When I turn the air conditioning on in my house, air blows out of the vents but the air is not cool. The fan inside the outdoor A/C unit spins just fine as well but it seems that the compressor won't start. A few seconds after the air starts blowing out of the vents inside my house, I hear a short buzz/humming sound that lasts about half a second that I assume is the compressor trying to start. This buzzing sound happens about once every 15 seconds, so it seems like the compressor is still trying to start, but never does.
I have replaced the run capacitor in my unit (the only one I see) and it has not fixed the problem. Not sure if it matters but it seemed like before I replaced the capacitor, the compressor would only try to start once every minute or so, compared to once every 15 seconds after the new capacitor was installed.
The A/C circuit is never tripped in the electrical panel so it does not look like a short anywhere. I have also tested the resistance between all three terminals on the condenser itself and everything seems to be normal with readings between 0.5-2 Ohm depending on the pair of terminals being tested.
The unit was serviced last year and we were told we likely had a leak in the refrigerant system. We opted to have the refrigerant recharged and to try a sealant hoping to buy us a year or two longer. The unit is ~13 years old.
Make and Model: Armstrong Air Model no. SCU10B48A-7
Any ideas on how to get the compressor to run or what the problem might be?