🚨 Troubleshooting Guide: What Mike Did When His System Stopped Cooling
🏠 Introduction: When a Perfectly Good AC Suddenly Fails
Saturday afternoon. 94°F outside. Humidity is pushing 70%. Mike had just come home from a grocery run, ready to relax in the chilled comfort of his home.
But instead of a cool breeze, he was greeted by a blast of warm, sticky air from his vents.
His Goodman 2-Ton 13.4 SEER2 R-32 Air Conditioner (Model GLXS3B2410) had been running like a champ for two summers.
No strange noises, no maintenance issues. Until now.
“I didn’t hear anything wrong,” Mike said. “The blower was running, but the air wasn’t cold. It was like the AC had given up.”
Rather than panic, Mike remembered his installer’s advice:
“When your AC stops cooling, it’s usually one of five things — airflow, power, refrigerant, thermostat, or dirt.”
This article follows exactly what Mike did — step by step — to bring his system back from lukewarm limbo to crisp, efficient cooling.
Along the way, you’ll learn why each step matters, what’s safe for DIY homeowners, and when to hand things over to a professional.
⚙️ 1️⃣ How an R-32 System Works (and Why It Needs Precision)
Before grabbing tools, Mike revisited the basics.
Understanding how his R-32 system moves heat helped him troubleshoot smarter.
🌬️ A. The Cooling Process in a Nutshell
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Compressor: Pressurises refrigerant vapor.
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Condenser Coil (Outdoor): Releases heat to outside air.
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Expansion Valve: Drops refrigerant pressure, cooling it rapidly.
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Evaporator Coil (Indoor): Absorbs heat from indoor air.
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Blower Fan: Circulates cooled air through ducts and returns warm air.
When every part works in harmony, the result is steady, quiet comfort.
But if even one step falters — dirt on the coil, a loose wire, or refrigerant loss — the whole system’s performance crashes.
⚡ B. Why R-32 Is Different
Mike Goodman uses R-32, a newer generation refrigerant replacing R-410A.
It’s more efficient and has 68 % lower Global Warming Potential (GWP 675), but it runs at higher pressures and requires airtight precision.
That’s why maintenance matters.
As Daikin’s R-32 Technical Overview explains:
“To maintain R-32’s efficiency, refrigerant charge and system cleanliness must remain within precise tolerances.”
So Mike knew: anything involving refrigerant charge or system pressure was for certified pros only (EPA Section 608 Requirements).
🔍 2️⃣ Step One — Confirm the Problem Before Guessing
Mike started by documenting what he saw and heard — because guessing leads to wrong fixes.
🧭 A. What He Observed
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Thermostat: set to 72 °F, “Cooling” mode active
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Indoor blower: running normally
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Outdoor fan: spinning
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Airflow: strong, but warm
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Copper lines: no frost, slightly cool
He grabbed his infrared thermometer:
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Return air = 77 °F
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Supply air = 74 °F
That’s only a 3 °F split, instead of the normal 14–20 °F cooling difference (Energy.gov – Common Air Conditioner Problems).
Something was preventing proper heat exchange — either airflow restriction or refrigerant flow issues.
🕵️ B. Listen for Clues
He also listened closely:
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No grinding or squealing.
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Compressor hummed briefly, then clicked off after two minutes — short cycling.
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The fan kept spinning even after the compressor shut off.
Those clues meant the outdoor fan circuit worked, but the compressor wasn’t staying on long enough to cool.
🧰 3️⃣ Step Two — Start with Power and Thermostat
Always rule out the easy fixes first.
🖲️ A. Thermostat Check
He verified:
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Mode = Cool
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Fan = Auto
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Setpoint < room temp
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Batteries = replaced
Weak thermostat batteries can drop the signal voltage below 24 V AC, confusing the control board.
⚡ B. Power Reset
Mike flipped both the air-handler breaker and condenser breaker OFF for 60 seconds, then ON.
He also checked the outdoor disconnect — a simple pull-out fuse block — to ensure it was seated.
Goodman recommends a 3–5 minute delay before restart to let internal compressor pressure equalise .
Still, no cold air.
Time for airflow.
🌬️ 4️⃣ Step Three — Airflow & Filter: The Hidden Culprit
When air doesn’t move freely, nothing else matters.
🧼 A. Filter Check
Mike pulled out his return filter — it was coated with grey dust.
He’d forgotten to replace it last month.
He swapped it for a clean MERV 8 pleated filter, making sure the airflow arrow pointed toward the air handler.
ENERGY STAR’s Air Filter FAQ notes:
“A dirty filter can increase energy use by up to 15 % and cause coil icing.”
After replacing the filter, airflow from vents improved immediately, though air temperature stayed warm.
🌪️ B. Ducts and Vents
Mike walked through every room:
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All supply vents open ✅
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No furniture blocking returns ✅
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Grilles vacuumed clean ✅
Uneven cooling often stems from blocked registers or pinched flex ducts, but his looked clear.
🌳 5️⃣ Step Four — Outdoor Unit Inspection
🌿 A. Check for Obstructions
Outside, he found grass clippings and mulch stuck to the Goodman condenser.
He turned off the power, then:
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Removed debris by hand.
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Brushed the coil gently with a soft paintbrush.
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Sprayed from inside out with a garden hose (low pressure).
After drying, he restored power — airflow was stronger, but still lukewarm air inside.
🧊 B. Compressor and Fan Behaviour
He stood over the unit:
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Fan speed steady.
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Compressor clicked on … then off after 2 minutes.
That pointed to either low refrigerant (pressure switch cutoff) or overheating from poor heat rejection.
The next suspect: indoor coil performance.
💧 6️⃣ Step Five — Inspect Indoor Air Handler & Coil
🌀 A. Blower Wheel
Breaker OFF, panel removed — the blower wheel was caked in dust.
He vacuumed and wiped blades with coil cleaner.
A dirty wheel cuts airflow ≈ 20 %, just enough to ice the coil.
❄️ B. Evaporator Coil Check
With a flashlight, Mike saw thin frost across the upper coil edge — a classic airflow restriction symptom.
He turned off the system and let it thaw for two hours.
Then he sprayed no-rinse coil foam. The condensate would rinse residue away naturally.
💦 C. Condensate Drain Flush
While there, he noticed water pooling under the PVC trap — clog alert.
He poured 1 cup of vinegar + 1 cup warm water, waited 20 min, then flushed with clean water.
Finally, he vacuumed the outside drain outlet using his shop vac.
System back on … still warm air. Time to check electricals.
🔋 7️⃣ Step Six — Electrical Connections and Capacitor
⚡ A. Tighten Connections
He killed power at the disconnect, removed the service panel, and inspected terminals.
One spade connector on the dual run capacitor was loose. He crimped it snug and added dielectric grease.
Loose connections cause voltage drop → relay chatter → compressor short-cycling.
🔩 B. Capacitor Testing
Capacitor label = 45/5 µF ± 6 %.
His multimeter readings = 44.7 and 4.9 — perfect.
Anything > 10 % off needs replacement (Test an AC Capacitor).
Capacitor fine ✅
Wiring secure ✅
Still no cool ❌
That left one possibility — refrigerant flow.
🧊 8️⃣ Step Seven — Refrigerant Clues (Without Handling It)
🧭 A. Line Temperatures
He felt both copper lines:
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Large suction line: cool but not cold, no sweat forming.
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Small liquid line: warm, not hot.
That pattern = low mass flow of refrigerant — either undercharge or restriction.
🔁 B. Compressor Cycling
Compressor ran ≈ 2 min, off 3 min — short cycling.
Most likely: low charge triggering pressure switch cutoff.
Mike stopped there.
Anything beyond this point requires licensed refrigerant work.
He called a pro and shared his findings — saving diagnostic time and labour fees.
🧑🔧 9️⃣ Step Eight — Professional Diagnosis & Repair
🧪 A. Tech Findings
The Goodman-authorised technician arrived with R-32-rated gauges:
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Confirmed low charge.
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Detected UV-dye leak at flare connection near condenser service valve.
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Repaired flare nut and O-ring.
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Pressure-tested with nitrogen (450 psi).
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Pulled vacuum to 500 microns.
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Recharged precisely per manufacturer's weight.
⚙️ B. Results
| Parameter | Before | After |
|---|---|---|
| Suction Pressure | 85 psi | 125 psi |
| Discharge Pressure | 185 psi | 320 psi |
| Temp Split ΔT | 3 °F | 18 °F |
| Compressor Amps | 7.1 A | 5.6 A |
System performance restored — cool, quiet, balanced.
Repair bill: $280, including recharge and leak fix.
🧮 🔟 Mike’s Preventive Plan
| Interval | Task | Why It Matters |
|---|---|---|
| Monthly | Replace filter; flush drain | Maintains airflow & prevents overflow |
| Quarterly | Rinse condenser coil; vacuum blower | Preserves efficiency |
| Semi-Annual | Check wiring & capacitor | Stops failures early |
| Annual | Professional inspection & pressure test | Keeps warranty valid |
| As Needed | Monitor thermostat calibration | Ensures accurate cycling |
Printable checklists available via The Furnace Outlet’s R-32 Maintenance Guide.
⚠️ 11️⃣ Common “No-Cool” Scenarios and Fixes
| Symptom | Likely Cause | DIY Action | Call a Pro When… |
|---|---|---|---|
| Air flows but warm | Dirty filter/coil | Replace filter, clean coils | Still warm after 1 hr |
| Ice on the copper line | Low airflow | Thaw coil, change filter | Ice returns |
| Short cycling | Low charge / faulty switch | Observe timings | Persisting cycles |
| No outdoor fan | Failed capacitor | Check connections | Fan motor hot/dead |
| Water under the unit | Clogged drain | Flush with vinegar | Repeats often |
| Uneven temps | Blocked vents / leaky ducts | Open vents | Duct test needed |
🧠 12️⃣ Mike’s Lessons Learned
“I realised the system wasn’t broken — it was suffocating.”
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Start with airflow.
80 % of problems come from blocked filters or dirty coils. -
Listen and observe before touching anything.
The system tells you what’s wrong. -
Respect R-32.
Higher pressure and A2L rating mean leave refrigerant to pros. -
Maintenance is cheaper than repairs.
A $10 filter change prevented a $300 service call. -
Document everything.
He logs service dates to protect his 10-year Goodman Warranty (Warranty Registration).
🔧 13️⃣ Recommended Homeowner Tool Kit
| Tool | Purpose | Cost (USD) |
|---|---|---|
| IR Thermometer | Measure supply/return temps | 25 |
| Wet/Dry Vac | Drain cleaning | 40 |
| Fin Comb | Straighten coil fins | 8 |
| Multimeter | Voltage checks | 30 |
| Non-acid Coil Cleaner | Safe coil cleaning | 10 |
| Gloves & Goggles | Protection | 12 |
Safety first: turn off power before opening panels. Never cut or open refrigerant lines.
🌍 14️⃣ Environmental Impact of Prompt Repairs
Each pound of R-32 leaked = ~675 lb CO₂ equivalent.
Mike’s tiny flare leak (1.3 lb) would have emitted the same amount as driving 1,400 miles.
By fixing early, he prevented that impact (EPA GreenChill Program).
Quick repairs protect both planet and pocket.
📅 15️⃣ Seasonal Maintenance Calendar
| Season | Key Tasks | Benefit |
|---|---|---|
| Spring | Deep coil clean, filter change | Prep for summer load |
| Summer | Flush drain, inspect fan | Prevent breakdowns |
| Fall | Seal ducts, check insulation | Save winter energy |
| Winter | Cover top of condenser loosely | Keep debris out |
