# A Tempe Pre-Summer Tune-Up Caught a Capacitor That Would Have Failed on the First 115-Degree Day | Comfort Pros Blog > Capacitor was reading 58 percent of rated microfarad. The homeowner had no AC complaints, the system was cooling fine, and the part was a $20 component. We replaced it in 30 minutes and saved a July emergency call. URL: https://www.comfortprosaz.com/blog/tempe-pre-summer-ac-tune-up-caught-bad-capacitor/ Last-Modified: 2026-08-22 Author: Dyango P. Seasonal # A Tempe Pre-Summer Tune-Up Caught a Capacitor That Would Have Failed on the First 115-Degree Day Capacitor was reading 58 percent of rated microfarad. The homeowner had no AC complaints, the system was cooling fine, and the part was a $20 component. We replaced it in 30 minutes and saved a July emergency call. Dyango P. · August 22, 2026 · 4 min read ![Multimeter display showing a capacitor reading well below rated microfarad, the kind of failed component a spring service catches before a summer emergency](/images/misc/multimeter-display-showing-a-capacitor-reading-wel.webp) Marisol P. had been on the tune-up plan for three years. The visit in late April was the third one. Nothing was wrong. The system was cooling fine, the thermostat was holding setpoint, the electric bill was normal for April. We ran the spring tune-up anyway because that is what the plan covers, and that is when we caught the capacitor. The meter read **58 percent of rated microfarad**. The capacitor was functional but well below the threshold where we replace on sight. A $20 component. Thirty minutes of labor. We replaced it during the visit, which is exactly the kind of repair a spring tune-up is designed to catch. ## What a Bad Capacitor Does on a 115-Degree Day The capacitor on the condenser fan or compressor provides the torque the motor needs to start. As a capacitor ages, its actual microfarad rating drifts downward from the rated value. The motor still runs, but it is working harder to start and to keep running. The unit may cool adequately in spring weather. Under the load of a 115-degree day, the motor does not have the torque to keep going, the overload trips, and the unit shuts down. The homeowner hears a click from outside, the fan stops, the house starts heating up. On a 115-degree day that becomes an emergency call within two hours. On a 117-degree day it becomes an emergency call within thirty minutes. A capacitor that is reading 58 percent will fail under extreme heat. Not might. Will. The only question is whether it fails on the first 115-degree day, the third, or the fifth. Either way it is going to fail before the end of summer. ## Why We Caught It Early Three reasons, all of which are about being on the tune-up plan rather than about luck. **The capacitor was tested.** A spring tune-up includes checking the capacitors with a multimeter, not just visually inspecting them. A capacitor that looks fine on visual inspection can be at 60 percent of rated microfarad. The meter tells us what the eye cannot. **The threshold for replacement is conservative.** We replace at 80 percent of rated microfarad during a tune-up, which is well above the threshold where the component is visibly failing. The homeowner gets a part that is on its way out, replaced on a day when they have an appointment and can plan for the visit. **The visit was scheduled before the emergency.** A no-AC emergency call on a 117-degree day is the worst time to discover a failing capacitor. Same-day tickets are prioritized by household risk, the timing is not always what the homeowner wants, and the technician may have to dig through the truck for the right value. A spring tune-up is on the calendar. The capacitor gets caught, the homeowner gets a text when the tech is en route, and the visit is on the homeowner’s schedule rather than the weather’s. ## What the Visit Covered For reference, the spring tune-up on Marisol’s system ran about 75 minutes and included the following. **Thermostat check.** Confirm the thermostat is reading correctly and the setpoint is holding. Recalibrate if needed. Check the batteries if it is a battery-powered thermostat. **Indoor coil and blower.** Pull the blower if access allows, clean the blower wheel, check the motor amp draw against the rated FLA. A blower motor that is drawing high amps is a blower that is about to fail. Replace belts if it is a belt-drive system. **Condenser coil cleaning.** The condenser coil on the outside unit gets a chemical wash and a rinse. A condenser that is half-caked with dust and debris cannot reject heat at its rated rate. Cleaning the coil is the single biggest performance improvement available from a tune-up. **Refrigerant level check.** Measure superheat and subcooling. A system that is slightly low on charge gets topped off. A system that is significantly low gets a leak search before any refrigerant goes in - adding refrigerant to a leaking system is a 30-day fix, not a repair. **Capacitor check.** Both the start and run capacitors on the condenser fan and the compressor. Replace if any of them are below 80 percent of rated microfarad. **Contactor inspection.** Look for pitted or welded contacts. Replace on sight if the contacts are showing wear. **Electrical check.** Tighten electrical connections, check for voltage drop across the contactor, confirm the unit is properly grounded. **Drain line clear.** The condensate drain line from the indoor coil to the outside gets cleared. A clogged drain line means water backs up into the secondary pan or onto the ceiling, neither of which is what the homeowner wants to discover in July. ## What a Bad Tune-Up Looks Like We tell homeowners what to expect from a spring tune-up because not every company runs them the same way. A tune-up that took 25 minutes and did not include capacitor testing, refrigerant measurement, or contactor inspection was not a tune-up. It was a filter change and a coil rinse. A real tune-up is 60 to 90 minutes of work. The technician should be measuring things with a multimeter and a thermometer, not just spraying things with a hose. If the invoice for the tune-up does not line up with the work being done, the homeowner is being undersold. ## The Number | Item | What it covered | | --- | --- | | Spring tune-up | 75-minute visit, full checklist | | Capacitor replacement | $20 part, 30 minutes of labor | | Total | $178 flat-rate for the visit plus the part | That is the cost of catching one failing capacitor before it becomes a no-AC emergency on a 115-degree afternoon. The cost of the emergency visit - same diagnostic, same part, plus a same-day ticket premium - would have been two to three times higher. The cost of the visit on a 117-degree day with an infant in the household, on the other hand, is not a number we want to put on paper. ## What the Tune-Up Plan Actually Saves We track the failure rates of plan customers against non-plan customers every summer. The plan customers fail at about 25 percent the rate of non-plan customers on no-AC emergencies. The plan customers who do fail get caught earlier because the components were tested in spring rather than discovered in failure in summer. The plan customers pay about 40 percent less per summer in HVAC service costs because the failures that do happen are caught at scheduled-visit pricing rather than emergency-visit pricing. The plan pays for itself on the first avoided emergency visit. After that, every visit that catches something small before it becomes something big is money the homeowner did not have to spend on a no-AC day. ## What We Tell Homeowners Who Are Not on a Plan Schedule the tune-up for April or early May. The dispatch board fills up by mid-May with pre-summer prep calls, and the closer we get to the first 110-degree day the harder it is to fit everyone in. The visit takes about 90 minutes, costs in the neighborhood of $160 to $200 depending on the system, and it covers the list above. If the technician finds something that needs replacement, we tell you what it is, what it costs, and whether it can wait until fall or needs to be done before the summer load hits. **If your AC has not had a spring tune-up yet this year** - request a spring tune-up [/ac-maintenance/ →](/ac-maintenance/) or read more about what a proper spring tune-up covers [/guide/spring-ac-tune-up-checklist/ →](/guide/spring-ac-tune-up-checklist/) . ![Dyango P.](/images/squares/author-dyango-p.webp) Dyango P. [/about/#dyango-p →](/about/#dyango-p) Lead HVAC Service Technician - California Lead HVAC service technician covering the Crescenta Valley, San Gabriel Valley and the high desert. ✓ NATE Certified #hvac #tempe #tune-up #capacitor #seasonal #preventive-maintenance ## More From the Trucks ![Interior of a 1962 California bungalow with original plaster walls, representing a Burbank home where three pinhole leaks in eighteen months led to a whole-home PEX-A repipe](/images/misc/interior-of-a-pre-1960-california-bungalow-with-a-.webp) Case Study Sep 12, 2026 ### A 1962 Burbank Bungalow, On Its Third Pinhole in Eighteen Months - The Whole-Home Repipe We Did in PEX-A Three pinhole leaks in galvanized and soft copper in eighteen months. The fourth one was already forming. We repiped the whole house in PEX-A in four days, with the drywall patched back better than it was. Read the story [A 1962 Burbank Bungalow, On Its Third Pinhole in Eighteen Months - The Whole-Home Repipe We Did in PEX-A →](/blog/burbank-whole-home-repipe-pex-a-1960s-copper/) ![A wall-mounted ductless mini-split head installed high on a stucco wall above a garage workbench, with a slim white line-set cover running down to the outdoor unit](/images/featured/wall-mounted-mini-split-head-above-a-garage-workbe.webp) Case Study Sep 10, 2026 ### Adding AC to a La Crescenta Casita - A Ductless Mini-Split in One Day A converted garage casita in the Crescenta Valley foothills had no AC, no ductwork, and a tight electrical panel. A single-zone ductless mini-split solved all three - installed in one day, no drywall opened. Read the story [Adding AC to a La Crescenta Casita - A Ductless Mini-Split in One Day →](/blog/la-crescenta-ductless-mini-split-casita/) ![A restored Pasadena driveway and front yard after a trenchless sewer liner was installed, showing that no excavation was needed for the sewer repair](/images/hero/restored-driveway-and-landscaping-after-a-trenchle.webp) Case Study Sep 10, 2026 ### Pasadena Sewer Lateral: We Lined 48 Feet of Pipe Under a 50-Year-Old Driveway Without Digging A 1968 clay sewer lateral with root intrusion at every joint. The homeowner was told she needed a $22,000 excavation. Cured-in-place lining sealed every joint from the inside and saved the driveway. Read the story [Pasadena Sewer Lateral: We Lined 48 Feet of Pipe Under a 50-Year-Old Driveway Without Digging →](/blog/pasadena-sewer-lateral-cured-in-place-lining/) ![Comfort Pros HVAC technician greeting a homeowner at the front door](/images/hero/candid-wide-photo-of-a-technician-shaking-hands-wi.webp) Same-day appointments available ## Ready for an Honest Number? Run a real load calculation online, or call the team in your state. Flat-rate pricing either way, and nobody shows up to sell you something bigger than you need. 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)