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OT AC icing up.

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  • OT AC icing up.

    The central air coils are icing up. I have all the vents open. What gives?

  • #2
    I have seen auto air conditioners do this.
    the position of the thermostat bulb on the evaporator core caused the A/C to run too cold.Causing it to form ice. The thermostat controls the valve that sprays freon inside of the evaporator core.When cold enough its supposed to shut the valve off.Reposition the thermostat bulb and recheck the duct temperature. Its not supposed to be freezing. Try setting it to a higher higher temperature. The thermostat bulb has a long tube attached to it going up to the control valve.


    • #3
      You might also clean the crud off the condenser coils outside and the A-coil inside the inside unit.

      Andy Pullen
      Clausing 10x24, Sheldon 12" shaper, Clausing 8520 mill, Diacro 24" shear, Reed Prentice 14" x 34"


      • #4

        Why not slap a door with hinges on it, and store your ice cold drinks in there?


        • #5
          If cleaning the coils and fan blades doesn't fix it, you may have a leak in the system.

          If some of the freon leaks out, the pressure drop across the expansion valve is more than normal, resulting in ice forming on the part of the coil nearest the valve. Since ice is an insulator, it will gradually form over the entire coil.

          That's what happened to my old system when the super-cooling coil became pourous because of corrosion. I got a few more years out of it by cutting out the SC coil and recharging the system, but it didn't work quite as well.


          [This message has been edited by winchman (edited 06-24-2005).]
          Any products mentioned in my posts have been endorsed by their manufacturer.


          • #6
            <font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:

            Why not slap a door with hinges on it, and store your ice cold drinks in there?

            I deserved that.


            • #7

              Hey, how did you make out with the Syncrowave 250?



              • #8
                It's in the house now. A very clean machine. I'm running #6 wire to the garage from a 60 amp breaker in the panel. Or I was till the AC started acting up. Right now that takes priority. if all goes well I'll have it wired in by sunday and let you know.


                • #9

                  Cool... When you get it all setup, post some pics of the damage it can do



                  • #10
                    We had the same problem a few weeks ago and called up the local HVAC outfit that we've used for service in the past. We seem to have a slow Freon leak that means re-filling every few years. The nice lady at the other end of the phone suggested checking the air filter and replacing it. Almost told her to send someone over anyway but gave it a shot.

                    The filter was pretty filthy, was replaced, and the A/C has been running fine ever since, even with temps in the high 90's.

                    I guess that HVAC place will be getting our next service call, too.

                    Mike Henry near Chicago


                    • #11
                      When I had this problem last year, it was resolved by cleaning the A coils in the evaporator (inside) unit. I purchased a gallon of the required chemical from an AC store in town that sells to individuals. It was similar but not quite the same as something like 409 etc, but designed for aluminum as well as minimal smell. It does require minimal rinsing. The house still did smell of cleaning agent for about half the day, though.

                      I used the solution, diluted per instructions, in a garden sprayer. After a few soakings, I rinsed the sprayer and used that to rinse the coils. If you decide to clean both the inside coil and outside coil, note that there are two different chemicals involved. The coil cleaner for the outdoor unit is much more aggressive, smells much stronger and requires a thorough rinse with the water hose. For that reason, be sure not to use it on the inside coil, as it would probably be much harder to rinse and the smell would not be tolerable, for me at least.

                      While you’re at the A coils, dump a little bleach down the condensate drain. My primary drain filled with algae and other muck and became blocked, resulting in the overflow drain being my savior. I try to do this twice a year and have had no problems since.

                      I'm sure there are other tricks of the trade, but these tips have kept my AC doing fine without professional service for years.



                      • #12
                        Yup, usually means the coils or filter need cleaning/replacement. Insufficient air flow = freeze up.

                        Paul A.
                        Paul A.

                        Make it fit.
                        You can't win and there is a penalty for trying!


                        • #13
                          Turning the 'stat way cold and/or letting the unit run all night will usually freeze up the coil. We find that a lot here in No. Idaho.


                          • #14
                            If your A/C iced up today.. Just turn it off for 2 minutes and it should melt almost right away

                            That's todays temp for the North East.


                            [This message has been edited by 3 Phase Lightbulb (edited 06-25-2005).]


                            • #15
                              I yard sailed a dehumidifier for my shop for $3.00. Brought it home and it did everything it was supposed to do but dehumidfy the air. took it apart found it clogged and powerwashed it from the reverse side. Worked great for about 1 week and now I experiance icing,melt off, icing, melt off in cycles. Still seems to get about 2 gallons of water from the balmy Buffalo area shop air. Does the iceing hurt anyting?

                              I need it because my airconditioner is 14.5K meant for a room twice the size of my shop. So, it cools the shop but don't run long enough to dehumidify it. The shop will eventually be large enough for the air conditioner! Right now it seems silly to have to run a dehumidfier and air conditioner at the same time! A lot of heat comes out of the dehumidfier.
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