Why Does The Evaporator Coil Freeze (And How to Diagnose It)

In this video Bryan covers why does the Evaporator Coil freeze and how to diagnose it. This is a great chance to learn air conditioning maintenance and troubleshooting.

Read all the tech tips, take the quizzes

[el_spaghetto]

Not only did I learn a lot, but I realized how much I _still need to learn._ 10/10 it hurts

[marka.devereaux]

Thank you for your videos. It's hard to find service oriented HVAC contractors. Your channel allows consumer, non-techs like me, understand the system better and ask better questions to make sure contractors are diagnosing first, providing solutions second.

[Bryan-Hensley]

After doing HVAC repair for 35 plus years the most common reason for evaporator freezing is too dense filters, second reason is dirty filter or evaporator, third reason is bad capacitor on fan motor, 4th reason is impacted blower rotor, and 5th reason low freon.

[CaliforniaEBRDude]

Thanks for the information, very helpful, and it confirms that doing anything other than changing the filter is way beyond anything I can do myself.

[danstarnes]

You are an inspiration to those aspiring to be ac technicians and those that already are but want to be better ones! Thank you for sharing your knowledge and experience in this wonderful trade!!

[ShannonLooper]

Grat video. I have a one ton LG window AC. It worked great for one or two summers then last year it started freezing up. Looks clean. I was just hoping I wouldn't have to get taps to check the charge, or just replace it. Great video!

[sammyg.]

If I may add one more thing here based on personal experience, check if air flow control board sends proper voltage to the indoor fan so that it runs at full speed. A Trane unit had bad control board where the fan was not running at full speed, hence low air flow. I followed the manufacturer’s troubleshooting guidelines to pinpoint what the problem was.

[Stuart]

An early lesson in running service. The suction line to the rooftop condensing unit was totally frozen and some of the body of the compressor. It was at a funeral home with a service in progress. I couldn’t find the light switch in the basement where the evaporator was and the blower.
It was running and blowing air. I defrosted and cleaned around the condensing unit. An experienced service man who was very familiar with this location knew right off the bat that the belt was slipping on the air handler in the basement without even turning the light on. He knew where the light switch was too. This so was embarrassing. I always remember this lesson about a freezing situation and also try to have adequate lighting if I’m going to inspect evaporator system.
thanks for your video it really covered a lot of aspects very quickly but they are all important and will help me in the future.

[Howie]

Have another cause of freezing and it is operator error. Used to work for a school district and in the old days we used standard thermostats at some locations sometimes without schedules or shutoff timers. Teachers would set the thermostats all the way down to 60 degrees, thinking that this would produce colder air (which it does not) and then forget to turn them off. During the daytime with a load on the system the room would not get to 60 degrees, but in the middle of the night the cooler outside air would drop the head pressure and the room would cool way down and drop the suction pressure and the coil surface would then start to freeze. It was a real good thing when we finally installed a computer-controlled system that defeated these clowns. Even with this we still had problems, like thermostats melted because lighters were held under them or even having heating pads pinned over them.

[danilogonzales]

Thanks, I have a Heat Pump with frozen evaporator and found out the fan blower got overheated and stucked. Hope this is the cause of my problem after replacement. Informative video keep posting.

[ralphruiz]

Thank for everything you do. I love watching all your videos and as a HVAC tech just starting out in this field they really help me a lot.

[marriagepartnersministry]

It's amazing that most sales oriented companies schedule a job every 2 hours. There's little chance one can properly check all the items you mentioned in 2 hours, much less perform repairs.

[Dtownboogieful]

As a new tech some these comments help aswell

[chrisnaden]

This video is very descriptive but way above my technical knowledge. I'm going to just call my local HVAC repair guy.

[Dancing_Alone_wRentals]

I'm very grateful all the effort you put into these videos.

[jimmyp]

If in commercial or kitchen equipment also check for cooling running with outdoor low ambient temps... check fan cycling controls or sensors motor masters etc etc... great videos people!! Can def get some great knowledge from these guys!! 🤘🤘🇺🇸🇺🇸

[benh]

Great video, now let's touch on limit switches tripping!

[flagmichael]

Our new HVAC began freezing up initially because the floor level intake coated the filter with dust from our dogs in about a week. With the advent of monsoon season here in Flagstaff the dust settled somewhat but humidity rose. At over 7000 feet, airflow is already at a premium. Finally, the zone system includes a very long 8 inch duct to the guest room, which demands cooling but only a wisp of air makes it through. Next step: I am adding a duct fan controlled by the damper for that zone. Don't know if it will be the final step in the fix but it should relieve the current issue.

On the plus side, we are very familiar now with the symptoms of icing, and our first step in dealing with it is to kill the 240V to the compressor. The second step is to swap out the filter if it has been in there more than two days. (We are now using a pair of K&N filters so there is no hesitation to swap them.) Half an hour gets the air moving enough to complete the defrost, which takes about an hour altogether. It could be a lot worse.

[saulurena]

Thank you! I like to start with airflow, and a lot of people who have more 'experience' always jump to an under charged unit

[shane]

Just had a call this week . HEATPUMP had 5 inches of ice on lineset, comp, and Ice was forming out of evap panel on to mfg label, RV got stuck in ac mode and wouldn’t free up !