HVAC electrical problems If your AC unit is experiencing electrical problems, it can cause the system to run continuously, even after reaching the desired temperature. Faulty wiring or a malfunctioning thermostat system fan can be the culprits.
This is the answer - there is an ``allow overcool'' setting that will continue to run your A/C to help with humidity. It needs to be turned off if you don't want this to happen.
It could be the wrong thermostat setting is being used, a clogged air filter or your thermostat itself is no longer working properly. When you have a heating system not shutting off, this issue makes it difficult to maintain the desired temperature inside the home.
The ``usual'' suspect is the solid state anticipation circuit not functioning properly, and in most cases requires replacing the thermostat. If it is a digital thermostat, blowing compressed air (easy now) into the thermostat, (if dust has accumulated around the temperature sensing thermistor), may solve your problem.
It could (likely) be one of two things. Either the thermostat is sticking and not disengaging or you have a short in the wiring.
With all that being said, if there are no extreme factors involved, the average run time for a furnace is 10-15 minutes per cycle. Your furnace may need to run two to three times an hour to maintain your desired temperature if your home has average insulation.
Dirty or Clogged Air Filter
If your heat pump continues to run after reaching the set temp, the first place to look is the filter cabinet. Is your air filter dirty and completely clogged with contaminants pulled from the air? If so, this dirty filter is likely causing your heat pump to run continuously.
If the thermostat keeps turning on and off, try replacing the batteries first. Faulty wiring – Loose wires or bad connections can cause intermittent power loss to the thermostat. Compatibility – Newly installed or replacement thermostats that repeatedly reboot may not be compatible with the home's HVAC system.
Some of the most common thermostat issues include:
The thermostat is broken, not properly level, or dusty. The thermostat needs to be recalibrated. There is loose wiring causing a thermostat issue.
A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.
If your heater won't turn off, the first thing you do is check the thermostat. The thermostat controls how the heating system runs. It detects the indoor temperature and signals the furnace to start or stop. So, if the thermostat malfunctions, it can signal the unit to run continuously.
If you try to resolve the issue after checking for default programming, energy-saving programs, old batteries, and even if someone has been changing the temperature in your home it may be time to contact a professional. There may be an issue with old wires or software.
The problem might be a faulty timer, pump, thermostat, heat exchanger, or a motorised valve. It is also possible for a malfunctioning programmer to cause issues of non-stop heating. In some cases, a blown fuse, faulty wiring, or problem with the circuit may be responsible for the problem.
Check Your Temperature Setting
If your thermostat won't turn off heat, check the temperature setting to the compare temperature. If it's greater than the room air temp, your furnace will keep operating until it reaches your desired temp.
Under normal conditions, an air conditioner running in a properly sized system should cycle for about 15-20 minutes before shutting off. This length of time allows it to cool the air effectively, reach the desired temperature, and then turn off to save energy.
If your air conditioning system won't turn off, there are most likely malfunctioning mechanisms, such as a faulty thermostat or fan limit switch, frozen evaporator coils, electrical issues, or incorrect thermostat or fan speed settings.
1. Faulty Thermostat. A faulty thermostat can cause your heating unit to run and not turn off. The unit may have a broken heating sensor, the wiring may have gone bad, or the switch itself may have broken.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
Incorrect settings on your thermostat or fan limit switch can cause the fan to run continuously. Faulty wiring or a broken fan limit switch can also cause your fan to keep running. You can diagnose and fix some furnace fan issues on your own. Faulty wiring or a broken switch will require professional repair.
Clean the Thermostat. Sometimes, when the room temperature doesn't match the thermostat setting, the problem could be dirt buildup on its interior parts. A dirt coating around the inner components may create excess heat and cause the thermostat to give the wrong readings.
Check the ductwork.
As air flows through your ductwork, seals and joints loosen. That can create leaks. Other leaks may also develop. Leaky ductwork makes it hard for your furnace to reach and stay at your set temperature, meaning it will run longer and more often.
Certain situations may require you to reset your thermostat. For instance, if it's cold outside, and you're cranking up the temperature for your furnace but the house still doesn't feel like it's warming up, you may need to reset your thermostat.
When the coils freeze, they can't efficiently transfer heat, causing your air conditioner to run continuously. This can be due to low refrigerant levels, poor circulation, dirty coils, power issues at the outdoor unit, setting the AC unit temperature too low at night, or power issues at the condenser.
Your HVAC system isn't sized properly
An HVAC system that's too large for your house will cool your home unevenly. It will only cool some rooms off and then shut off versus cooling down the entire house. On the other hand, an HVAC that is too small will have to work above its capacity to cool down a house.
Malfunctioning Thermostat or Incorrect Thermostat Setting
Your furnace could be running constantly because either your thermostat isn't set correctly or is malfunctioning and not properly signaling the furnace when to turn on and off.