HVAC Repair for Heating and Cooling Systems

A home HVAC system is several pieces of equipment sharing one set of controls and ducts, so the first step is narrowing the symptom to the right part:

Warm air in cooling mode, an outdoor unit that won't start, or ice on the refrigerant lines point to the cooling side; see AC repair. A gas furnace that won't light, lights and shuts off, or locks out points to the burner and ignition side; see furnace repair. A heat pump does both jobs with one outdoor unit, so problems in either season start at heat pump repair. Rooms that are too hot or cold while others are fine usually trace to airflow and ducts; see air duct services.

If you can't tell whether the problem is the air conditioner, the furnace or the ducts, start with what is and isn't working.

Some parts work in every season, so one failure can stop both heating and cooling. The thermostat and its low-voltage wiring tell the equipment when to run. The blower in the furnace or air handler moves air across both the heat exchanger and the cooling coil, and a failed blower motor or capacitor stops airflow entirely. A clogged filter or blocked return restricts that airflow. Air conditioners and high-efficiency furnaces both produce condensate, and a clogged drain can trip a float switch that cuts power to the system. Tripped breakers and service switches are the simplest causes and the first things to check.

A diagnosis works from the controls toward the equipment: confirm the thermostat is calling for heat or cooling and that the control signal reaches the equipment, check power and safety switches, measure airflow and the temperature change across the system, then test the equipment in question. For air conditioners and heat pumps that means refrigerant pressures and electrical parts; for gas furnaces, the ignition sequence, flame sensing and venting. Finding the failed part before replacing anything keeps the repair to what the system actually needs.

A few minutes of checking can rule out the simple causes. For cooling-specific checks see the AC not cooling guide.

A single failed part on equipment in good condition is usually worth repairing. Replacement deserves a comparison when a major component fails on an older system, such as an air conditioner's compressor or a furnace's heat exchanger, when repairs keep recurring, or when the system uses phased-out R-22 refrigerant. Indoor and outdoor equipment are rated as matched pairs, so replacing one half of a split system can affect the other. See AC replacement, furnace installation and heat pump installation.

We are open 24 hours a day, 7 days a week, and same-day service is available. For emergency calls in Orange County, a technician typically arrives in 60 to 120 minutes, depending on technician availability, your location, traffic and call volume. That window is typical, not guaranteed, and we confirm your arrival time when you call. See emergency HVAC service for what to do while you wait.

If you smell gas or a carbon monoxide alarm sounds, leave the house and call your gas utility or 911 from outside before anything else. Turn the system off at the thermostat if you smell burning, and leave the house and call 911 if you see smoke or flames. If a breaker keeps tripping, leave it off rather than resetting it again, and don't open equipment panels: furnaces and outdoor units contain high voltage, and capacitors can hold a charge after the power is off.