heat & Glo DSI fireplaces, the 501-591 DSI electrode replaces a cracked or burned electrode.
Most electronic-ignition modules lock out after a few failed tries. Turn the fireplace off, wait, and turn it back on to reset, then fix the cause rather than resetting it over and over.
9. The gas valve itself
The valve is the last thing to suspect, not the first. Point to the valve only when the thermocouple and thermopile both test good, the jumper test fails, and gas is definitely reaching the fireplace. Valve replacement means opening gas connections, so it's a job for a licensed gas technician, who will also check inlet and manifold pressure with a manometer.
Many gas stoves, inserts and fireplaces use the SIT 820 Nova millivolt valve. The model is printed on the valve body. We stock the SIT 820 Nova gas valve (14-2632), which crosses to SIT 0820844 and ships set for natural gas, convertible to propane, plus its 820 Nova NG conversion kit (14-1031) and the side-mount (14-1024) and top-mount (14-1025) pilot brackets. For Drolet and Osburn gas appliances, the genuine SBI S.I.T. Nova 0820-844 valve (49130) fits the Drolet Excel-Fire, Gtx-I and Ultra-Flame and several Osburn models. Match the SIT number on your old valve before you order.
Gas fireplace parts we stock
Only order a part once a test points to it, and match the part number to your manual or the part you're replacing.
| Part | Fits (per the product listing) |
|---|---|
| Pilot assembly, natural gas (4021-736) | Heat & Glo, Heatilator, Quadra-Fire (model list on product page) |
| Pilot assembly, propane (4021-737) | Heat & Glo, Heatilator, Quadra-Fire |
| SIT convertible pilot, L bracket (SE49200) | Osburn Romance Gas, Drolet Excel-Fire, Gtx-I, Sgs, Ultra-Flame |
| SIT convertible pilot, flat bracket (SE49052) | Osburn Bay Vista, Britannia 31, Cordova, DV36, West Bay 38 and more |
| DSI electrode (501-591) | Heat & Glo DSI models: SL, 6000, 8000, CFX and more |
| IPI control module (2166-347) | IPI models from Heat & Glo, Heatilator, Quadra-Fire |
| RC300 remote (2166-330) | Heat & Glo with the RC300-HNG receiver |
| SIT 820 Nova gas valve (14-2632) | Appliances using the SIT 820 Nova valve |
| S.I.T. Nova valve (49130) | Drolet Excel-Fire, Gtx-I, Ultra-Flame; several Osburn gas models |
| SIT 820 pilot bracket, side (14-1024) / top (14-1025) | SIT 820 Nova pilots |
Won't light after a fuel conversion?
Pilots and burner orifices are sized for one fuel. A fireplace that was converted between natural gas and propane without the full kit, or with the wrong one, often has a tiny or roaring pilot that won't prove properly. Our guide to converting a gas fireplace to propane or natural gas explains what a kit changes, and our Napoleon gas conversion kits are listed by model.
Vent-free fireplaces and stoves: the ODS pilot
Vent-free gas logs, fireplaces and stoves use an oxygen depletion sensor (ODS) pilot. It's built to shut the pilot off when room air runs low on oxygen, and it's also sensitive to drafts, dust and high altitude. If a vent-free unit keeps going out, ventilate the room and clean the pilot before anything else. See our guides on ventless gas stoves, whether ventless gas fireplaces are safe, and ventless vs vented gas logs.
Frequently asked questions
Why does my gas fireplace click but not light?
Clicking means the igniter is working, so the problem is usually gas: a closed shutoff valve, an empty propane tank, air in the line after the off season, or a pilot blocked by dust or spider webs. If it clicks with no visible spark, the igniter wire may be loose or shorted.
Why won't my gas fireplace pilot stay lit?
Most often a dirty or worn thermocouple, which can't hold the valve open once you release the knob. Clean it, make sure the pilot flame wraps around it, and test it with a multimeter. A healthy thermocouple makes roughly 25 to 30 millivolts.
The pilot is lit but the fireplace won't turn on. Why?
Check the remote and receiver batteries and the wall switch first. If those are fine, the jumper test across the TH and TP/TH terminals tells you whether it's the switch wiring or the thermopile and valve.
Why won't my gas fireplace light after summer?
Air in the gas line and spiders or dust in the pilot are the two usual causes. Purge the line by holding the pilot knob and sparking for up to a minute, and clean the pilot with canned air.
Can I fix a gas fireplace myself?
You can safely change batteries, check switches, clean the pilot and thermocouple, and take multimeter readings. Replacing a gas valve, loosening gas fittings or adjusting pressure should be done by a licensed gas technician, and many areas require it by code.
How much does it cost to fix a gas fireplace that won't light?
Often nothing: batteries, an open valve or a cleaning. A part like a thermocouple, pilot assembly or remote costs far less than a service call. A gas valve plus a technician's time is the most expensive common repair.
Related guides
- Heat & Glo fireplace troubleshooting
- Converting a gas fireplace to propane or natural gas
- Ventless gas stoves
- Are ventless gas fireplaces safe?
- Ventless vs vented gas logs
- Gas fireplace parts
Not sure which part fits? Email info@stovesource.com or text 1-888-866-8206 with the model and serial number from your rating plate and we'll confirm it. Every part ships with No Sales Tax in any state, and orders over $300 ship free.