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HVAC issue HELP!

4K views 9 replies 9 participants last post by  hdavis 
#1 ·
Hey Pro HVAC'ers

I have a house I am working on and the AC unit is driving me crazy it is around a 2ton Puron/Carrier I believe. One air handler one condensing unit. The Heat is part is using Nat. Gas ( not heat pump)

The issue is that for 2-3 week the unit runs fine. Then the Air handler is running. The condensing unit out side is not on. Replaced contactor and Capacitor just to make sure they are fresh. When the out side condensing unit is not running and the air handler is running. Now its happening Pretty much all the time. The Air handler turns on the condensing unit sometimes turns on or does not but it will then only run about 3 minutes. Turn off breakers for about 20 minutes. Rinse repeat.

Is the FAN bad maybe pulling to many amps getting too hot? Compressor ?
The computer on the system messed up ? It is a 2 zone system with a damper.

FSCHRIS
 
#4 ·
Float switch?

Hey fschris
One thing you might want to check, is your AC system's drain, as it may be clogged.

Many HVAC contractors install a simple device up at the evaporator coil called a float switch, which is basically a water sensor that determines if the drain is backing up, and if it is, it shuts off the outside unit as a means to prevent the system from over-flowing any water inside your home.

Typically people see the same symptoms you describe with a partially clogged drain - The inside unit will run, the outside unit will periodically kick on and off. This may be due to the water level backing up, triggering the switch, and shutting off the outside unit. Hours later, the water level may recede, and depress the switch, which will cause the outside condenser to kick on, until the water level rises again, and sometimes this may not happen for a week or two depending on how clogged the drain is and how humid the indoor air is.

So before changing electrical components that may be OK, make sure you climb up in the attic and inspect the drain pan, and the drain lines, for any sign of water or rust which would indicate a clogged drain. Also try and determine if you're HVAC system has a float switch, so look for any type of device that may have a set of wires coming off of it attached to the drain line or the drain pan - Sometimes, if you got a nice tech, he may have put a sticker on your system that indicates there is a float switch located somewhere on the system, other times, you just gotta hunt them down, but they are typically near the drain pan or evaporator coil drain line as it exists the evaporator coil.

If you're drain is clogged, you need to clear it out.

It just sounds like a typical clogged drain call to me, people call in and describe exactly what you just did all the time and it turns out to be drain that's periodically clogging and unclogging.

Good luck!
 
#9 · (Edited)
Hey there, I had a similar issue with my AC unit, and it turned out to be a faulty thermostat. Have you checked that out yet? Also, have you tried cleaning the coils and checking for any blockages? It could be that the unit is overheating and shutting off as a safety measure. By the way, I used to live in Israel, and we had this awesome company called Fenix for appliance repair. I wonder if there's something similar in the US. Here's their website if you want to check them out: https://fenix.co.il/ . Oh, and I'm new to this forum, so please forgive me if I'm not following any unwritten rules.
 
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