Nothing works

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  #1  
Old 06-10-18, 03:56 AM
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Nothing works - Outdoor and indoor unit are not working

Hello,
If someone can point me in the right direction, I would appreciate it. I have a heat pump and whenever I try and call for cool, neither the inside or outside unit comes on. I am a seasoned maintenance guy with electrical experience, so I feel comfortable trying things, but I just want to be pointed in the right direction.

Thanks in advance for any assistance
 

Last edited by glwhat; 06-10-18 at 06:42 AM. Reason: Modified Title
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  #2  
Old 06-10-18, 04:46 AM
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Check the fuse on the control board in the furnace.
 
  #3  
Old 06-10-18, 05:07 AM
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The fuse shows that it is good. After I posted, I read one of the other posts about having a bad transformer. The symptoms that were in his post sound alot like what I have. I am going to check the transformer next and see if I have voltage in and out. From a logical standpoint, this would make perfect sense why neither unit is working and hopefully this is the case.
 
  #4  
Old 06-10-18, 01:41 PM
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Normally the fuse blows before the transformer but in the case of an AC surge or spike..... the transformer can open without blowing the low voltage fuse. Check for 120/240v to the transformer. Remember, there is usually a switch on the service door that cuts all power to the unit,
 
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Old 06-10-18, 02:02 PM
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Exactly what Pete said. Check simple easy stuff. You haven't mentioned it...but did you check breakers? Is it in COOL mode (if it has that). Verify power to stat if a modern LCD display type (easy, just pull batteries if equipped). Did it ever work? New to you system?
 
  #6  
Old 06-10-18, 02:05 PM
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Checked transformer

So I checked the transformer and I get 240v in but nothing out. So I assume the transformer needs to be replaced. I did some further testing in case the transformer went bad because of a short. I removed all thermostat wires from indoor, outdoor and thermostat. When I check between these wires on ohms, should I get a rainy? I get some kind of reading on all of the wires when checked between each other. To me it sounds like something is shorted or am I thinking wrong
 
  #7  
Old 06-10-18, 02:50 PM
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rainy??? What do you mean?
 
  #8  
Old 06-10-18, 03:00 PM
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Lol auto correct

I just re-read my post and "rainy" should be reading. When checking between wires, should I get any reading?
 
  #9  
Old 06-12-18, 06:13 AM
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Now information. I have checked the entire 24 volt circuit from thermostat to outside unit. Whenever I would call for cool on the thermostat, I would blow the fuse. Whenever testing the outside 24 volt wires, I had all wires connected on inside unit, but all 24 volt wires disconnected from outside unit. I connected each set one at a time and would check and see if the inside fan was still running. Whenever I connected the yellow, it blew the fuse. I decided to check for a short in that wire, so I took a spare wire, connected at the thermostat, inside unit, and then connected at outside unit and I still blew the fuse. My question is what could I check now.
 
  #10  
Old 06-12-18, 07:49 AM
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The Yellow wire is the one that goes to the outside unit (condenser/compressor). Since you've already tried a new wire, you can rule out shorted wiring from house to unit (animal chewing on wires). It's possible that you have a bad contactor. The contactor is a relay that turns the outside unit on/off. When the thermostat calls for cooling, it connects the Y terminal to 24VAC. The 24VAC activates the coil on the contactor, pulling down the contacts, turning on the outside unit. Sometimes the coil shorts to ground, thus effectively shorting out the 24VAC. To confirm, remove both control voltage wires from the contactor. They are normally connected to the side terminals on the contactor. Before doing this, turn off the 240VAC power to the outside unit. There should be an electrical disconnect near the outside unit. If the fuse doesn't blow with the wires disconnected from the contactor, the contactor is bad. You can pick up a new one quite cheaply.
 
  #11  
Old 06-12-18, 08:20 AM
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Removed 24v to contactor

I forgot to mention in all of my testing that I also had the 24V leads of of the contractor and it still blew fuse when calling for cool
 
  #12  
Old 06-12-18, 09:12 AM
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Unfortunately, you have me confused as to what you've tried. I would suggest you try disconnecting wiring in the following sequence until you find where the problem is:
1) Disconnect wire from Y terminal on air handler that goes to outside unit
2) Disconnect wires coming from house to outside unit where it comes into outside unit (wire nuts)
3) Follow wiring inside outside unit and disconnect wiring from any devices (pressure switches, timers, etc.)
4) Disconnect wiring from contactor coil
 
  #13  
Old 06-12-18, 09:27 AM
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I apologize for confusion

Steps that I've done

1. Removed all 24V from everywhere and checked for short across all low voltage wires.
2. Didn't notice any problem and connected everything back and started only the fan to verify 24V and everything was fine
3. While fan was running, I turned the thermostat to cool and then fuse blue instantly.
3. Removed 24 volt wires from contactor coil. Started cool and blew fuse.
4. Went to outside unit and disconnected all 24V wires, started fan and then cool and everything ran.
5. While in cool mode, started connecting pairs of wires and when I got to yellow, it blew fuse.
6. Tried a different color wire from thermostat to check for short, but this didn't help


Sorry for the confusion
 
  #14  
Old 06-12-18, 09:34 AM
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Originally Posted by glwhat View Post
Steps that I've done

4. Went to outside unit and disconnected all 24V wires, started fan and then cool and everything ran.
5. While in cool mode, started connecting pairs of wires and when I got to yellow, it blew fuse.
6. Tried a different color wire from thermostat to check for short, but this didn't help
4. What 24V wires did you disconnect in the outside unit?
5. Where did you start connecting pairs of wires, in the inside or outside unit?
6. You ran a new wire from the Y terminal on air handler to outside unit? If so, did you disconnect original wire (from Y to outside unit) first?
 
  #15  
Old 06-12-18, 10:02 AM
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Continued troubleshooting

4. What 24V wires did you disconnect in the outside unit?
The 4 pairs of wires from thermostat and indoor unit
5. Where did you start connecting pairs of wires, in the inside or outside unit?
I started with red on outside unit.
6. You ran a new wire from the Y terminal on air handler to outside unit? If so, did you disconnect original wire (from Y to outside unit) first?

Yes, I disconnected original wire
 
  #16  
Old 06-12-18, 10:10 AM
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Try disconnecting the wire that's connected to the Y terminal on the air handler (indoor unit) that goes to the outside unit, leaving everything else connected. If I'm understanding correctly, the fuse should not blow. Please verify this is true.
 
  #17  
Old 06-12-18, 10:22 AM
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Currently, I am not there. I will try this is just a while and will respond.

Thank you so much for the responses
 
  #18  
Old 06-12-18, 11:08 AM
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Yellow wire

I connected yellow at outdoor unit and disconnected on indoor that goes outside. Fuse did not blow
 
  #19  
Old 06-12-18, 11:23 AM
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OK, that's good. You've narrowed the problem to the outdoor unit. See my earlier message (#12). You've just done step 1, so start with step 2). Let us know how far you get before the fuse blows again.
 
  #20  
Old 06-12-18, 11:49 AM
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Checked outside

So I went outside and pulled the 2 yellow wires off of the board and I put them back on 1 at a time. Not sure why, but system is running. But I think I'll see problem come back
 
  #21  
Old 06-12-18, 12:55 PM
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Thank you

Thank you to everyone who had recommendations
 

Last edited by glwhat; 06-12-18 at 01:36 PM.
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