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  • Home HVAC problem

    Normally when I have an AC problem I call a sub that I use due to the fact that I cant deal with freon. I had one yesterday that wasn't coming on but was getting 220. Called my AC guy and he said it was probably a bad transformer and he would bring me one. he gets there and we tested the trans and it was putting out 28v. He found the 3a fuse on the 24v circuit board blown. We didnt have any replacments so he put a jumper in just to see if it would work and it did come on and run no problem (only let it run about 5 seconds). I didnt like the jumper idea but he assured me that if it did any damage it would be to the transformer and he would replace it. After he left I got some fuses and changed it out. Every time I flip the breaker on there is a 2-3 second delay and the fuse pops. Weve inspected all of the low voltage wiring that is visable and it all looks good. Any ideas what to look for or how to test things?

  • #2
    Re: Home HVAC problem

    Originally posted by futuresweets10 View Post
    Normally when I have an AC problem I call a sub that I use due to the fact that I cant deal with freon. I had one yesterday that wasn't coming on but was getting 220. Called my AC guy and he said it was probably a bad transformer and he would bring me one. he gets there and we tested the trans and it was putting out 28v. He found the 3a fuse on the 24v circuit board blown. We didnt have any replacments so he put a jumper in just to see if it would work and it did come on and run no problem (only let it run about 5 seconds). I didnt like the jumper idea but he assured me that if it did any damage it would be to the transformer and he would replace it. After he left I got some fuses and changed it out. Every time I flip the breaker on there is a 2-3 second delay and the fuse pops. Weve inspected all of the low voltage wiring that is visable and it all looks good. Any ideas what to look for or how to test things?
    I had the same problem. Does the fuse blow when anything turns on, or does something in particular kill it? I had the problem where the fan would not blow the fuse, but the compressor would. Turned out that there was a short in the line from the control board to the compressor. You can use a multimeter to check for a short there.

    The tech had a really cool circuit breaker (he called it a resettable fuse) so he didn't blow through fuses while debugging the problem.

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    • #3
      Re: Home HVAC problem

      Originally posted by cpw View Post
      I had the same problem. Does the fuse blow when anything turns on, or does something in particular kill it? I had the problem where the fan would not blow the fuse, but the compressor would. Turned out that there was a short in the line from the control board to the compressor. You can use a multimeter to check for a short there.

      The tech had a really cool circuit breaker (he called it a resettable fuse) so he didn't blow through fuses while debugging the problem.

      I dont know what is popping the fuse, but it pops before the 7 second delay on the fan so I would assume it would have to be the low voltage wire going to the compressor, but that still does not eliminate the wire going to the thermostat.

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      • #4
        Re: Home HVAC problem

        Buy a handful of fuses. Unplugged all the wires from the control board. Plug one back in at a time until fuses blow. That should narrow it down.

        Comment


        • #5
          Re: Home HVAC problem

          Originally posted by futuresweets10 View Post
          I dont know what is popping the fuse, but it pops before the 7 second delay on the fan so I would assume it would have to be the low voltage wire going to the compressor, but that still does not eliminate the wire going to the thermostat.
          A simple way to check if it is the fan or the compressor is to turn your t-stat to fan only, and see what happens. If it starts up and runs OK for a while, you can then switch it from fan only to cool; and expect the fuse to blow.

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          • #6
            Re: Home HVAC problem

            If its blowing only on a call for cooling you probably have a bad contactor. If its blowing with the stat in the "Off" position I would still have to suspect a stat wire problem even though you said you inspected all the low voltage wires. If it blows with the stat wires disconnected from the circuit board, you more than likely need a new board.

            Andy

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            • #7
              Re: Home HVAC problem

              Sounds like a shorted contactor coil in the outdoor unit or a shorted fan relay in the air handler. Whole lot easier to replace low voltage fuses rather than transformers.
              Later, jonesy

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              • #8
                Re: Home HVAC problem

                I messed with it a little more yesterday and found out that with the Yellow wire disconnected it comes on fine, but as soon as the yellow gets connected back it blows the fuse. I checked continuity in the wires running from the air handler to the compressor and they arent shorted. I can only conclude that something inside the compressor is shorting and causing it. From what you guys say it does sound like the contactor coil

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                • #9
                  Re: Home HVAC problem

                  Is the condensor a newer Goodman? Like a GSC13?

                  Andy

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                  • #10
                    Re: Home HVAC problem

                    You need to replace your contactor, it sounds like it is the coil on the contactor. If there was a problem with the compressor it would be tripping the breaker not blowing the low voltage fuse.

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                    • #11
                      Re: Home HVAC problem

                      Originally posted by Ruudacguy View Post
                      Is the condensor a newer Goodman? Like a GSC13?

                      Andy
                      Its a little over a year old and it is a goodman, I went to the one across the street to borrow the contactor and it was burned looking (same kinda unit).

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                      • #12
                        Re: Home HVAC problem

                        I have replaced several Goodman contactors and Im not even a Goodman dealer. I cant imagine how many the guys who put this stuff in everyday are replacing. Theyre cheap for a reason.

                        Andy

                        Comment


                        • #13
                          Re: Home HVAC problem

                          disconect contactor in condensor . could be shorted.

                          Comment


                          • #14
                            Re: Home HVAC problem

                            Originally posted by Ruudacguy View Post
                            I have replaced several Goodman contactors and Im not even a Goodman dealer. I cant imagine how many the guys who put this stuff in everyday are replacing. Theyre cheap for a reason.

                            Andy

                            Well, it was indeed the contactor. Thanks for all the help guys.... Im glad I got if fixed but most of all im really happy about how much more I know about these systems now

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                            • #15
                              Re: Home HVAC problem

                              Another happy customer.
                              sigpic

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