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

This was a very good video

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.

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!!

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.

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.

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.

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.

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!! 🤘🤘🇺🇸🇺🇸

Always informative and interesting to watch. Another great video. Thank you.

Subscribed, great info. Clear, to the point. Great job!

Excellent information. Always learning something.

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.

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

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

Excellent video a bit of rush but has the correct information, Thanks

Great video. Thanks so much for sharing!

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.

Always great video. This one was chilling

Great tips Bryan.

Great video like always thank you for sharing your experience with all of us 👍🏻🍺

God bless you for this good film

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

Great info. Tips. Thanks Bryan.

Great 👍 job explaining.Thank you

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.

Thanks Bryan!

I like this video. The speed and content is amazing.

Great job and video like always

Very good presentation.

As always, his videos are the best.

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.

I have used head pressure control to successfully stop ice. (Orface no txv) 24x7 server room acs. Florida does not get cold enough to

Amazing, well organized presentation, clear explanation.

Yup, I needed a lot of pictures to watch this vid. But seriously, it is a very good vid.

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 !

As a new tech some these comments help aswell

Very helpful video. Thank you : )

Muchas gracias por enseñar

Great video. My suction line is frosting up. Indoor temperature is 75F and outdoor ambient is 70F. It's r410a with low suction pressure. The low side saturation temp is 28F. I am getting low superheat but normal subcooling with fixed orifice. Filter is clean and air flow is good. The coil has no frost but frosting just before service valve at outdoor condenser. All amp draws are good. I tried adding some refrigerant but the low side pressure would not rise. I just can't figure this one out. Any help would be greatly appreciated. Thank you.

Great video I would like to see videos on mini split systems

Thanks for sharing

Very Nice information good to see!

can you make a video taking about how to identify improper components sizing in refrigeration system

Over the last three years I’ve diagnosed at least 100 freezing coils, all of them being poor airflow and/or low refrigerant. Last week had one that stumped me, a mortex down flow in a mobile home that had perfect refrigerant pressure, lsat, vsat, subcool, airflow, delta t, etc. but was freezing up sporadically. Turned out it was a 3 ton coil on a 4 ton condenser.

Love your content!!

I had one occurance many years ago and some electricians were working on a pannel and when they reattached the wiring they riversed the direction of the blower motor. It was a three phase setup. I scratched my head a while on that one. US Navy 1977.

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.

You sound intelligent and spout intelligence. Intelligent video. Thank you!

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

Thanks from Bangladesh.

Good commonsense information, thanks.

Air flow is always good to check out

this channel Kicks ASS!!!

My favorite channel

Great video

Thanks for sharing your knowledge

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

Good job.

Good info 👍🏻

Enjoy your videos Great job😜

great content thanks

Thanks you're the best.

don`t to look for duct work errors. back in the 90`s went to a house, 2.5 ton low air flow, pulled down the attic stairs looked at air handler with 65 feet of 14 inch flex duct on the return, closed stairs and told her the duct crew will be over to straighten it out shortly.

I have a unit in my attic , I wanted the a coil cleaned . I called a HVAC company to do the best task, he was up there for 1 hour. And the secret hidden camera I had up there recorded fed him sitting down occasionally running his drill into empty air , tapping occasionally with a screw driver on the metal, ran the vacuum motor but not actually vacuuming any thing he was on his smart phone the entire time. I was charged 209.44 for nothing, I showed the video to him he said he was going to sue me for recording him without permission, later in the week I got a check for 225.00 back Wtf??

Great video. Another thing to check is the evaporator blower motor. Is it seized? Does it get power? Bad Transformer?

Can icing cause the blower speed to fluctuate a lot but mostly run at very low speed? This is a problem I’ve been having during a recent spell of hot weather. Usually turning the system from cool to off for a while fixes the problem and then it’ll work fine again for a day or two. If I leave the system off but the fan on, it seems to blow at the expected constant low speed.

Just flip into heat thawed in minutes just make sure condensate isn’t clogged or you’ll flood the evap..........

Thanks man.

Hi. Thanks for the video. We have a Magicpak unit in a closet in our condo. It's dripping water in the closet and down the outside brick when it's in AC mode. It's new. Filter is new. Installer says he needs to contact the manufacturer. Very frustrating after $7,500. Any experience with those magicpak combo units? Thanks.

on a variable speed compressor like the bosch (25%-110%) ids 1.0 ; should the system be put into force mode (100%) before you test the temperature difference? for me in regular mode when its about 50%-70% compressor running load the Temp Delta is about 5-6 degrees however if I put it in force mode its under 2degrees. Manufacturer says it must be in force mode in order to be able to charge. I am assuming the same holds true for the Liquid line temp difference across the direr? is that true?

How would you go about check the charge on a package unit where would I hook up my temperature clamps to properly check sub cool and superheat some units are kind of unacceptable unless you remove the condenser fan motor and scenarios like that?

Thank You

We learned our condensation line was dripping under the house into our crawl space. In an already poor soil (Adobe western Colorado) we didn’t like all that moisture down into foundation. We had an evap line ran from the existing down to a pump that kicks on when it’s reservoir is full and pushes the water out a drain line away from foundation. Since having that installed by an AC guy, his idea actually, our coil froze up and the blower pushed so much air past the coil and it literally knocked the lower cover door off the unit. Is there a connection to this Evap line setup and this freeze possibly? Also have no idea how long it’s been since coil was cleaned. We bought in 2015. Had an ac service/tune up spring 2020. Dunno if they cleaned coil or not. I know they did not remove it. It’s manufactured home and model number for coil is mbc48dqd. Coleman unit. Thanks for any pointers.

It’s all about the airflow.

Not related, but I went in a call for no heat at a preschool and found the classroom return blocked by a bunch of plywood. One HVAC company was the next door neighbor to the customer.

I do know when its 90 out and humidity approaches 95%….It becomes much easier for the “A” coil to freeze up, if it does, turn on the heat!!! Takes very little time to THAW out the coil and dry it out, works!! And then let the compressor cool down as well.

Fair warning- if a blower wheel has been dirty long enough, you can KO the motor once you put the full load of a clean wheel on it.

In the house units. It’s always one of two things. 1). Low air flow. 2). Low freon. Always. Every time.

Hi! My ac condensator is dripping water only the half bottom of it. Ac still working perfectly, the problem is that if I leave it running for a long time the condensator freezes up and builds up ice and then blocks the air from coming out of the vents... My ac is on a Condominium where cooling towers are used. What can I do to stop the leaking? Thanks in advance!

My ac is down again, but this time it’s not a freezing coil. Filter is recently changed, coils is not freezing, wheel is clean as well. Any other suggestions to check for that don’t involve me buying tools, or supplies? Thanks 🙏🏽

Mine: A contactor on the condenser was stuck closed, causing it to run continuously.

The last ac tech that came to my house to check my ac unit moved the sensing bulb away from where it was so it is not attached to the evaporator exit. Is this ok? You have any idea why he might have done it? Is this harmful to my ac unit? It is about 13 years old but it has been working fine. This is not my regular ac tech. Thank you in advance for your professional opinion. Have a good day.

What about operating heat pump in a/c mode below 60 degrees?

What about units running during low ambient conditions, with no head pressure control? That has caused many evaporator coils to freeze up.

Question, I have told that the ducts need to be replaced to a larger size. I am DIY person. Generally, would increasing the size of the ducts by 2 inches resolve the issues? The system works fine now but I just wanted to get some info about the ducts. Thank you.

1.check air filter first(just like you do with your vehicles) 2.take pic of the evap coil in selfie mode with phone so u can see the bottom (dont drop the phone lol) 3.check blower speed 4.check zone board and the wiring to see how many dampers your dealing with in the home 5.turn off one of the thermostats and keep 1 running and go to attic to inspect dampers and ductwork 6.make sure your dampers are close and open based on which thermostat you turned off and left the other on. 7. Make sure you put your hand on the vents to see if its off on the zone you turned off.. 8. Go get your pressure readings

I loved you comment at 6:44🤣😂

What is your opinion of turning the heat on to thaw the evaporator

Hi, i have a long lasting doubt, cylinders saturated pressure depends on ambient temperature, same way evaporator pressure depends on which temperature, as there is return temperature and supply temperature, what decides suction saturation temperature

Too dense of an air filter? From my experience (I'm not a repair tech, just built super energy effecient homes) is too small of an air return duct! In my homes I filtered at the return grill and at the HVAC unit. Yes I have to oversize my return duct (which cost more to install) and I put multiple return ducts throughout the home! If there's ice beyond that, then it's a mechanical failure. Air flow is very important across the coil.

25 years ago I helped with ac tech in highschool and he'd always complain about people not changing filters or using a high Merv filter. What stuck with me is he always said it's a filter not a purifier

Why is my Mitsubishi split unit leaking water from the condenser when the heat is off it is brand new I install for units all together that’s the only one doing it thank you

Why? Loss of charge or dirty/clogged or lack of airflow

I usually check the static pressure when I rub my shoes on the carpet and touch the customer s earlobe

I had an window unit A/C that use to freeze up tight in the front of the unit. I took it out of the window and bought a new unit.

I just changed my filter bout a month ago, still like new, but coil frozed up bout 3” inch….. 😔🤞🏼🤞🏼

Can't you melt the ice by leaving the unit on fan?

The help blocks the door open during hot lunch period to cool kitchen. 2 pm freeze up.

New Subscriber , Hi Every One , 🇲🇦

This is way above my skills as an apartment maintenance technician lol…but great video though