A gas oven that will not heat usually shows up at the worst moment: the turkey is ready to go in, the oven clicks or glows, and nothing happens. The good news is that most “gas oven not heating up” problems come down to a short list of causes, and one simple test (watching the igniter) tells you a lot before you pick up the phone.
This guide walks through what you can safely check yourself, what each symptom points to, and where gas work stops being a DIY job in Ontario. If you have an electric oven, or you are not sure which you have, our general guide why is my oven not heating up? covers the electric side too.
Safety First: If You Smell Gas
Do not troubleshoot an oven that smells of gas. The smell (often described as rotten eggs or sulphur) is added to natural gas on purpose so you notice leaks.
- Do not turn any switches, lights or appliances on or off, and do not use a lighter or match.
- Leave the home with everyone, leaving the door open behind you if you can.
- Once outside and away from the building, call your gas utility’s emergency line or 911. In Toronto that is Enbridge Gas; their emergency number is printed on your gas bill and on the Enbridge website.
- Do not go back inside until the utility or emergency crew says it is safe.
A faint, brief whiff right as the burner lights can be normal on some ovens. A smell that lingers, or that appears while the oven is off, is not. When in doubt, treat it as a leak.
How a Gas Oven Lights
Most gas ovens and ranges sold in the last few decades use a hot surface igniter, sometimes called a glow bar. Understanding how it works makes the rest of this guide much easier:
- You set a temperature. The control (a thermostat on older models, an electronic board on newer ones) sends power to the igniter.
- The igniter heats up until it glows bright orange.
- Power for the igniter also flows through the oven safety valve (also called the gas valve). That valve only opens once enough current is flowing, which only happens when the igniter is hot enough to light gas.
- The valve opens, gas flows to the bake burner, and the hot igniter lights it.
- When the oven reaches temperature, the control cuts power, the valve closes and the flame goes out. It cycles back on as the oven cools.
The key point: the safety valve and the igniter work as a pair. An igniter can glow and still be too weak to open the valve. That is the most common reason a gas oven will not heat, and it is why “my igniter is glowing but there’s no flame” is such a common search.
Some older ranges use a standing pilot or a spark igniter instead. If you see a small blue flame that stays lit all the time, or you hear rapid clicking when the oven is calling for heat, you have one of those systems. The supply and control checks below still apply.
Quick Checks Before Anything Else
These take a few minutes and solve more calls than you might expect:
- Is the cooktop working? Try a top burner. If none of the burners light, the problem is likely the gas supply to the whole appliance, not the oven itself.
- Is the oven getting power? Gas ovens still need electricity for the igniter, clock and controls. If the display is dark, check that the range is plugged in and look for a tripped breaker or blown fuse.
- Is a lock or timer set? Control lock, Sabbath mode, a delayed start or an active self-clean lock can all keep the oven from heating. Check the display and your owner’s manual for how to clear them.
- Was the oven just self-cleaned? Self-clean runs very hot and is a common time for a weak igniter or a control fuse to finally fail. If the oven quit right after a clean cycle, mention that to your technician.
- Is the right mode selected? Broil uses a different burner (often at the top of the oven or in the drawer below). If broil works but bake does not, that narrows things down nicely.
The Igniter Glow Test
This is the single most useful check you can do yourself, and you do not need to take anything apart.
- Remove the oven racks. On most models you then lift out the oven floor panel (it usually lifts or slides out, sometimes after removing one or two screws at the back) to see the bake burner and igniter underneath. If your floor panel is not designed to come out, look through the slots in the floor instead.
- Set the oven to bake at a normal temperature, such as 350°F.
- Watch the igniter (a flat or round grey bar near the burner) from a safe distance. Do not touch it; it gets extremely hot and is also fragile.
Here is what you might see, and what it usually means:
- It glows bright orange and the burner lights within a minute or two. Ignition is fine. If the oven still does not reach temperature, look at the temperature sensor and control section below.
- It glows, but the burner never lights. The most likely cause is a weak igniter that cannot draw enough current to open the safety valve. Less often, the safety valve itself has failed. A technician can tell the two apart with a meter in a few minutes.
- It glows a dull orange or takes a very long time, then lights with a small “whoomph”. This is the classic sign of a weakening igniter. Delayed ignition lets gas build up before it lights, so do not keep using the oven like this.
- It does not glow at all. The igniter may have burned out, or it is not getting power because of a wiring, control board or thermostat fault.
- The flame lights, then goes out after a few seconds. Often a weak igniter as well, because the valve closes when current drops. A supply or valve problem is also possible.
Turn the oven off when you are done, and let everything cool before you put the floor panel back.
Gas Valve, Safety Valve and Supply Checks
There are a few supply-side issues an owner can check without opening any gas fittings:
- Shut-off valve. Most ranges have a manual shut-off on the gas line behind or below the unit. If the range was recently moved, cleaned behind or installed, make sure that valve is fully open (the handle runs in line with the pipe). Do not loosen or tighten any fittings.
- Kinked flex line. Pushing a range back against the wall can kink the flexible connector. If you can see a sharp bend, do not try to straighten a gas line yourself; have it inspected and replaced.
- Other gas appliances. If your furnace, water heater or other gas appliances have also stopped, the issue is with the home’s supply, so contact your gas utility.
- Burner ports. Spills, grease or cleaning residue can block burner ports and give you an uneven or weak flame. Wiping the burner area once the oven is cool is fine; do not poke wire into the gas orifice.
The oven safety valve, pressure regulator and the gas connections are not owner parts. Replacing or adjusting them involves opening the gas system, which brings us to the legal side further down.
Temperature Sensor and Control Faults
If the burner lights normally but the oven runs cold, will not reach the set temperature, or overshoots, the issue is usually in the control side rather than the gas side:
- Temperature sensor. Many electronic ovens use a thin probe on the back wall of the oven cavity. If it is bent against the wall, damaged or reading wrong, the control may shut the burner off too early. A failed sensor often throws an error code; see our GE oven error codes guide for an example of how brands report these faults.
- Calibration. If the oven heats but bakes noticeably cooler than the dial or display says, check it with an oven thermometer on the middle rack after a full preheat. Many models let you adjust calibration through a settings menu; your owner’s manual explains how.
- Control board or thermostat. A board relay or older mechanical thermostat can fail to send power to the igniter. These are electrical repairs and are best diagnosed with a meter.
- Door seal and hinges. A torn gasket or a door that does not close fully lets heat escape, making preheating slow and baking uneven.
Why Gas Repairs Need a TSSA-Certified Technician in Ontario
In Ontario, work on gas appliances is regulated by the Technical Standards and Safety Authority (TSSA). Installing, servicing or repairing gas-fired appliances must be done by a TSSA-certified gas technician working for a registered contractor. That includes replacing an oven safety valve or regulator, and any work that opens a gas connection.
This is not just paperwork. A gas repair done incorrectly can leak, cause delayed ignition, or produce carbon monoxide. A certified technician checks for leaks after the repair, confirms the burner lights and burns properly, and makes sure the appliance is safe to leave running.
What you can safely do as an owner: the quick checks, the glow test, cleaning, calibration from the menu, and checking the power and the manual shut-off valve position. What should go to a professional: anything that involves the gas valve, gas line, regulator, wiring behind panels, or a smell of gas.
Also keep a working carbon monoxide alarm near sleeping areas. Ontario requires CO alarms in homes with fuel-burning appliances, and they are an important backstop with any gas range.
Signs It Is Time to Call a Pro
- The igniter glows but the burner does not light, or it lights late with a loud whoomph.
- The igniter does not glow at all and the oven has power.
- You smell gas at any point (leave first, then call the gas utility or 911).
- The flame is yellow, lazy, sooty or lifting off the burner instead of mostly blue.
- The oven shows an error code that returns after a power reset.
- The oven quit during or right after a self-clean cycle.
- Your CO alarm has gone off while the oven was running.
When you call, have your model and serial number ready (usually on a label around the oven door frame, inside the storage drawer, or on the back of the range), along with what you saw during the glow test. That helps a technician bring the right igniter or valve the first time.
Book Before the Holiday Rush
Ovens work hardest from Thanksgiving through the December holidays, and that is when weak igniters tend to give out. If yours has been slow to light, lights with a bang, or takes much longer than it used to preheat, it is worth getting it looked at now rather than on the morning of a big meal. Our checklist on getting your oven ready for the holidays covers the other things worth checking before guests arrive.
I-Fix Appliance Repair handles oven and stove repair for gas and electric ranges across Toronto, North York, Scarborough and Etobicoke. If you are on the west side of the city, see our appliance repair in Etobicoke page, or reach us through the contact form to book a visit.