Central air conditioning system not working? Well depending on what type of system that you have there could be a hundred reasons that your air conditioning is not blowing cold air. If you are living in a hot and humid part of the world, there’ s a good chance that your condensate drain line may be clogged, or that you may have a bad run capacitor.
I would estimate that 30-40% of the no-cool calls that I run in Florida are due to clogged condensate drain lines tripping a water safety switch. Unlike most Hvac repairs, this is something that may be fixed by the homeowner. Clogged condensate drain lines can also be prevented through a preventative maintenance program, which just about every major Hvac company out there offers.
How to Clear a Clogged Condensate Line
I have read many articles on troubleshooting clogged condensate lines throughout the internet and many people recommend bleach to clear a clogged condensate line. The truth is this rarely works and are going to need something much stronger. Bleach also can back flush into your air handler and weaken the copper tubing in the evaporator coil. While bleach may be a option to pour down the line to prevent algae growth, I wouldn’t recommend it as it can damage your equipment if not administered properly.
If you are able to locate the condensate drain line outside you may be able to clear it by yourself by either back flushing it with a garden hose, or hooking shop vacuum up to the line, which in some instances can clear the clogged condensate line. If you are back flushing the line with a garden hose just be careful because once it’s unclogged it will go back up to the air handler and could make a mess. If you are in a condo that has multiple floors and share the same line, well, you can make a mess for your neighbors also.
If this doesn’t work it’s best to call an Hvac repair man or plumber, as they have chemicals that are approved to be used in condensate drain lines, and will be able to cut the pvc if needed to blow some nitrogen through the line.
Bad Run Capacitors
The other calls that I constantly get are bad run capacitors on the condensing unit. Some symptoms of a bad run capacitor would be that the air handler is running, and the outside unit is not, but is making a loud humming noise. If you were to take off the service panel (which you shouldn’t unless qualified) and the capacitor is swollen up like a frozen soda can, then the run capacitor needs to be replaced.
If the capacitor is just weak, and is below the 6% MFD rating, then it will have to be replaced. One simple way to check the Microfarads on a capacitor is too use an electricians meter that is capable of doing so. If you are an Hvac technician make sure that you have a multi-meter or two in your bag that is capable of measuring the correct MFD.
If you are a homeowner and think that you can make this repair yourself – keep in mind that you can destroy your system if you don’t get the right sized capacitor. Just because the one in there was a 35+5 dual run cap doesn’t necessarily mean that’s the correct one for your compressor and fan motor.
If you hook it up wrong you can also cause damage to your equipment or seriously injure yourself or worse. Plus things can get even more confusing should you have a hard start assist with a potential relay. So please leave the replacement of capacitors up the professionals. Sure a you could save $100 or more by doing it yourself and ordering the part online, but remember professional service technicians replace these daily and know what they are doing and know what to do when something goes wrong.