🔧 HVAC Troubleshooting & Maintenance Encyclopedia

Diagnose, maintain, and optimize your heating and cooling systems—51 expert guides covering AC repair, furnace troubleshooting, heat pumps, ductwork, indoor air quality, and energy efficiency.

📚 All (51)❄️ AC & Cooling (10)🔥 Heating & Furnace (8)🔄 Heat Pumps (3)💨 Ductwork & Airflow (4)🌡️ Thermostats & Controls (3)🌬️ Indoor Air Quality (4)⚡ Energy Efficiency & Upgrades (6)🚨 Emergency & Safety (5)🔧 Maintenance & Seasonal (4)🏢 Commercial HVAC (4)

Showing 10 of 10 topics in AC & Cooling

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AC Running But Not Cooling: Diagnosis Dirty condenser coils, frozen evaporator, refrigerant leak, or failed compressor—how to triage each cause before calling a technician.
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AC Short Cycling: Causes & Fixes Oversized unit, clogged air filter, refrigerant low, or thermostat location error—short cycling destroys compressors. Diagnose the root cause before the compressor fails.
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Refrigerant Leak: Signs & EPA Regulations Hissing sounds, ice on coils, and declining cooling—R-410A phaseout and why topping off without fixing the leak is illegal and expensive waste.
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Frozen Evaporator Coil: Why It Happens Low refrigerant or low airflow (dirty filter, blocked returns)—ice on indoor unit means turn it OFF immediately. Running a frozen system floods the compressor with liquid refrigerant.
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AC Capacitor Failure: Symptoms & Replacement Humming but fan not spinning, or compressor won't start—the most common AC failure. Start vs run capacitors and why a $20 part causes a $300 service call.
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Compressor Failure: Repair vs Replace Decision Compressor replacement costs $1,500-$2,800—on a 10+ year old system, replacement is usually smarter. The $5,000 rule: repair cost × age > $5,000 = replace.
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AC Strange Noises: Diagnosis Guide Squealing (belt/blower motor), grinding (compressor bearings), buzzing (electrical/contactor), rattling (loose panel or debris). Sound ID before the tech arrives.
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Central AC vs Ductless Mini-Split Ductless efficiency (no duct losses = 30% energy saved), multi-zone capability, and installation cost comparison. Why mini-splits dominate in homes without existing ductwork.
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AC Replacement Cost: Complete Pricing Guide Central AC replacement: $4,000-$8,000 for 3-ton system. Factors: SEER2 rating, single vs two-stage vs variable speed, existing ductwork condition, and regional labor rates.
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R-22 Freon Phaseout: What It Means for Your AC R-22 refrigerant banned from production/import since 2020. If your pre-2010 AC needs refrigerant, you're paying $200+/lb for recycled stock. Time to replace with R-410A or R-32 system.