3 most Common reasons Why Your Air Conditioner Freezes Up

Published 2016-06-28
It is the hottest day of the year and yet your air conditioner is freezing up. Mark Boissoneault from Tradesman Heating and Cooling shares with you the three reasons why your air conditioner freezes up and what you can do to prevent that from happening.

All Comments (21)
  • codster200
    So amazingly quiet and Fastly.Cool in my room! 42db is at a whisper level. I bought 2 and installed myself.Very sturdy bracket and easy to adjust to fit windows of different size. Absolutely fabulous units!!
  • kimberlindy
    Hi, thanks for the video! Is there a way to know how many pounds of coolant need to be added to a system to fully charge it, before the coolant is actually added? Do the gauges when checking tell you how many pounds low it is? Also...with a 4.5 ton A-coil, should I expect an HVAC service person to take it out and lug it upstairs and outside to clean it, or is cleaning in place what I should expect?
  • Dayo Makanju
    Thank you for the information shared. I have a question regarding ceiling concealed ducted split unit. There are 6 units installed at a light commercial building. 4 of the units serve an open trading floor while the remaining 2 serve a space. Based on the report given, there is a quarterly maintenance being carried for all 6 units. A year after commissioning the units, the cooling effect of the ACs drastically reduced (indoor temperature 26 - 27 degree celsius as against 22 - 24 degree Celsius initially observed) even after the scheduled quarterly maintenance. I was privy to be present during the last service carried out by the technician and the tasks carried our were (1) remove and clean the filters (2) wash the return coil fins with brush and water (3) wash the condenser (4) Check the gas level (60 psi on low pressure side for R22 system). My question is that are the steps enough to be deemed a good servicing. The filters were clogged heavily and when removed, there were lots of dirt on the return coil fin which makes me feel it will have penetrated into the unit over time. The speed of the fan is low when operational and the condenser shuts down at about 5 - 6 minute interval and starts after 3 minutes. The short duration of the condenser working is responsible for the high temperature observed in the space. In the little research i have done, i saw that the blower of the unit is supposed to be removed during each service. Kindly confirm this and add any additional suggestion.

  • Yes you are correct. A contactor or thermostat as well as a pinched wire that shorts out Y to R can all be a reason that would cause the system to stay running and over cool and freeze up the evaporator. There are a few other conditions also not mentioned here as well. My intention for this short video was simply to offer a basic explanation of what I consider to be 3 of the most common reasons that most homeowners might encounter.
    Thank you for your comment.
  • n4mwd
    Thanks for a good explanation. I have another reason for Ice-up on my AC unit. My digital thermostat was malfunctioning - turning on the compressor and not the fan. The lack of air flow that you mentioned freezes it up pretty quick. Thanks for confirming that the lack of air flow can cause icing.
  • Sonny2344
    This is by far the best video for simple minded people like myself for explaining the freezing problem on your a/c unit. Thank you very much👍🏼
  • Hello Mark! I just had a company told me I was low on freon and that is the reason why my coil was frozen. The technician advises me that I needed freon. He told me I needed at least 3 lbs. I knew it was BS. My air handler still leaking water on the backup drain line. There is barely water in my main drain pan. What do I need to do?
  • Brian
    Simple, Clear, Accurate, no blaring background music. One of the best posts I have ever seen on Youtube.
  • Mike Smith
    Mark thanks your video it was extremely helpful to me. At first when I took the cover off the evaporator looked clean. When I finally figured a way to remove the small cover, so i could see the inside of the evap the crud in there was incredible. I took a toothbrush and a Shop-Vac cleaned it. i wish i could have uploaded photos
  • Kuwaiti55
    Air flow restriction could be from less tension for the motor belt, which leads to reduce the RPM and cause less air flow.
  • Chris K.
    Thank you for your thorough explanation!  This was very helpful to us when we had difficulty with our a.c. unit.
  • Excellent video, blazing summer heat and the ac is constantly puddling water under the handler. I changed the filter and hosed down the a pillar which was full of dust(desperate maneuver). I check the drain line and it's clear. I think it's low refrigerant and me having the vent in the second bedroom closed completely. A combination of things. Great video thank you.
  • Flame Keeper
    In most cases it's all about thermostat malfunction. resulting the AC unit to operate without cutout. second is some leaking ( freon) in the system and third is that dirty air filter . Big thanks for this. man! From start to end you deliver it well and it surely does add some information. More power 😉
  • Miguel Juarez
    Thanks allot Mark and team, you just made me find the reason why my conditioner was freezing. It was both air bockage and a dirty filter. Thaks for sharing your knowledge to the world. Greetings from Monterrey, Mexico!
  • Nina Marquez
    My window unit started to freeze and I was freaking out because it's super hott!!!!! I live in central Florida and we are in the month of April and the weather has been crazy to say the least lol. I just wanted to thank you for this video it was very helpful and the instructions on how to defrost my window unit were easy to follow. You have literally saved my night!! 😂😂 Thanks again for the video!😉😀
  • Thank you so much. You just saved me a lot of money. I was about to call a tech and with your advice, i was able to solve it by myself. Keep it up sir
  • Harry Patodiya
    Very well explained. Wish you would be closer to us, I live in South West Virginia and purchased 22 wall thru PTAC units(heat pump) and brand new units are freezing up while running on the heat setting. Feeling helpless.
  • Carole Durand
    Thank you for this free information. Seems nothing’s ever free anymore. I had a new heating cooling unit installed in April, this is September and I can’t cool my place any cooler than 80. Finally, today a tech came out and fount it was frozen, no one ever looked before. Had seven service calls. My thought all along was that there is a restriction or a leak, because it’s colder in the crawl than the house. I don’t understand the a/c process,but, now I see why little clearer. Thanks again.
  • Sergio Trevino
    Great explanation and use of filter and part of evaporator coil to demonstrate. It was simple and not overly complicated. Thanks again Mark. May God continue to Bless your business.
  • Robert Hellewell
    Excellent video - 1 question I have a York Aircon installed approx 5 years ago. Always have clean filters, changed regularly. My fear is that the unit is "too small" for the house square footage. Its aYork LX YCJD 13 Seer. My house square footage is 1800 sq ft above grade. Of course the company that sold and installed it have gone out of business. It is freezing up even if I set it to 23C - any thoughts?