Stop first if any of these apply
You smell gas. Leave your home right away without switching anything on or off. Once you are outside, call your gas company or 911.
Your carbon monoxide alarm sounds. Get everyone, including pets, outside into fresh air, and call 911.
You smell burning, see smoke or sparks, or a breaker trips again after you reset it. Turn the system off and call us. Do not keep resetting a breaker that trips.
Check 1: The thermostat
- Is it set to Cool, Heat or Auto, not Off?
- For cooling, is the set temperature below the room temperature? For heating, above it?
- Is the screen blank? Many thermostats run on batteries; try fresh ones.
- Is a schedule or "hold" setting overriding what you just set?
- The fan setting: Auto runs the fan only while heating or cooling; On runs it continuously, which can feel like cool air in winter or warm air in summer.
Check 2: The power
- In your electrical panel, check the breakers for both the indoor unit (furnace or air handler) and the outdoor unit. Reset a tripped breaker once only.
- Outside, check the disconnect switch in the box mounted near the outdoor unit.
- Near the furnace or air handler, look for a service switch that looks like an ordinary light switch. It is easy to switch off by mistake.
- Make sure the furnace's front panel is firmly closed. Many furnaces have a safety switch that stops them from running when the panel is loose.
Check 3: The airflow
- Check the filter. A badly clogged filter can stop a system from heating or cooling properly, and in summer can even make the indoor coil freeze.
- Make sure supply vents and return grilles are open and not blocked by furniture or rugs.
Common symptoms and what they usually mean
| What you notice | What to do |
|---|---|
| Ice on the copper lines or outdoor unit | Switch cooling off and set the fan to On to thaw it, then call us. Often a filter, airflow or refrigerant problem. |
| Water around the indoor unit, or the system shut itself off | The condensate drain may be blocked and the safety switch has tripped. Call us. |
| Outdoor unit hums but the fan does not spin | Turn the system off to protect the compressor, then call us. |
| Air blows but is not cold or not warm | Run through the three checks above; if nothing changes, call us. |
| New rattling, grinding or squealing | Turn it off and call us before the noise becomes damage. |
When you call us
It helps to tell us what you are noticing, when it started, any sounds or smells, and whether you have already tried the checks above. If you can, have the brand and model of your equipment ready; it is on a label on the indoor and outdoor units.
For urgent service day or night, call 1-800-329-2568.
And beyond the quick checks: your system should be inspected by a trained technician at least once a year, ideally before the season it works hardest.