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Problem: Air conditioner is freezing up. Seeing frost or ice on the suction line (black insulated line)

Happy AC

Problem: My air conditioner is freezing up. I am seeing frost and ice on the suction line (black insulated line) Any areas that are not insulated are covered with ice. My air conditioner is freezing up. You see frost or ice on the suction line (black insulated line) Any areas that are not insulated are covered with ice. You are not getting hardly any air flow out of your registers. Your evaporator coil is iced up completely.

Solution: Turn your air conditioner off and let the ice thaw out by running the fan (fan set to ON) on your thermostat. Thawing sometimes takes 2 to 3 hours.  Most of the time air conditioner freeze ups are caused by the system being low on refrigerant charge. Look for these causes for why the air conditioner is freezing up. Some thing that cause air conditioners to freeze up are:

1. Dirty air filter or some air flow restriction.
2. Dirty blower
3. Slow or dragging blower motor (might need a new capacitor). Please click here if you would like to see the capacitors we sell.
4. Dirty stopped up Evaporator coil (Need to have HVAC tech or you need to inspect and possibly clean evaporator coil)
5. Long Air conditioning run times. Setting thermostat below 72 degrees with cool outside conditions.
6. A stuck contactor that keeps the outdoor unit running even when the indoor blower is not running or when the thermostat is calling for cooling. Please click here if you would liked to see the air conditioner and heat pump contactors that we sell. Please click on this link if you are interested in viewing a YouTube video on how to change a contactor out: YouTube Video on how to change out a contactor.

Most of the time a freeze up condition is caused by a low refrigerant charge. Since the air conditioning system is supposed to be a leak free, a sealed system this means you have a leak somewhere. I use the Schrader valve caps to make sure that I do not have a leak in the Schrader valves when I take the manifold gauges off. I install these Schrader caps for insurance, because I have seen leaks in these valves many times. These caps have a rubber seal inside of them and insure a leak proof seal. Please click here if you would like to see the Schrader valve caps that we sell. Please click here if you would like to see the EZ Seal leak sealer we sell.  This sealer will circulate throughout your air conditioner or heat pump system and seal small leaks. Below we have a YouTube video that a company called HVAC Maintenance made that shows how to find leaks and install the EZ Seal Sealer. I hope this will help you solve your air conditioner leak problem.

Above, Schrader Caps Installed on an outdoor AC unit.

Below we have a YouTube video below made by David Jones that shows how to install the EZ Seal Sealer. I hope this will help you solve your air conditioner leak problem. We sell the EZ Seal Kit and Sealer on the following page: Please click here if you would like to see the EZ Seal leak sealer we sell.  Thanks so much HVAC Maintenance for taking the time to make this informative video!

10 thoughts on “Problem: Air conditioner is freezing up. Seeing frost or ice on the suction line (black insulated line)

  1. Hi Steve, I have a straight a/c packaged unit (2 ton) that runs fine for a few hours cooling nicely. The charge is correct, all capacitors are new, blower runs fine, filter and both coils are clean. It has capillary tubes and a copper spun filter dryer. My problem is that after a few hours the compressor and suction line get severely iced up and the unit starts blowing warm air. It does not appear as if the evaporator itself is iced up though. Super heat will just start randomly plummeting and then climb back up. Do you think there is a restriction in one of the capillaries? What else could it be? Thanks in advance for your time.

    Ken

    1. Hi Ken!
      Testing with gauges and watching the gauges to see what the pressures are doing should tell you what is going on in your system. If the suction pressure starts out right and then starts going down then you probably have a restriction in the system. This could be water that is freezing up causing the restriction or a TXV valve that is not working correctly. I would suggest going to the AC Service Tech channel and looking for YouTubes on restrictions in ac systems. Here is a link to some good YouTube videos: https://www.youtube.com/results?search_query=restriction+in+ac+system I hope you can easily find and fix the problem. Steve

  2. I have a ac unit that the pipes is cover with ice do I need to stop the ac and turn on the fan on the thermostate or let it dry on its own

    1. Turn your air conditioner off and let the ice thaw out by running the fan (fan set to ON) on your thermostat. Thawing sometimes takes 2 to 3 hours. Most of the time air conditioner freeze ups are caused by the system being low on refrigerant charge. Look for these causes for why the air conditioner is freezing up. Some thing that cause air conditioners to freeze up are:

      1. Dirty air filter or some air flow restriction.
      2. Dirty blower
      3. Slow or dragging blower motor (might need a new capacitor). Please click here if you would like to see the capacitors we sell.
      4. Dirty stopped up Evaporator coil (Need to have HVAC tech or you need to inspect and possibly clean evaporator coil)
      5. Long Air conditioning run times. Setting thermostat below 72 degrees with cool outside conditions.
      6. A stuck contactor that keeps the outdoor unit running even when the indoor blower is not running or when the thermostat is calling for cooling. Please click here if you would liked to see the air conditioner and heat pump contactors that we sell. Please click on this link if you are interested in viewing a YouTube video on how to change a contactor out: YouTube Video on how to change out a contactor. I hope this helps you find and fix the problem. Steve

  3. Hi everybody I had a service call package unit 5 ton 410a.
    Get freez up the suction line and the the compressor , I changed the filters and I cleaned the condenser, I cheated the blow is runing good when I measure the low side with my gauges suction. Line 65 psig and lequid line 325 psig I cheated the return is clean when I chard the unit I hear the compressor going bad it mean is overcharging , I don’t know the problems is the filter drayer or the txv

    1. Hi Karem! Sounds like a bad TXV valve. I heard that many of the manufacturers are having trouble with their TXV’s because of the rust inhibitor that Copeland is using in the compressors. The rust inhibitor reacts with the oil and causes a substance to form on the piston pin of the TXV and this substance causes a restriction inside the TXV valve. The follow is a good explanation of why so many TXV valves are going bad: https://www.youtube.com/watch?v=Amo2eRlYrzg Fast forward to 7 minutes if you want the explanation on the cause of the problem. Here is a link to some good videos on troubleshooting TXV valves: https://www.youtube.com/results?search_query=troubleshooting+txv+valves AC Service Tech has some real good videos. Rarely do filter driers get stopped up so I would think the TXV is bad. I hope you can easily find and fix the problem. Steve

  4. Thank you and you have a Blessed day aswell,

  5. I have a heatpump that has ice on the highside botton line on the core which the high pressure switch is. It start at highside charging valve and end at high pressure switch. no where else. auto heat blowing cool. This is heat setting auto.

    1. Hi William! There are many things that can cause a heat pump unit to freeze up in the winter time. Most of the time it will take a technician with gauges to troubleshoot and find what the problem is. Some of the causes for heat pump freezing in the winter are low refrigerant charge, faulty defrost control board, faulty defrost thermostat, stuck reversing valve, restriction in the refrigeration system and a slow or dragging outdoor fan motor. I would suggest that you have a service tech check out your heat pump. Sorry that I can not give you a DIY answer. I hope you have a Happy and Blessed New Year! Steve

  6. I will be happy to try and answer any questions you have. Thanks so much for your interest and support in our website! Hope you have a blessed day! Steve

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