Why is my Air Conditioner’s Refrigerant Line Covered in Ice?

A Columbia tech explains

Let’s say you’re mowing the lawn or pulling weeds. You’re looking forward to finishing up your chores so you can head inside and enjoy a nice, cold beverage in your nice, cool home. As you’re working, you glance over at your trusty AC unit, and something looks… unusual. And by “unusual” what we mean is “frozen.”

Alarm bells go off in your head. “Oh. That can’t be good.” 

You’re right. It’s not good when your AC unit “freezes up.” But don’t panic! If you see any frosty bits on the refrigerant line (or anywhere else, for that matter), there’s plenty you can do on your own before you call us.

Step 1: Thaw your unit

Turn OFF your AC, turn the fan setting to ON, and wait three of four hours. We know, we know: Turning off your AC when it’s sweltering isn’t anyone’s idea of fun. But neither is causing massive (expensive) damage to your AC system, right? So give the poor thing a chance to thaw out.

Step 2: Learn some quick HVAC anatomy

When your refrigerant line is frozen, your indoor evaporator coil is probably also frozen.

The evaporator coil holds refrigerant, which is a liquid or gas that absorbs heat from warm air. (That’s right; AC units don’t really “add cold” to air; they actually “remove heat”!) If the refrigerant gets too cold, the moisture in the surrounding air freezes. 

So, why would refrigerant get too cold? One of two reasons: low airflow over the coils or low amounts of refrigerant. (Spoiler alert: These are the two things you’re going to check in a bit.)

Step 3: Review the don’ts

Damage to your HVAC system is costly and time-consuming. So as you’re going about your DIY business, make sure you avoid the following:

  • Don’t continue to operate your AC. Leaving your unit on despite the freeze-up may burn out the compressor and motor, which can lead to replacing the entire system. 
  • Don’t scrape or pick off the ice. You’re more likely to damage your equipment. Allow it to thaw completely and naturally.
  • Don’t replace refrigerant yourself. We’ll say more about that in a bit.

Step 4: Check for blockages

When it comes to frozen refrigerant lines, the best-case scenario is you have a blockage somewhere. Here are the places to check:

  • Air filters. Inspect your air filters and replace them if there’s any visible dirt. Check and replace as needed, at least once a month. 
  • Supply vents. Open all supply vents—the vents that blow air out. Yes, even in the rooms you don’t use.  
  • Return vents. Unblock any return vents—the vents that suck air in. These are most often blocked by furniture or curtains. 
  • Dirty coils. Blockages can also happen on the evaporator coils themselves. If you’re mechanically inclined, you can carefully clean them yourself with compressed air, a brush, or mild detergent and water. Check your owner’s manual for details.

Step 5: Check your refrigerant

Despite conventional wisdom, refrigerant doesn’t get “used up.” That means if you’re low on refrigerant, you have a leak. 

Ice on your refrigerant line is the #1 sign of a leak, but here are some others to pay attention to:

  • Higher-than-normal energy bills
  • Air coming out of your vents isn’t very cold
  • Bubbling or hissing noises from your HVAC unit

If you suspect a refrigerant leak, do not attempt to replace it yourself. It’s a toxic chemical that should be handled by MasterTech, Columbia’s HVAC pros to protect your safety. 

Step 6: Give us a call!

If your AC is acting up and none of these quick fixes did the trick, we’re happy to help diagnose, treat, and prevent future problems. Give us a call today!

We found a leak underneath our kitchen sink and was not able to turn the water off. A MasterTech technician was there within an hour. He was courteous and professional and gave us a couple of repair options. Everything he needed, he had with him and the new valves were installed quickly and he was gone. Great repair experience!
Lorry Myers
Lorry Myers
21:01 27 Jul 20
Technician was timely, professional and courteous. He made sure I understood what was going on. And how best to move forward
Zane Whorton
Zane Whorton
19:15 16 Jul 20
Tyson was incredibly kind and helpful. He came out on a Sunday to help with a stubborn shower cartridge. I would recommend him to anyone needing plumbing help!
Courtney Jorgenson
Courtney Jorgenson
16:21 14 Jul 20
Very prompt, efficient, polite, and professional. Knowledgeable of needs and recommendations fit my circumstances. Thanks!
Nathan Mozingo
Nathan Mozingo
18:02 13 Jul 20
Master Tech replaced my ac/heating unit a couple of years ago and we have been very pleased with the follow-up checkup services we receive. Always very professional!
Joanne Nelson
Joanne Nelson
19:57 10 Jul 20
Tyson was very helpful and gave us advice for the future on how to save a little money with a project. We were very happy with him and his advice.
Wesley Dahms
Wesley Dahms
19:17 10 Jul 20
Josh Burleson installed our Home Depot purchased water softener. He was on time for the appointment, very professional and addressed all our questions. He was very neat in his work and cleanup. We would highly recommend calling MasterTech and Josh for all your needs.
Bette Everman
Bette Everman
22:48 29 Jun 20
Professional, personable and informative! I am on their yearly Check-Up plan for heating and cooling. Great price for a GREAT service.
Dorsey Ragland
Dorsey Ragland
17:55 29 Jun 20
Devon W. was a pleasure to work with. Efficient, clean, knowledgeable. Happy to have me sit with him while he worked so I could ask random plumbing questions that have always intrigued me. Highly recommend this business and Devin!
Pete Goodman
Pete Goodman
19:17 18 Jun 20
Chad arrived promptly when I was notified he was in route to my house. He was very friendly and professional and keeping social distancing practices. He was able to give options to get the result I needed. The cost was lower than what I had in mind and was completed in about an hour.I felt bad for him because it was hot and humid today (about 90) and the issue was outside of the house in direct sun...I set up a patio umbrella to cast some shade on him while he worked.Thanks again Chad! I will be calling MasterTech Plumbing for any other plumbing issues that arise!
Alen Petty
Alen Petty
18:22 03 Jun 20
Isaac and Alex removed a dead snake from my AC unit. They were professional and kind with a great sense of humor given the situation. They checked everything out to ensure it ran correctly and gave me an upfront price. I was quite satisfied.
Katie Ensign
Katie Ensign
17:54 01 Jun 20
Josh was so awsome! I had a "simple" leak in my faucet. He got the parts from his truck and fixed it like new, which is saying a lot as this faucet is over 10 years old. Very knowledgeable and friendly!
Betsy Kuhn
Betsy Kuhn
22:24 28 May 20
We had a great experience with Mastertech Plumbing from the time we made the phone call to request service. Our plumber Tyson was friendly, knowledgeable & professional. I would highly recommend this company & him for any plumbing needs.
Jamie Hogan
Jamie Hogan
17:40 22 May 20
I had a clogged drain that needed professional assistance. MasterTech was able to get Devin out to my house to fix our issue in record time. Devin was great and very professional and made sure the issue was fixed, the work area was clean and that I was satisfied with his work before he left. I highly recommend MasterTech.
Jeffery James
Jeffery James
17:01 08 May 20
When I called, the phone was answered by a pleasant service representative that remembered me and was understanding to my immediate need. MasterTech Plumbing tech Chad was very professional and friendly. He kept me informed of all what was wrong and didn’t try to up sell anything. I really appreciate Chad’s skillful knowledge. The quality of his work is exceptional. I know I can rely on Chad and MasterTech Plumbing.
Angela Hernandez
Angela Hernandez
02:12 08 Apr 20
The service we received today was awesome! Punctual, efficient, and up front and honest about prices and what products that we needed. Excellent work.
Cole Stoecklein
Cole Stoecklein
14:52 18 Mar 20
Josh is great! He is the one who usually comes to our house. He installed an overhead tank toilet, which is a tricky and time-consuming job. He overcame many obstacles and stuck with it until the job was completed and done right. Price was also good. MasterTech has always taken care of all our needs in a prompt and professional manner. Emergency service has always been rapid too.
Michael Lewis
Michael Lewis
17:24 11 Mar 20
Chris was great. Dispatch was great. We were scheduled quickly. Prices were very competitive. Edit: We had great success having our pipes fixed. Due to Missouri weather things were touch and go but Master Tech sure delivered! We are so please with the fix, financing and friendliness Master tech and our technician Chris Gilpin provided us. Will forever and always us Master tech. Certainly mighty nice people
Kimberly Threatt
Kimberly Threatt
01:30 29 Feb 20
We had to have emergency service today, Saturday. A serviceman was here in less than an hour. The repairs were made quickly, the charge was not over the top, even though it was not a work day, and the individual was friendly and courteous. We have learned to expect this kind of service from Master Tech. Thank you.
Barbara Timbrook
Barbara Timbrook
03:48 26 Jan 20
I recommend MasterTech. They show up when they tell you they will show up. They provide a comprehensive estimate and also a good explanation of the work that need to be done. Their work is good quality. They usually have the needed parts on their truck so they can do the task in a timely manner. They clean up the work area after the job is finished,
Dennis Catlett
Dennis Catlett
22:15 23 Jan 20
A great experience. First, on time, service tech was sent out when promised. Second, quick assessment of the problem (faulty sump pump). The tech not only quickly replaced the pump, but he made an alteration that will make it easier whenever a replacement has to be made. Bottom line, a most professional service. Certainly would recommend Master Tech to folks needing their service.
W B Tichenor
W B Tichenor
16:08 31 Dec 19
MasterTech is so great to work with. They're quick, clean, do great work, and have fair pricing. But the best thing about MasterTech is their people. Whoever is responsible for their human resources does a terrific job of selecting and/or training them. They're so friendly and provide excellent information and customer service. I highly recommend MasterTech!
Jason Black
Jason Black
20:37 26 Dec 19
Previously I had not been impressed with master tech. However, their technician Dillon not only fixed my emergency pipe break at 1am on a holiday but also saved me as a customer. This was the best service I have ever had at my home. He arrived promptly at 1am. Provided a couple of options on how to fix my problem both in the short and long term and quickly made repairs. He also has provided advice on how to address issues related to the water damage caused by the busted pipe. This was one of the most positive bad situation we have had as homeowners. Thank you Dillon and mastertech.
Michael Grote
Michael Grote
20:35 26 Dec 19
I had to change my appointment at the last minute and they were able to accommodate my new availability without any hesitation. My tech was really professional (Dillion). I got a call and a text to let me know he was on the way. He fixed my problem quickly and was so friendly. This is the second time that I have had to use a plumber and I will use Master Tech again since I have an old house with old plumbing.
Leigh Burton
Leigh Burton
14:01 22 Nov 19
HVAC and plumbing under one roof, what else do you need?! Great team!
CJ Roe
CJ Roe
01:06 30 May 18

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