Furnace not heating, short cycling, or making a noise it did not make last winter? We repair gas furnaces across Los Angeles and the San Fernando Valley, usually same day. Your $99 diagnostic is credited to the repair, and you get a written estimate before any work starts.
- Call (818) 660-1062 for same-day furnace repair
- Book online, 24 hours a day
- Repair it now: gas furnace and heater repair in Los Angeles
- Stop it happening again: heating and AC maintenance plans
Stop and read this first if you smell gas
A rotten egg or sulfur smell near your furnace means a possible gas leak. Do not flip any switches, do not light anything, and do not use your phone inside the house. Get everyone out, then call the gas company or 911 from outside. Call us once the leak is shut off and we will handle the furnace side.
The same applies if your carbon monoxide alarm sounds. Get out first, call second.
The most common gas furnace problems
1. The furnace runs but blows cold air
Usually the burners are not staying lit. The most frequent causes are a dirty flame sensor, a failing hot surface igniter, or a gas valve that is not opening. A clogged filter can also cause the limit switch to trip and shut the burners down while the blower keeps running.
Check yourself: the air filter, and that the thermostat is set to Heat rather than Fan On.
2. The furnace will not turn on at all
Start with the simple things: the thermostat batteries, the furnace switch (it looks like a light switch near the unit and gets flipped off by accident), the breaker, and the furnace door panel, which has a safety switch that cuts power if the panel is not seated properly.
If all of those are fine, it is usually the control board, a blown low-voltage fuse, or the transformer.
3. The furnace turns on and off every few minutes
This is short cycling, and it is the symptom most worth taking seriously. Common causes are a clogged filter restricting airflow, a dirty flame sensor, a failing limit switch, a blocked flue, or a furnace that is simply oversized for the house.
Short cycling burns more gas, wears out components faster, and in some cases points at an overheating problem that can crack a heat exchanger. Do not ignore it.
4. The blower never shuts off
Either the thermostat fan setting is on On instead of Auto, or the fan limit switch has failed. If the thermostat is set correctly, it is a repair.
5. Loud or unusual noises
The sound tells you a lot. Screeching or squealing is usually blower motor bearings. Scraping metal is often the blower wheel hitting the housing. Rumbling that continues after the burners shut off can mean dirty burners. A loud bang or boom on startup is delayed ignition, where gas builds up before lighting, and that one needs attention quickly.
6. Burning or musty smells
A dusty burning smell for the first ten minutes of the season is normal. A burning plastic or electrical smell is not, and you should shut the furnace off at the switch and call. A musty smell usually points at the filter or the ductwork rather than the furnace itself.
7. The flame is yellow instead of blue
A healthy gas flame burns steady blue. Yellow or orange flame means incomplete combustion, which produces carbon monoxide. Turn the system off and get it inspected before running it again.
8. The gas bill jumped and nothing else changed
A furnace losing efficiency works longer to hit the same temperature. Common culprits are a clogged filter, dirty burners, leaking ducts, or a system near the end of its life.
What gas furnace repair costs
Most gas furnace repairs come down to one of a handful of parts: the hot surface igniter, flame sensor, pressure switch, limit switch, draft inducer motor, gas valve, control board, or blower motor. Which one it is changes the price considerably, so we diagnose first and quote second.
Our $99 diagnostic is credited to the repair when you approve the work, and you get a written price before anything starts. No work happens without your sign-off.
Repair it or replace it?
A rough guide that holds up well in practice:
- Under 10 years old: repair is almost always the right call.
- 10 to 15 years: depends on the repair. If it is a $200 part, fix it. If it is a major component, weigh it against a new system.
- Over 15 years: lean toward replacement, especially if it has needed repairs two years running.
- Cracked heat exchanger at any age: replace. This is a carbon monoxide risk and it is not worth repairing.
If you are weighing it up, see furnace and heat pump replacement in Los Angeles, or read our breakdown of furnace repair vs replacement. We will tell you honestly which one makes sense. If a $300 repair buys you five more winters, we will say so.
How to avoid the next breakdown
Most of the failures above are preventable, and almost all of them start with airflow.
- Change the filter. Every one to three months. A clogged filter causes short cycling, limit trips, and overheating, and it is the single most common root cause we find.
- Book an annual service before the cold arrives. A furnace that has not been inspected in over a year is far likelier to fail on the first cold night, which is also the hardest night to get a technician.
- Test your carbon monoxide alarms. Replace the batteries twice a year. Gas furnaces make CO a real risk, and it has no smell or color.
- Keep the area around the furnace clear. No boxes, paint, or cleaning products near the air intake.
Annual service also keeps most manufacturer warranties valid. Many warranties require documented professional servicing, and skipping it can leave you paying full price for a repair that would have been covered. See our heating and AC maintenance plans in Los Angeles.
Same-day gas furnace repair across Los Angeles
We repair gas furnaces, wall heaters and heat pumps throughout Los Angeles and the San Fernando Valley, including Woodland Hills, Northridge, Encino, Tarzana, Sherman Oaks, Calabasas, Burbank and Thousand Oaks. Licensed, EPA certified technicians, serving Los Angeles since 2010.
Call (818) 660-1062 or book online and we will get someone out to you.
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