Recently replaced the contactor on the ouside 5 ton compressor unit - the a/c inside comes on and shuts off the blower when thermastat preset temperature has been reached - the ouside unit continues to run. My thought is that the contactor points are locked in the closed position. Any ideas? Should I again replace the contactor?
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Multiple problems. Eliminate thermostat first. Remove face from wall and turn on breaker. If fan still runs you have a bad board or bad relay. If fan outside is running compressor should be too. These operate on same contactor. Verify you are getting 24 volts to coil side of contactor. If odf stops working and contactor remains pulled in you have a bad motor. If odf motor stops working the compressor will shut off due to overheating.
If the fan is not running is the compressor not running also...if neither is running the possible reasons are 1..no power to outside unit...2..bad contactor on outside unit.is this buzzing if it is this indicates no power...3 bad capacitor,do both compressor and fan humm then quit humming and hum some more...4 high pressure switch has shut unit down because fan wasnt running if compressor was running but not fan....if your unit has this there will be a manual reset button where the lines come out of unit...if compressor was running and fan was not...1 bad fan...2 bad capacitor.. if you do not have any electrical knowhow i would recommend calling a hvac tech to come and fix unit...Thanks
Sounds like your contactor has welded shut. Everytime your condensing unit turns on, you'll have a an arc of electricity across the contactor. Over time, the arcing causes to contactor to become covered in cardon. When it gets to a certain resistance across the coil, it will weld shut and the comressor and outdoor fan will run forever until the bad contactor gets replaced. If you know what a contactor is, it's a simple fix and the price is about $20 bucks. If your unsure about replacing it yourself, by all means can an HVAC contractor to replace it. 240 volts is not something you want to mess with unless you know what you are doing
I was leaning towards a bad contactor. Either sticking sometimes or not making good contact. I would inspect the contactor for pits or burn marks near the contacts. DO SO WITH POWER OFF of course...but, what's the reset button you are referring to?? I'm assuming this is a heat pump, please send model number!!
are you speaking of the outside fan or inside? compressor should be a little warm but not boiling hot. the unit could be low on freon. if low it will run a while but the compressor will overheat and shut off leaving the fan running by itself ouside. if nothing outside is running check power. if you have power check the contacted outside to make sure it's pulled in. contacters are bad about going out on goodman untis. Also ants can get under contacts.
No power to outside unit. Check to see if contactor on outside unit is pulled in. Most AC units inside have float switch. When the drain stops up it shuts off outside unit. Located in overflow or underneath unit. No Problem Rusty
open the service panel to check for control voltage of 24volts when tstat calling, The contactor should be pulled in, if contactor is down,and contacts appear to be clean, and the unit is still not running, it is a bad compressor. to test this unplug the black wire from the compressoror at contactor,w/ power off! Turn on power if fan works normally it's a bad compressor. However if you see a swollen split cap(5 wires to a soup can looking w/ the terminal C,F,and Comp), switch it first and start at square one.
You also need to consider the high pressure switch if its cycling on off on off.
If nothing is running outside at times you probably have a weak contactor coil that is not pulling the contactor in all the time. If the outside fan comes on but not the compressor, the compressor is over heating and shutting off on overload protection. This could be a dirty condenser coil, low on refrigerant, the compressor it's self. The compressor comes with a 5 yr. warranty.