Tip & How-To about Heating & Cooling

Why does my A/C blow little to no air, that's not cold, and how do I fix it?

Air Conditioner freeze ups cause an A/C to blow little to no air through the vents, and the air is usually warm.

There are three basic reasons for air conditioner freeze ups:

  1. Insufficient air flow
  2. Low Refrigerant charge
  3. Outdoor temperature
1) The two most common causes of insufficient air flow are dirty filters and under sized ducts. A dirty filter limits air flow which in turn allows the cooling coil’s temperature to drop below freezing. Replacing the filter, monthly, usually alleviates this problem. Under sized ducts will also cause the system to freeze because it also limits the amount of air flowing over the cooling coil. This results in lowering the coil temperature and allowing the humidity in the air to collect on the coil and freeze.

2) Low Refrigerant Charge. The refrigerant system teeters on a delicate balance. If the system is not charged correctly, the system will not function properly. This malfunction may result in the poor cooling output and/or freezing up. Only a qualified, certified service technician can properly test and charge a refrigerant system. Check your small high pressure line (should be hot) and low pressure line (should be cold, but not frozen).

3) Outdoor temperature. If temperatures are too low, the system will not operate properly, and freeze up may occur. The outdoor unit does not function well in temperatures below 60 degrees F. A special “ambient temperature” control must be installed to allow the unit to run properly in cool temperatures, or you may open your windows and save energy. If the A/C is set lower than 70 degrees F, special adapters are required to be installed.

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1 Answer

Left Vents blow warm/hot air when calling for cold air


Usually a sign of a faulty blend door under the dash.
The blend doors direct air thru the ac and heater core along with the upper and lower vents.

Sep 12, 2012 | 2009 Chevrolet Silverado 1500

1 Answer

our Dometic air conditioner freezes up & we have to shut off the compressor for a while until it defrosts.


That's right. There is no defrost cycle on a rooftop unit as they are so basic. They need a defrost regularly, especially when it's warm. Check the outside unit is clean and air gets through the vents ok.

Apr 22, 2012 | Dometic Rooftop RV Air Conditioner

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i turn on the a/c it stays on about three secomds and cut off.


Hi,
Usually when that happens the unit is low on charge...

Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool...

Air Conditioner Trouble - Review the Possibilities

heatman101

Sep 25, 2010 | Amcor PLM-14000E Portable Air Conditioner

1 Answer

why does my air conditioner in my car blow out hot air? one minute, it'll cool just fine and the next minute, it blows out hot air.


Assuming you are not low on freon:
I have seen this symptom caused by too much moisture in the system too, it freezes near the metering device which kills the refrigeration effect which makes it warm up, the ice melts and it starts working until moisture builds up and freezes which kills the refrigeration effect again.

Jun 02, 2010 | Whirlwind FH-778 Air Conditioner

1 Answer

i have a 3 ton goodman heat pump warm air is delivered from all the vents except for two which blows cool to cold air . help me , freezing im both bedrooms


if these are the longest runs from the air handler this can sometimes happen ,about the easest solution is to install a in duct heater into the duct feeding the rooms this is basically a set of electric coils installed in duct to re-heat the air going to the bed room

Jan 08, 2010 | Goodman CLQ36AR49 Air Conditioner

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