We have had a coleman central air system for 5 yrs. It stopped blowing cold air into the house about a week ago. You can still here it running but no air is coming out. my husband replaced the fuses and over night it did the same thing so when my husband went to check out the unit outside he said that the line had ice on it. Is there a filter within the central air unit that needs replaced?

either the compressor is not running or you have a leak and are low on freon. the outside fan running does not tell you the compressor is running.

The AC unit outdoors must be running and rejecting heat by its air flowing through it the 2 copper lines are the refrigerant lines, the fatter one should be "beer can cold" if not its low on refrigerant or not running.

Check the compressor capacitor. It would have gone weak. Replace with the identical value and type.

Check the air filter and clean. If you can, raise the blower speed up to the next speed. Make sure all of the supply and return grills are open. Is the ductwork connected under the home and well insulated? Does the furnace ever stop or keep on running? If it does stop, you may have a bad thermostat.

your indoor unit is only circulating the air in the house. for your condensing unit. check your breaker in the electric panel. your contactor or your capacitor.

The only thing that is going to but the fan off is the thermostat. When the fan stops, immediately check the thermostat on the wall. See is there is power between the B terminal and the GH terminal. If none, then replace the thermostat. If there is, then replace the control board in the AC. That means that the fan relay on the printed circuit board is weak.

make sure the system switch is in the cool position, then press run program button and allow a couple of minutes for system to cycle on, if it doesn't come on press the button for lowering the set point, set it to 72 degrees and then press the hold temperature key.

The filter is located before the blower if your Coleman is in a mobile home it will be in the door facing. If it is a standard ac/heat application and a regular residential furnace the blower in the cabinet on down flow (ducts in floor) will be above it and possible in the duct connecting in the top. If its the other way (ducts in ceiling) it could be right under the blower. Either of these could have a filter cabinet on the furnace or could have a filter grille at the end of the return air duct (where the air is sucked in).

Change your heating delay to shut off sooner, you can find this in the installation manual. Also the Thermostat may have delay after heat as well. It is true there could be many variables, but it also sounds like the Heatpump is not charged properly, you will have to have a different tech come out and check that. No need to have the installer mess your system up any further. This solution will only correct the auxilary heat, your heat pump on the other hand will require expert skills.

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Thank You