Repair service
HVAC Guides
Browse published HVAC guidance by system, equipment, or component, then choose the article that matches your problem.
Browse by system or equipment
Start with the HVAC system you are working on.
- Air Conditioners Cooling-system guidance for airflow, temperature, drainage, controls, and outdoor-unit problems. 155 guides
- Furnaces Guides for furnace heating, ignition, airflow, cycling, and control problems. 85 guides
- Boilers Boiler guidance covering heat, pressure, circulation, leaks, and controls. 68 guides
- Heat Pumps Troubleshooting for heat-pump heating, cooling, defrost, and airflow concerns. 28 guides
- Mini Splits Ductless mini-split guidance for cooling, heating, drainage, and indoor-unit issues. 31 guides
- Air Handlers Air-handler guidance for airflow, controls, filters, coils, and blower operation. 17 guides
- Thermostats Thermostat guidance for blank screens, wiring, settings, and system communication. 35 guides
- Condensers Outdoor condenser guidance for fan, coil, capacitor, and compressor symptoms. 22 guides
Browse by component
Use a component category when you already know which part of the system is involved.
- Blower Motors Guidance for blower starting, speed, noise, airflow, wheels, and related controls. 53 guides
- Compressors Compressor-related guidance for starting, noise, temperature, and cooling symptoms. 27 guides
- Capacitors Capacitor guidance focused on symptoms, safe limits, and professional testing decisions. 23 guides
- Evaporator Coils Evaporator-coil guidance for icing, airflow, drainage, and cooling symptoms. 17 guides
- Condensate Drains Guidance for condensate drainage, overflow, clogs, pans, and water around HVAC equipment. 11 guides
- Filters Filter guidance for airflow, fit, replacement intervals, and system symptoms. 26 guides
- Contactors Contactor-related guidance for starting, control signals, and safe service boundaries. 11 guides
Other published guides
These guides do not yet belong to one of the established categories above.
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AC Outdoor Fan Runs but the Compressor Is Silent and Air Is Warm
An outdoor fan that runs while the compressor is silent and the house receives warm air is a symptom, not proof of one failed part. From a safe distance, confirm the thermostat is calling for cooling, note whether the outdoor fan is actually running, and listen for silence, a click, or a hum; also check only the accessible indoor filter and visible exterior for damage, odor, oil, or ice.
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Carrier Air Conditioner Not Cooling After 30 Minutes: Capacitor-Safe Checks
If a Carrier air conditioner is still not cooling after 30 minutes and a capacitor is suspected, do not assume the capacitor is the cause or open the outdoor unit. A weak capacitor can leave a compressor or fan humming, cycling, or unable to reach normal operation, but the same symptom can come from the thermostat, filter, airflow, breaker, outdoor fan, compressor, ice, or refrigerant.
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Heat Pump Defrost Mode: Steam Vapor, Reversing Valve, and Outdoor Fan Cycle
A brief cloud of steam from a heat pump's outdoor unit can be normal defrost vapor: the system temporarily reverses refrigerant flow to warm the outdoor coil and melt frost. During that interval, the outdoor fan may stop, a swishing sound may occur, and AUX heat may appear on the thermostat; these details vary by system.
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Thermostat Screen Blank: Furnace Blower Door Switch and Float Switch Trip
A blank thermostat usually means the thermostat has lost its low-voltage power, but the cause can be upstream of the wall display. Check only the user-accessible basics first: replace batteries if the thermostat uses them, confirm the HVAC breaker and furnace service switch are on, and make sure the furnace blower/access door is fully seated.