HELP!! HVAC Problem

[pushkins]

Single story homes are commonly referred to as "Ranch".
If your AC is producing the correct amount of conditioned air (cool), and there are no major air leaks (main trunk line, you'd know if there were any, your attic would be much cooler...lol), then it is purely an insulation around the ducts and or attic ventilation issues.

[mlincoln]

Ok I have finally made it out here to TX. After getting the attic vented with attic fans (2) and having a digital thermostat installed, I am still perplexed. the thermostat is set at 65 and room temp is 78? The air pressure coming out of the vets seem low and the line (small metal pipe) from the AC unit to the home is freezing up? can you help please as to what the issue could be. Thanks. Upload pics attached of the line freezing over. Thanks

[pushkins]

The lines from the outside unit are, (large line- suction)(small line- liquid). The large line is supposed to be covered with black insulation. If the line is not covered it will freeze up. Get some Armaflex refrigeration insulation & re-cover it. Use 3-M electrical tape (33+) to seal the insulation over the pipe. You have to seal out the air from touching the pipe.

I also looked around and found this web page with an explanation and some ideas to help alleviate technician costs (by you being able to give him as much info. as possible).

Air conditioning freezing? Let's check out your unit and find out why.

[mlincoln]

any additional advice on why ac is not cooling? vented the attic, new compressor, no visible holes in vents or excessive cooling in attic, had ducts cleaned to remove any debris, but still not cooling house. had to buy two window ac to cool house. what could be the problem? the home warranty company says its the ducts, but also said ducts look good they are perplexed! Another independent ac guy says just replace the unit. But everyone agrees unit is fine.its only 10 yrs old. help please! Oh thanks for the infor rearding freezing up:-)

[HayZee518]

low freon will freeze the suction line - but unless you are an epa rated technician, don't touch it! r-12 and r-22 require epa licenses.

[HandymanTrainer]

I would use a laser thermometer to check duct temp at as many as thirty places along the duct....also, look for a humidifier which is running in cool mode instead of heat, or a UV sanitizer with the wrong bulbs installed...

HandymanTrainer

[HandymanTrainer]

Originally Posted by mlincoln

any additional advice on why ac is not cooling? vented the attic, new compressor, no visible holes in vents or excessive cooling in attic, had ducts cleaned to remove any debris, but still not cooling house. had to buy two window ac to cool house. what could be the problem? the home warranty company says its the ducts, but also said ducts look good they are perplexed! Another independent ac guy says just replace the unit. But everyone agrees unit is fine.its only 10 yrs old. help please! Oh thanks for the infor rearding freezing up:-)

Assuming the indoor coil is not dirty or frozen, if air flow seems to be slow, it is possible that the incorrect fan speed wire is connected to the cool terminal on the control board. Under normal conditions the BLACK wire should be energized in cooling mode. If indoor coild is freezing but high side pressure is high, you may have a line restriction which usually occurs at the orifice fitting filter screen. This will cause high high side readings and low low side readings despite a clean coil.

All of this should have been checked by a reputable technician who was not just trying to sell a new unit.

HandymanTrainer

[mlincoln]

I since had to leave TX but they finally found the problem. First, the condensor coil was filthy, however this was not the sole problem. The Pistons, according to the technician, were put in backwards and when he switched them the unit miraculously began to work. Well needless to say, I am ecstatic! Have you guys heard of this before? my tenant didn't know what pistons or where can someone educate me on this?