AC unit outside fan stays on, won't shut off!


  #1  
Old 08-11-14, 11:27 AM
G
Member
Thread Starter
Join Date: Aug 2014
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
AC unit outside fan stays on, won't shut off!

Thermostat will read AUTO/ON. AC works great! However, the FAN on the AC unit outside will not turn off. Stays on continuous until you shut-off at breaker switch. How should I go about fixing this? Is it a bad thermostat or a bad relay?

Thank you for any help or suggestions community!Name:  AC1.jpg
Views: 15107
Size:  40.4 KBName:  AC2.jpg
Views: 17168
Size:  50.4 KB
 
  #2  
Old 08-11-14, 01:31 PM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,654
Received 90 Upvotes on 79 Posts
If you remove the thermostat (assuming it mounts onto a base), does the outside unit turn off? Also, is it just the condenser fan running, or is the compressor running as well? If both the compressor and condenser fan are running with the thermostat pulled, then it's likely a sticking contactor. If only the condenser fan is running, it might be a bad fan motor (grounded winding) if your outside unit has a single pole contactor.
 
  #3  
Old 08-11-14, 02:18 PM
G
Member
Thread Starter
Join Date: Aug 2014
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Will test the thermostat to see if the unit turns off when disconnected. Just the fan inside of the AC unit outside is running, not the compressor! What do you think? I am going to purchase a basic thermostat replacement and maybe that will fix it? Thank you
 
  #4  
Old 08-11-14, 02:29 PM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,654
Received 90 Upvotes on 79 Posts
If you remove the thermostat from the mounting plate (disconnect it), and the fan still runs, it's not the thermostat. Do you have a volt-ohmmeter? If it's not the thermostat, you'll probably need one to go much further.
 
  #5  
Old 08-12-14, 07:33 AM
G
Member
Thread Starter
Join Date: Aug 2014
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Due to heavy rains I was unable to stop at the local Lowes to pick up a new thermostat. Running the AC last night and the unit outside ended up making a loud electrical sounds like a rock was bouncing around the fan. I immediately shut off the AC main power. Still heard the electrical sound from the unit outside and realized the thermostat was still ON. I then turned the thermostat to OFF and the sound outside then stopped. Is the motor now broken?
 
  #6  
Old 08-12-14, 07:47 AM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,654
Received 90 Upvotes on 79 Posts
I can't say what was making the noise. All I can suggest is that you have someone turn the thermostat to cool while you're outside to listen to the outside unit. You should have a disconnect outside that will allow you to kill the power to the outside unit. If you hear the noise, listen to try to determine approximately where the noise is coming from and then disconnect the power to turn off the outside unit. Once the power is turned off, you can begin to check out the area where the noise was coming from. If you don't feel comfortable doing this, then it's time to call a professional technician to look at the unit.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: