[F16 1UB]

Aug 2010 our AC quit. There was NO readout on the thermostat. I called a repairman who came out & showed me what was wrong and if it ever happened again what to do.

Problem:

Drain was clogged causing water to raise float valve to shut down AC unit. Yeah the drain that everyone says to pour something corrosive in it to keep it clear. I don't care what you dump in the drain. Here's what to do to get the unit working.

Solution: TURN OFF AC BREAKER AT PANEL

Remove cap from the white PVC pipe at the furnace/AC inside. This is the area where you pour the drain cleaner.

Connect shop vac to the drain PVC pipe outside at the AC Compressor sucking water and anything else from drain pipe.

Final Step - Take a garden hose and insert it in the white PVC drain inside. Turn on full flushing anything out of the line. Go outside & reinstall shop vac to PVC drain line sucking all the water from the drain. Reinstall cap inside on PVC drain.

TURN ON BREAKER - *You should be able to see thermostat readout. Set as you normally do. THE AC UNIT MAY NOT START IMMEDIATELY. Give it 5-15 min.

*If your thermostat now appears normal, feel pretty confident in yourself that you've fixed the problem.

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[rubicon]

Thank you so very much.

[philnpat]

Thanks so much for the heads up...I knew that a clogged drain would cause a problem but didn't know what symptoms we would get if it ever happened. Thanks again!

[keithwand]

Del Air in Winter Park told me to flush the pipe with a cup of vinegar every month which I did for 8 years.
Long story short DON'T do it!
The vinegar ruined the condenser coils and I had to replace the unit prematurely.
Do flush often with a pitcher of warm water to keep the lines clean.

[ugotme]

My AC company told me to put about 1/4 cup or so of bleach in there once a month.
So far - 5 years later, no problems.

Just saying.

[LatDoc]

One additional step.
At any point in the process, use the shop vac to suck the water out of the pan that filled that turned off the air conditioner.
This is the pan that fills with water that automatically stops the AC as the float goes up.

[Rebel Pirate]

Originally Posted by ugotme

My AC company told me to put about 1/4 cup or so of bleach in there once a month.
So far - 5 years later, no problems.

Just saying.

We recently purchased our new home and earlier this month had the "Air Conditioning Orientation" with the vendor that installed the HVAC system in our home. He said to flush the line out (use a bucket of warm water and a funnel) a couple times a year. He said DO NOT UNDER ANY CIRCUMSTANCES use anything besides water...no vinegar, no clorox, no detergent....nothing besides water. He said there have been many instances where the liquid from that line gets sucked back up into the HVAC coil...if it's just water it's not a problem. If anything else mentioned above is sucked into the coil it WILL cause premature failure.

[Tom Grooms]

Bringing this back up as it saved me a service call. Outside AC unit stopped running, fan was still blowing and the temperature was rising. Cleaned a clogged drain and all is well. I just poured a few gallons of water and blew it out with compressed air. All kinds of gunk came out of the pipe.

THANKS!