# Furnace Repair Gilbert AZ | Comfort Pros AZ and CA > Furnace and heating repair in Gilbert and Greater Phoenix. Ignitor, flame sensor and heat exchanger diagnostics with carbon monoxide testing. Flat-rate pricing. URL: https://www.comfortprosaz.com/furnace-repair/ ![Technician servicing an open gas furnace cabinet in a residential garage](/images/misc/candid-photo-of-a-technician-working-inside-an-ope.webp) CO Testing Included Same-Day Service # Same-Day Furnace Repair With a Carbon Monoxide Safety Check Included Last updated: August 25, 2026 Same-day heating repair with carbon monoxide safety testing on every gas furnace call. Licensed AZ & CA Flat-rate pricing 17 years in business Get Your TrueQuote [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) (480) 435-2334 [tel:+14804352334 →](tel:+14804352334) From $ 89 diagnostic from $89, flat-rate repair quoted before work begins 4.9 Rating 115+ Google reviews Same-Day Service Across AZ and CA service areas Licensed & Insured AZ ROC 364742 | CA C-20 #1040927 Flat-Rate Pricing Quoted before work begins Sound familiar? ## What Brings People to Us for Furnace Repair The situations behind most of these calls, and what we actually do about each one. ### The furnace fails on the first genuinely cold night It sat unused for eight months, then everyone in the valley turns their heat on within the same 48 hours. Dust on a flame sensor and a tired ignitor pick that exact evening to give out. Same-day heating dispatch with ignitors, flame sensors, limit switches and control boards already on the truck, so most calls end with the heat back on. ### Nobody checks for carbon monoxide A cracked heat exchanger can vent combustion gases into the return air without a single obvious symptom. Most repair visits never put a combustion analyzer near the flue. Every gas furnace visit includes combustion analysis and carbon monoxide testing at no extra charge, with the readings written on the service tag. ### Air blowing, but it is cold The blower runs and nothing warms up. It could be the ignition sequence, a tripped limit, a heat pump stuck in defrost, or a thermostat calling for the wrong stage. We watch the ignition sequence end to end rather than guessing from the symptom, and we troubleshoot heat pump auxiliary heat and defrost as part of the same call. ### Being told to replace it without seeing why Heat exchanger concerns get raised often and documented rarely. A replacement quote arrives with no photograph, no reading and no explanation. You hear the specific component and the specific measurement. When a furnace genuinely is unsafe to run we will tell you plainly, and we check warranty by serial number before quoting anything large. ## Why Desert Furnaces Fail on the First Cold Night Heating equipment in our service area runs a handful of weeks a year. Homeowners reasonably assume that means it barely wears out. In practice it means something different: the system sits idle for ten months and is then asked to run hard, and a lot of components do not survive that transition gracefully. That is why heating failures here cluster. The first genuinely cold night produces a week’s worth of no-heat calls in a single evening, and every technician in the valley gets booked at the same time. A fall heating check in October costs less than a December emergency and takes you out of that queue entirely. The Antelope Valley is the exception. Palmdale and the high desert see genuine freeze cycles and real heating demand, which is the one part of our coverage where a dual-fuel hybrid system [/guide/dual-fuel-hybrid-systems/ →](/guide/dual-fuel-hybrid-systems/) makes clear economic sense. ## How We Diagnose a Heating Fault A gas furnace ignition sequence has a fixed order, and a failure almost always announces itself at a specific step. So we watch the whole sequence rather than swapping parts by likelihood: 1. **Call for heat.** Thermostat closes the circuit. 2. **Inducer draft motor.** Starts and establishes draft. 3. **Pressure switch.** Proves the draft. A stuck or blocked switch stops the sequence here. 4. **Hot surface ignitor.** Glows. A cracked or open ignitor stops it here. 5. **Gas control valve.** Opens, burners light. 6. **Flame sensor.** Confirms flame within a few seconds. A sooted sensor fails to confirm, the valve closes, and you get cold air from a running blower. This is the single most common fault we find. 7. **Blower.** Engages after the heat exchanger warms. 8. **Limit switch.** Watches for over-temperature. A tripping limit switch usually means restricted airflow rather than a bad switch. Then, on every gas appliance, combustion analysis and a carbon monoxide reading, plus a heat exchanger inspection. ## Types of Heating Repair We Handle **Ignition faults.** Hot surface ignitors, flame sensors, spark igniters and control boards. The most common category and usually the cheapest. **Combustion air faults.** Inducer draft motors, pressure switches, blocked flues and condensate blockages in condensing furnaces. **Gas train faults.** Gas control valves, manifold pressure problems and multi-stage burner faults. **Safety faults.** Limit switches, rollout switches and heat exchanger failures. This is the category where we occasionally recommend shutting an appliance down rather than repairing it. **Heat pump heating faults.** Reversing valves and their solenoids, defrost boards and sensors, electric heat strip sequencers, and balance point settings that leave a system running on expensive auxiliary heat when the heat pump should be handling the load. **Airflow faults.** Blower motors, capacitors and duct restrictions, all of which show up as heating symptoms even when the burner side is perfect. ## Cost Guide | Repair category | Typical range | Notes | | --- | --- | --- | | Flame sensor clean or replace | $190 - $280 | Most common single fault we find | | Hot surface ignitor | $240 - $380 | Carried on the truck | | Pressure switch or limit switch | $260 - $420 | Often signals an airflow problem worth checking | | Inducer draft motor | $520 - $780 | Warranty status matters here | | Gas control valve | $580 - $950 | Combustion re-verified afterward | | Heat pump reversing valve solenoid | $340 - $620 | Full valve replacement costs more | The diagnostic starts at $89 and is credited toward the repair. Nothing gets touched before you have the flat-rate number. ## When Repair Is Not the Right Answer We will tell you to replace rather than repair when: - The heat exchanger shows a crack or combustion analysis indicates a breach - The furnace is over twenty years old and needs a major component - Repeated short-cycling has caused cumulative thermal damage - Repair cost approaches a third of replacement cost on ageing equipment If that is where you land, furnace installation [/furnace-installation/ →](/furnace-installation/) here is a different conversation than in a cold climate, because a six-week heating season changes the payback math on efficiency tiers. Our guide on furnace repair vs replacement [/guide/furnace-repair-vs-replacement/ →](/guide/furnace-repair-vs-replacement/) walks through it. And if what you actually have is a safety concern rather than a comfort one, cracked heat exchanger and carbon monoxide [/guide/cracked-heat-exchanger-carbon-monoxide/ →](/guide/cracked-heat-exchanger-carbon-monoxide/) is worth reading before you run the system again. Transparent Pricing ## How Much Does Furnace Repair Cost? Every gas furnace visit includes carbon monoxide testing at no extra charge. That is not an upsell line, it is a safety step that should be standard. ### Diagnostic Full heating diagnostic with CO testing From $89 - Ignition sequence observed end to end - Combustion analysis and carbon monoxide testing - Heat exchanger inspection - Credited toward the repair if you proceed Get exact pricing [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) Most chosen ### Common repairs Ignitor, flame sensor, limit switch, thermostat $190 - $520 - Ignition components carried on the truck - Flat rate covering parts and labor - Combustion re-verified after the repair - Parts and labor warranty on completed work Get exact pricing [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) ### Major repairs Inducer motor, gas valve, control board $520 - $950 - Manufacturer warranty checked by serial number - Repair-versus-replace math shown honestly - Heat pump reversing valve and defrost work included - Financing available where the number is large Get exact pricing [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) ### Financing available GreenSky, Wisetack and Goodleap, so you can pick the lender that fits your credit profile. Where your equipment qualifies for a utility rebate, it stacks with financing. Compare options [/financing/ →](/financing/) Why Choose Us ## Why Choose Us for Furnace Repair? ### CO testing on every gas call A furnace that runs six weeks a year can still crack a heat exchanger with age and repeated short-cycling. Testing takes minutes and is included on every visit rather than sold separately. ### Ignition parts on the truck Hot surface ignitors, flame sensors, pressure switches and limit switches all ride with us. On the first genuinely cold night of the year, a part on order is a week without heat. ### We diagnose the sequence, not the symptom 'Blowing cold' has six plausible causes. Watching the ignition sequence end to end identifies which one, rather than replacing parts in hopeful order. ### Heat pump competent too Reversing valves, defrost boards, auxiliary heat strips and balance point settings. Heat pumps fail differently from gas furnaces and plenty of technicians only really know one. ### We say when it is not safe If a heat exchanger has failed, the honest answer is to shut it down rather than patch it. We will tell you that plainly, including when it costs us the repair. ### Flat-rate, quoted first One number covering parts and labor before work starts. No hourly meter running while a diagnosis unfolds. Step by Step ## How Our Furnace Repair Works 1 ### Describe the symptom Blowing cold, short-cycling, not igniting, or clicking without lighting. Each one points at a different part of the sequence. 2 ### Watch the full ignition sequence Call for heat, inducer, pressure switch, ignitor, gas valve, flame sensor, blower. The failure almost always announces itself at a specific step. 3 ### Combustion and CO test Combustion analysis and carbon monoxide readings on every gas appliance, plus a heat exchanger inspection. 4 ### Flat-rate repair One number covering parts and labor, quoted before we start. Most ignition repairs finish the same visit. ## Still deciding on Furnace Repair? Flat-rate pricing quoted before we start, parts and labor warranty on the finished work, and an honest answer if you do not need it yet. Get Your TrueQuote [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) (480) 435-2334 [tel:+14804352334 →](tel:+14804352334) Our Work ## Recent Furnace Repair Jobs Click any photo to enlarge. ## How Comfort Pros AZ and CA Compares | What matters | Typical provider | Comfort Pros | | --- | --- | --- | | Carbon monoxide testing | Offered as an add-on | Included on every gas furnace visit | | Diagnosis method | Part swapping by likelihood | Full ignition sequence observed | | Ignition parts availability | Ordered, return visit | Carried on every truck | | Heat exchanger inspection | Visual glance if at all | Inspected and combustion verified | | Pricing | Hourly plus parts | Flat rate quoted before work begins | | Heat pump capability | Gas-focused technicians | Reversing valve and defrost diagnostics in-house | Reviews ## What Customers Say About Our Furnace Repair **4.9** from 115+ Google reviews > First cold snap of the year and the furnace would light then shut off after thirty seconds. They found a sooted flame sensor in about ten minutes and cleaned it. Charged me for the visit and nothing else. R Rachel M. Gilbert, AZ > They did a CO test without me asking and explained why. Nobody had ever done that on a furnace visit before. P Priya N. Scottsdale, AZ > Our heat pump was blowing cold in December and two other companies just wanted to talk about replacing it. Comfort Pros found a failed reversing valve solenoid. L Linda & Steve G. Burbank, CA Got Questions? ## Furnace Repair FAQs ### Why is my furnace blowing cold air? The ignition sequence has several steps and a failure at any one of them produces the same symptom. The most common cause we find is a sooted flame sensor: the furnace lights, the sensor fails to confirm flame within a few seconds, and the gas valve closes as a safety measure, leaving the blower running cold air. Second is a failed hot surface ignitor, which produces a furnace that tries repeatedly and never lights. Third is a pressure switch or inducer motor fault, where the safety circuit never allows ignition to begin. Fourth is a tripped high limit switch, usually caused by restricted airflow from a dirty filter. Fifth, on a heat pump, is a reversing valve or defrost fault, where the system is genuinely running in cooling mode by mistake. The one thing you can safely check yourself is the filter. Everything else involves gas or a sealed combustion circuit and needs a technician. ### Do you really test for carbon monoxide on every visit? Yes, on every gas furnace call, and it is included rather than sold. The reasoning is specific to this market. Furnaces here run a handful of weeks a year, which people assume means low wear, but low use combined with age and repeated short-cycling is exactly the profile that produces heat exchanger cracks. A cracked heat exchanger can put combustion products including carbon monoxide into your supply air, and it is not visible without inspection. Combustion analysis and a CO reading take a few minutes. There is no good reason for them to be optional. ### How much does furnace repair cost? The diagnostic starts at $89 and is credited toward the repair. Common repairs run $190 to $520 and cover hot surface ignitors, flame sensors, pressure switches, limit switches and thermostats. Major repairs land between $520 and $950 for inducer draft motors, gas control valves and control boards. All of it is quoted flat-rate before work starts, covering parts and labor together. Where the number is large, we check the manufacturer warranty by serial number first, because a covered part changes the whole conversation. ### My furnace only runs six weeks a year. Does it still need service? Especially then. Equipment that sits idle for ten months does not always restart gracefully. Ignitors fail on their first cold-night cycle, flame sensors soot up, inducer bearings stiffen, and rodents nest in cabinets that have been undisturbed since March. A fall heating check catches those in October rather than on the first genuinely cold night when every technician in the valley is booked. ### What is a cracked heat exchanger and how serious is it? The heat exchanger is the metal barrier separating combustion gases from the air that circulates through your house. It expands and contracts with every heating cycle, and over years of that, particularly with the thermal stress of short-cycling caused by restricted airflow, metal fatigue can produce a crack. When that happens, combustion products including carbon monoxide can pass into the supply air. It is the one furnace failure that is genuinely a safety issue rather than a comfort issue. If we find one, the honest recommendation is to shut the appliance down and replace it rather than attempt a repair, and we will say so even though it means the repair we were called for does not happen. ### Do you work on heat pumps as well as gas furnaces? Yes, and they fail differently. Heat pump heating faults usually involve the reversing valve, the defrost board and sensor, the auxiliary heat strips, or a balance point set incorrectly so the system leans on expensive strip heat when it should not. A heat pump blowing cool air in winter is often a reversing valve problem rather than a refrigerant one, and diagnosing it requires knowing what to look for. Palmdale and the high desert see the most genuine heat pump heating demand in our service area. ### How fast can you get out? Same-day appointments are available across our Arizona and California service areas, and no-heat calls get priority when temperatures are genuinely low. The complication is that heating failures here cluster: the first cold night produces a week's worth of calls in one evening. Booking a fall heating check in October is the reliable way to avoid being in that queue. ### Why does my furnace turn on and off repeatedly? That is short-cycling, and it has two main causes. Restricted airflow, usually a dirty filter or a closed-off duct system, causes the high limit switch to trip on temperature and shut the burners down, then reset and repeat. Or the furnace is genuinely oversized for the house, so it reaches setpoint before completing a proper cycle. Short-cycling is not just inefficient, it is the thermal stress pattern most associated with heat exchanger failure, so it is worth diagnosing properly rather than living with. ### Is it worth repairing an old furnace? The calculus is age, safety and cost. A furnace under fifteen years old with a failed ignition component is a clear repair. A furnace over twenty years old needing a gas valve or an inducer motor is a closer call, and if the heat exchanger shows any sign of failure it is not a call at all, it is a replacement. In this market the added consideration is the short heating season: a high-efficiency condensing furnace that pays back quickly in a cold climate pays back slowly here, which affects what tier makes sense on replacement. ### What warranty comes with a heating repair? Completed repairs carry a parts and labor warranty, and manufacturer-supplied parts carry their own warranty in addition. Documented annual maintenance is what keeps most manufacturer warranties valid, which is one of the reasons the fall heating check is worth booking. ### Can I fix a flame sensor myself? We would rather you did not. Cleaning a flame sensor is mechanically simple, but doing it requires opening a gas appliance cabinet, and the failure is not always what it appears to be. A sensor that soots up repeatedly is telling you something about combustion quality, and the underlying cause is what actually needs addressing. If it turns out to be a five-minute clean, our invoice reflects that. ### Still have a question? Call the team in your state and talk to someone who actually works on these systems. (480) 435-2334 (AZ) [tel:+14804352334 →](tel:+14804352334) (818) 690-7951 (CA) [tel:+18186907951 →](tel:+18186907951) Guides ## Read Before You Decide Plain-language answers to the questions homeowners ask us about Furnace Repair. concern ### Cracked Heat Exchangers and Carbon Monoxide: What Desert Homeowners Should Know Soot, odd flame color, headaches, a CO detector alarm - the warning signs that matter, why lightly used desert furnaces still crack, and why this isn't a repair. Read guide [Cracked Heat Exchangers and Carbon Monoxide: What Desert Homeowners Should Know →](/guide/cracked-heat-exchanger-carbon-monoxide/) comparison ### Furnace Repair vs. Replacement in a Mild-Winter Climate Age and repair-cost thresholds adjusted for low annual heating hours, when pairing with an AC replacement saves labor, and which safety failures aren't optional. Read guide [Furnace Repair vs. Replacement in a Mild-Winter Climate →](/guide/furnace-repair-vs-replacement/) concern ### Why Is My Furnace Blowing Cold Air? Ignition failure, a fouled flame sensor, a tripped limit switch or just the fan setting - here's how to tell which, plus what repeated lockouts are warning you about. Read guide [Why Is My Furnace Blowing Cold Air? →](/guide/why-is-my-furnace-blowing-cold-air/) ## Related Services ### Furnace Installation & Replacement Gas furnace, heat pump and dual-fuel replacement sized for actual regional heating hours. View details [Furnace Installation & Replacement →](/furnace-installation/) ### AC Repair Fast, flat-rate air conditioning repair when your system quits in extreme heat. View details [AC Repair →](/ac-repair/) ### Indoor Air Quality Whole-home air purification, UV-C, media filtration and smart thermostat setup. View details [Indoor Air Quality →](/indoor-air-quality/) ![](/images/hero/warm-lit-living-room-on-a-cold-desert-evening-with.webp) Same-day appointments available ## Ready to Book Furnace Repair? Flat-rate pricing quoted before we start, and an honest answer about whether you actually need this service. Same-day appointments available across Arizona and California. Get Your TrueQuote [https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com) (480) 435-2334 [tel:+14804352334 →](tel:+14804352334) Flat-rate pricing, no upsells Parts and labor warranty Licensed in AZ and CA California team: (818) 690-7951 [tel:+18186907951 →](tel:+18186907951) · Text us: (818) 489-2826 [sms:+18184892826 →](sms:+18184892826)