Whenever an air conditioner keeps running when turned off, there can be several reasons.
Some reasons your AC keeps running when turned off could be because:
- Fan setting is “on”
- Your thermostat is malfunctioning
- Outside temperature is too high
- Air ducts are clogged
- Air filter is dirty
- Stuck relay switch
- Electrical problems
Read on to find out how to fix these issues when your air conditioner system keeps running, despite shutting it off.
7 Reasons Why Your Air Conditioner Keeps Running When Turned Off
1. Fan Setting is “On”
The fan inside your air conditioning unit may run separately from the cooling component of your AC unit.
The two components work together so they can cool your home; however, the problem is they may not shut off or turn on at the same time.
If your fan is set to the “auto” setting on your thermostat, it tends to only run when the cooling component of your air conditioner is running.
On the other hand, if the fan is set to “on”, rather than “auto”, it will blow air continuously.
Always double-check your fan setting before trying to diagnose any other issue. It could be something simple like a small setting error like turning it to auto position.
2. Malfunctioning or Broken Thermostat
Check out the temperature on your indoor thermostat and compare the thermostat that controls your air conditioner.
If your temperature in your home is lower than what you set on the thermostat, chances are it is broken or malfunctioning.
When a thermostat is not working properly, it won’t accurately gauge the true temperature of the room.
This causes the air conditioner to run nonstop or even turn on when it’s supposed to shut off.
3. Outside Temperature is Too High
If it’s hot outside, your air conditioner may not be able to keep up with the temperature that you set the thermostat to, causing it to run nonstop.
Air conditioners have to work extra hard when the weather outside is humid or the outside temperature is higher than normal.
Before you try to stress out over why your air conditioner keeps running when turned off, check and see if it’s just working extra hard from the temperature outside.
If that’s the case, the fan may stay going for a little while after you shut the ac unit off.
4. Check Out the Air Ducts
If there is a leak in your system’s ductwork, you can run into serious complications.
The air ducts can be found throughout your home as they bring cool air to different rooms.
Over time, a leak can occur. When a leak is present, it can lead to the air conditioner unit working harder than it needs to, causing it to continue running when you shut it off.
This is one of the potential problems that you may need an air conditioner expert to handle, or if you know who did your ductwork, they could promptly resolve this for you if it’s the issue.
5. When is The Last Time You Checked the Air Filter?
While this sounds like an easy solution, some people forget to check their air filters.
Between daily life and tasks, unless we write it down in our calendar, it’s easy to forget.
Numerous problems can occur from a clogged or dirty air filter, the most common being frozen evaporator coils.
Since your air conditioner needs proper airflow to work properly, it’s vital to check your air filter often.
You should replace your AC filter every three months (or less, depending on how often you use your air conditioner).
If you have allergies, then getting the right filter for allergies will help keep the air in your home clean.
6. Damaged or Stuck Relay Switch
Just like other parts of an AC unit, the relay switch can end up going bad.
If you shut off your window air conditioner but it keeps running, this could be caused by a relay switch that is damaged or stuck.
When that happens, the relay loses communication with your air conditioner fan.
What this means is that the fan stops receiving the command that you are relaying to the AC thermostat.
It’s best to have a certified HVAC technician to diagnose this issue.
7. Wiring Issues
If you have ruled out all the other problems with your air conditioning system, you may have some faulty or loose wiring going on.
If you’re not experienced when it comes to electric work, you should hire a local HVAC company.
It can be dangerous to try and figure out this type of work by yourself.
When Should I Call an HVAC Professional?
When you can’t figure out why your air conditioner keeps running when turned off, you may want to have a local HVAC company take a look.
If you’re not experienced with the parts of an air conditioning unit, it’s better to let a professional handle your cooling system.