A well-functioning air conditioner is essential for home comfort in Sarasota’s hot, humid climate. Any change in air conditioner performance is worrisome, but before calling a cooling expert, check the thermostat. Minor thermostat problems can mimic more serious issues with the HVAC system and directly impact cooling system performance and comfort.
When thermostat problems develop, they are rarely dramatic events with sparks flying, or where smoke alarms sound. Most thermostat malfunctions cause subtle or sudden changes in the performance of your cooling system. Since the system’s functionality is affected, it is easy to misinterpret the symptoms as urgent HVAC equipment troubles when a simple fix at the thermostat may be all that is needed.
A faulty thermostat may be to blame if the air conditioner short cycles and runs almost nonstop, the living space seems warmer than your desired temperature setting, or you suddenly experience a cooling system failure. Learning how to troubleshoot these issues can help you avoid an unnecessary and costly service call.
The Air Conditioner Suddenly Stops Working
Check whether the thermostat’s display is lit. If it is not, the thermostat cannot signal the air conditioner to cycle on. Look for and address simple reasons why the thermostat isn’t getting power, such as dead batteries or a tripped breaker or blown fuse in your main electrical service panel.
If you’re certain it’s receiving power, shut off the thermostat breaker in order to safely take off the cover and examine the inner components. First, check for a buildup of dirt, soot, cigarette smoke or dust. A coating of debris on the mechanical and electrical components can affect a thermostat’s normal operation, so clean them carefully with canned compressed air or a soft brush.
Once it’s clean, check for obvious problems with the components, like loose wiring or terminal screws that need to be tightened. If you see signs of corrosion on the wiring, you can use the wiring schematic in your owner’s manual as a replacement guide, or simply replace the thermostat.
Room Temperature Never Reaches the Thermostat Setting
A buildup of grime can cause inconsistencies between the temperature setting and the actual room temperature, so follow the above cleaning instructions before taking any additional steps.
A poor installation job or good bump can leave a usually level thermostat off kilter. This can also cause temperature discrepancies. If this is the case, it’s easily corrected by placing a carpenter’s level above or below the thermostat and adjusting it so it’s sitting level.
A stuck heat anticipator is another possible culprit if the thermostat is a mechanical model. With the cover off, locate the anticipator by looking for a little metal arm sitting on a circular dial. Push the arm gently in either direction and it should become free.
If the thermostat is in a bad location , it will not be able to accurately regulate the temperature, so consider its position in your home. Is it exposed to direct sunlight, other heat sources or cold drafts? Is it located in an isolated spot that’s away from the living areas? If so, relocating it may help.
Frequent Short Cycling or Continuous Running
A thermostat that doesn’t sit level or is dirty inside can trigger the short cycling and almost continuous operation that erodes energy efficiency. Follow the above instructions to check for and resolve these two issues first.
Another possible cause is a poorly calibrated anticipator. You can try to lengthen the cooling cycle by moving the anticipator arm in single-notch increments toward the marking for “longer” on the round dial. Let the A/C complete a full cycle in between adjustments until you see an improvement.
If you’re not able to get the problem resolved with the above troubleshooting tips, have an experienced HVAC professional investigate further to identify the cause. Even if you are successful, it may be wise to upgrade from an older thermostat to a new programmable model, to avert future problems.
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