AC just stopped working….looking for advice……
AC just stopped working….looking for advice…… Yesterday I turned on my AC and it does not blow cold air. I believe the compressor is kicking on, but immediately kicks off. I say this based on watc...
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tcamper - Keep in mind that the plug-in meter checks for 120 volts. Your 50 amp service has basically two 120 volt feeds when referenced to neutral. Wall outlets are wired from either of two 120 legs of a 240 supply. If you just plugged your meter into one outlet you are only checking one side of the electrical feed. It doesn't tell you anything about the other side of the supply feed and your AC might be connected to that side. Problems with the distribution panel, connectors, or extension cables can cause low or missing voltages on one side of the supply.
If you look at the document supplied by 2edgesword it shows the compressor uses a start capacitor and a PTCR. The PTCR acts like a solid state relay. The AC compressor has two capacitors. One capacitor is connected to the compressor start winding all the time (the run capacitor) and the second one is connected in parallel to the first as the compressor tries to start. The PTCR provides this connection. While starting the PTCR gets hot (from the start current) and increases in resistance to disconnect the start capacitor from the start winding. The first capacitor (run capacitor) stays connected.
Generally a compressor not starting is caused by one or the following: (1) low supply voltage, (2) bad start capacitor, (3) bad PTCR (or relay), or (4) bad compressor (least likely). I recommend that you check both sides of the power source (check to neutral) and make sure that they stay above 105 volts or so when the compressor tries to start and above 110 volts at all other times. If you know what side of 240 you AC's 120 volt leg is supplied from you can just check that side but I recommend checking both to make sure you get the right side. If that is good then you can try a new start capacitor. The PTCT isn't all that hard to test but if you aren't experienced in this work you might want to have someone look at if for you (or try replacing it). Compressors can fail mechanically (they seize up) or electrically (coils open or short). Again, if you aren't experienced in this stuff you probably should have someone look at it. Also keep in mind that loose or burned electrical connections can cause problems like this so you want to perform a good and careful visual inspection of the wiring inside the AC if you happen to take the covers off.
I typically hate to throw parts at a problem hoping to fix it, Depending on where you are, they might be both hard to find and expensive. And in the end if they don't fix it, you still have to pay someone to do the job. Sometimes though, it's worth the gamble. Hope this helps.
Mike
If you look at the document supplied by 2edgesword it shows the compressor uses a start capacitor and a PTCR. The PTCR acts like a solid state relay. The AC compressor has two capacitors. One capacitor is connected to the compressor start winding all the time (the run capacitor) and the second one is connected in parallel to the first as the compressor tries to start. The PTCR provides this connection. While starting the PTCR gets hot (from the start current) and increases in resistance to disconnect the start capacitor from the start winding. The first capacitor (run capacitor) stays connected.
Generally a compressor not starting is caused by one or the following: (1) low supply voltage, (2) bad start capacitor, (3) bad PTCR (or relay), or (4) bad compressor (least likely). I recommend that you check both sides of the power source (check to neutral) and make sure that they stay above 105 volts or so when the compressor tries to start and above 110 volts at all other times. If you know what side of 240 you AC's 120 volt leg is supplied from you can just check that side but I recommend checking both to make sure you get the right side. If that is good then you can try a new start capacitor. The PTCT isn't all that hard to test but if you aren't experienced in this work you might want to have someone look at if for you (or try replacing it). Compressors can fail mechanically (they seize up) or electrically (coils open or short). Again, if you aren't experienced in this stuff you probably should have someone look at it. Also keep in mind that loose or burned electrical connections can cause problems like this so you want to perform a good and careful visual inspection of the wiring inside the AC if you happen to take the covers off.
I typically hate to throw parts at a problem hoping to fix it, Depending on where you are, they might be both hard to find and expensive. And in the end if they don't fix it, you still have to pay someone to do the job. Sometimes though, it's worth the gamble. Hope this helps.
Mike
