No-heat is the call that defines a SoCal winter: the furnace ran fine in March, sat idle all summer, and now refuses to fire on the first cold night in November. The good news is the failures are predictable and most are inexpensive single-visit fixes. This page is the Trane-specific companion to our general furnace repair service and our Trane furnace repair page. Common failure modes have dedicated guides: ignitor replacement, flame sensor, won’t ignite, limit switch, pressure switch, inducer motor, and gas valve.
Why a Trane furnace stops heating
From years of Trane and American Standard no-heat calls across SoCal, the causes cluster in a predictable order:
- Hot-surface ignitor wear — the most common no-heat fault. The silicon-nitride ignitor degrades over hundreds of cycles and eventually cracks or no longer reaches ignition temperature. Symptom: blower and inducer run, no flame. $245–$485 installed.
- Flame-sensor fouling — the furnace lights, then shuts down after 3–7 seconds because a dust-coated sensor cannot prove flame to the board. Clean or replace, $185–$295.
- Draft / pressure-switch fault — the inducer cannot prove safe venting, so ignition never starts. Often a clogged condensate trap or a weak inducer on an XV80 or XV95.
- Integrated control-board failure — frequently after a Santa Ana voltage transient. $480–$950.
- Gas-valve failure — less common, $385–$685.
- Blower motor failure on the air-handling side, $480–$890.
Read the Trane fault code first
How a Trane furnace reports a fault depends on its generation, and knowing which you have saves a wrong turn. A conventional furnace flashes a diagnostic LED on the control board behind the lower door — a slow blink is normal standby, a fast blink is a normal call for heat, and a repeating red flash pattern is a fault you count. A communicating system (the S9V2 or a modulating furnace paired to an XL850 or XL1050 ComfortLink II control) shows an alphanumeric “Err” code on the thermostat instead. Either way the code narrows the fault to a subsystem — ignition, airflow and limit, or pressure and venting — but it is a starting point, not a diagnosis. The full reference is on our Trane error codes page. Do not keep resetting a furnace that locks out repeatedly; a lockout is a safety response, not a glitch.
The first-cold-night pattern
An LA-basin furnace runs 200–400 hours a year against 1,500-plus in a cold climate, and that long idle stretch from April to October is where no-heat breeds. Dust settles on the flame sensor, the ignitor ages without being exercised, inducer bearings stiffen, and control-board capacitors drift. The first November cold snap asks an untouched furnace to fire cleanly, and the predictable failures surface all at once. Mountain installs in Big Bear and Wrightwood run real heating hours and fail on a different curve — more wear, fewer idle-related faults. Either way, fall maintenance in October is the cheapest insurance; the cold-air and ignition chains are in our furnace blowing cold air and furnace ignitor failure guides, and older standing-pilot units are covered in pilot light won’t stay lit.
Trane no-heat repair pricing
Flat-rate, parts and labor, from our SoCal service tickets. Diagnostic is $89 ($149 after-hours), credited to the repair if you proceed:
| Trane furnace repair | Typical cost |
|---|---|
| Diagnostic (waived with repair) | $89 / $149 after-hours |
| Hot-surface ignitor | $245–$485 |
| Flame sensor (clean or replace) | $185–$295 |
| Gas valve | $385–$685 |
| Blower motor | $480–$890 |
| Integrated control board | $480–$950 |
| Draft inducer motor (XV80 / XV95) | $580–$1,100 |
| Heat exchanger (crack — we quote replacement) | $1,500–$3,500 |
Warranty-covered parts on a registered Trane furnace still carry labor; we look up your registration before ordering. These are the same flat rates on our Trane furnace repair page.
Repair or replace your Trane furnace
Under 10 years old with a repair under roughly a third of replacement cost, repair it — an XV95 with a failed ignitor or inducer at year 9 has plenty of cabinet and heat-exchanger life left. Over 15 years, or any age with a cracked heat exchanger, replace it: a cracked exchanger is a carbon-monoxide path, and we red-tag and shut the gas before leaving. The 10-to-15-year window is judgment, and we give you the repair figure and a written replacement quote side by side. See furnace installation when replacement is the call.
American Standard furnaces
American Standard and Trane furnaces are the same equipment under different badges — same integrated control board, gas valve, ignitor, and inducer, cross-referencing to the same parts and the same no-heat diagnosis. We service both with the same meters and warranty channels. For the cooling side of a Trane system, see Trane AC repair, and the full lineup on our Trane brand page.