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.
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!!
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.
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.
I’ve been doing for couple years an all those are normal points of interest to check to my knowledge but fortunately I’m getting to work with the owner of the company who has worked 35 years hisself in HVAC an does that help a bunch to have him on hand
I don't understand the low refrigerant cause. It seems to me that it would make the coil less cold. I would think one cause could be having exterior doors open too much, allowing excessive humidity in.
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.
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.
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.
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.
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.
Pushing the profits they are damaging the industry it’s self. People used to repair refrigerators and freezers but the cost of repairs kept going up until most just went to the dump. Now you can go to the store and see the ultimate product of this. New chest freezers use cyclopentane. No more Freon. They are apparently designed to go to the dump. You can’t get the work back even if you tried.
Well you wouldn’t have to do a diagnostic on a standard inspection which most companies slot 2 hours for, if it becomes a service call that needs more time, for my company, I just let me dispatch know, they will give me all the time I need to complete a call correctly.
@@David0lyle I agree!! It started when all the big American manufacturers sent there product to china for large profits. My Rheem is 22 years old and I am dreading the day I will have to replace it with a chinese replica .
U dunno how to check a dirty filter? A bad fan motor and/or a capacitor is also very easy to swap out too. Basically, the only thing u couldnt do with the slightest amount of effort, is the last part: the refrigerant.
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.
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.
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 !
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.
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!! 🤘🤘🇺🇸🇺🇸
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.
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?
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.
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.
So, I get what might cause an evaporator coil to freeze, but I'm trying to understand how it happens. An example, if my coil is dirty, the evaporator will freeze because the refrigerants drop in temp. Is causing that (due to no heat absorption) am I in the right ball park here?
@@Maxumized yeah took me a while but I finally get it. Pressure and temp are related. Restricted air flow means more liquid refrigerant which means less pressure in the Evap. Which in turn leads to lower temp. I never knew hvac could be so engaging
The way I see it, low air flow/dirty condenser coil has the same effect, that is, limiting air flow across the evaporator coils. This causes the air to slow too much/spending too much time around the evaporator coil and thus loosing too much heat to the coil. To the point that this air has enough heat sucked out of it that it gets below freezing! And on and on it goes...more frost more air flow restriction means even more frost...I know there’s a word for this...maybe reinforcing feedback loop. You see, the refrigerant going into the evaporator is all gonna go from liquid to vapor regardless of what the air flow is doing...so the refrigerant must suck whatever heat is can from the air...it’s an intrinsic property of phase transformation when liquid is transforming into gas. Prove me wrong but this gotta be it!
@@Brasil28 you’re sorta right. Let me use your example, a case where my evaporator coil is extremely dirty. All that dirt and gunk will definitely restrict my airflow across that Evap. But, frost won’t accumulate because the air was moving too slow and lost all of its heat, frost accumulates because of the moisture that’s in the air condenses and freezes when it passes through the evap coil. See, when you have a major air restriction, your superheat will be very low, meaning you’re not absorbing *enough* heat from the air (because of the dirty coil causing the restriction) and because you now have less vapor than usual, pressure inside your evap, will be lower than usual. And as we know temperature and pressure are related, a low evap pressure = low evap, temp. This low temp in the evap is what causes the moisture in the air to freeze as it passes through the coils. I hope I explained that well enough.
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.
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 🙏🏽
I'm not an HVAC tech at all, but deal with Magic Paks. (All in one unit within the rental unit.) I turn the system off and turn the fan to "on." Make sure your condensation drain is clear, tho. Our 3/4" drain lines start on the 3rd floor and lead to the garage that tends to get plugged also.
i always give my customers this disclaimer before I clean a blower wheel. also if the evap coil does freeze up i tell them that expanding ice can cause leaks in the joints of the coil. I've witnessed a 1 year old split system (in the attic of a 30 unit apartment building heating and cooling all the common areas) whos filter never been changed (one year) have leaks after i thawed the thing. i'd already put in my 2 weeks at this point so i no longer had a filter when talking to customers and told them since you were cheap and didn't want us to maintenance the equipment, now you have a massive leak.
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?
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.
(Not an expert) I would increase the duct size if that has been recommended. For example, if the ducts are 8 inches and you are going to 10 inches, the cross-section increases 50%. If going from 6 to 8 inches the cross-section increases 78%. Since the goal is to get above the point where the evaporator freezes that could be a crucial difference.
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
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!
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.
I also live in Colorado (Denver) I work on mobile home a lot. I se these problem so many times 99% of the time is the dirty coil or low on refrigerant, also most of the times mobile homes don't have TXV and have smaller evap coil with larger capacity C.U.
All of these videos leave out the most important thing. How does a homeowner or tenant check! If the evaporator coil is frozen is this even practical for me to check or is this whole video superfluous because I need to call AC technician anyway
@@Maxumized which part did you miss? Did you not even watch the video? It's you that don't understand. I've been doing HVAC repair for 35 plus years. Refrigeration and auto ac for 43 years..
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.
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
I know this is off topic but, i just installed a unit at my school that i got from AHRI after being tested. in 16 years i have never seen 110v on condenser contactor coil. checked prim and secondary side of xfrm, 120 prime 28 secondary. Followed to the board same volts. some how i'm getting 110v on my contactor coil at my condenser. Has any one seen this before.
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
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.
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.
I know the refrigeration cycle but I can't visualize why low refrigerant would cause the evaporator coils to freeze. Can someone please explain it to me? Thanks in advance.
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??
Oh and another thought, these damn smartphones today, nobody gets anything done anymore everywhere I go people at any job f in with their gdamn phone. It's absolutely insane.
Million dollar question can running the AC with the evaporator frozen cause the lost of refrigerant ? And is that consider a leak created by running the AC while evaporator is frozen??
Why would the low charge still freeze up with proper air moving over evap coil, the delta T drops? With low charge there would be no liquid in evap only low pressure vapor, always seems strange coil would freeze up to me.
Because unless the system is flat there is still some boiling refrigerant at the start of the coil but at a lower pressure and temperature. The ice can begin there and then cascade through the coil as the ice restricts airflow.
This was a very good video
Crispy clear explanation; This information is worth $$$
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.
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!!
Not only did I learn a lot, but I realized how much I _still need to learn._ 10/10 it hurts
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.
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.
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.
I’ve been doing for couple years an all those are normal points of interest to check to my knowledge but fortunately I’m getting to work with the owner of the company who has worked 35 years hisself in HVAC an does that help a bunch to have him on hand
It was low charge for me both times.
I don't understand the low refrigerant cause. It seems to me that it would make the coil less cold.
I would think one cause could be having exterior doors open too much, allowing excessive humidity in.
You forgot stuck closed Expansion Valve
@@qua7771 TEV wide open because short on refrigerant and then flooding evaporator?
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.
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.
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.
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.
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.
Bingo, and thats why we were told we needed a 6k$ new unit, when the problem was a dirty condenser.
Pushing the profits they are damaging the industry it’s self. People used to repair refrigerators and freezers but the cost of repairs kept going up until most just went to the dump. Now you can go to the store and see the ultimate product of this. New chest freezers use cyclopentane. No more Freon. They are apparently designed to go to the dump. You can’t get the work back even if you tried.
Well you wouldn’t have to do a diagnostic on a standard inspection which most companies slot 2 hours for, if it becomes a service call that needs more time, for my company, I just let me dispatch know, they will give me all the time I need to complete a call correctly.
@@David0lyle I agree!! It started when all the big American manufacturers sent there product to china for large profits. My Rheem is 22 years old and I am dreading the day I will have to replace it with a chinese replica .
@@vikingson9000 Ain't that the damn truth. I just serviced a system installed in 1981. That thing ran like a champ.
This video is very descriptive but way above my technical knowledge. I'm going to just call my local HVAC repair guy.
U dunno how to check a dirty filter? A bad fan motor and/or a capacitor is also very easy to swap out too. Basically, the only thing u couldnt do with the slightest amount of effort, is the last part: the refrigerant.
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.
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.
can you make a video taking about how to identify improper components sizing in refrigeration system
As a new tech some these comments help aswell
As always, his videos are the best.
I'm very grateful all the effort you put into these videos.
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.
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 !
I have used head pressure control to successfully stop ice.
(Orface no txv)
24x7 server room acs. Florida does not get cold enough to
Great video, now let's touch on limit switches tripping!
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.
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!! 🤘🤘🇺🇸🇺🇸
I like this video. The speed and content is amazing.
Great video. Another thing to check is the evaporator blower motor. Is it seized? Does it get power? Bad Transformer?
It's an indoor fan on a split furnace/ac unit, not an evaporator fan.
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.
Great video like always thank you for sharing your experience with all of us 👍🏻🍺
Mine: A contactor on the condenser was stuck closed, causing it to run continuously.
Thank you! I like to start with airflow, and a lot of people who have more 'experience' always jump to an under charged unit
Yup, I needed a lot of pictures to watch this vid. But seriously, it is a very good vid.
Always informative and interesting to watch. Another great video. Thank you.
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?
God bless you for this good film
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.
Excellent information. Always learning something.
Always great video. This one was chilling
Subscribed, great info. Clear, to the point. Great job!
Amazing, well organized presentation, clear explanation.
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.
How isnt that related? Bad airflow, same as a plugged air filter.
So, I get what might cause an evaporator coil to freeze, but I'm trying to understand how it happens. An example, if my coil is dirty, the evaporator will freeze because the refrigerants drop in temp. Is causing that (due to no heat absorption) am I in the right ball park here?
Yes! You got it. On a dirty coil, the refrigerant temp drop is accelerated so coil continues to drop in temp and moisture in air freezes.
@@Maxumized yeah took me a while but I finally get it. Pressure and temp are related. Restricted air flow means more liquid refrigerant which means less pressure in the Evap. Which in turn leads to lower temp. I never knew hvac could be so engaging
The way I see it, low air flow/dirty condenser coil has the same effect, that is, limiting air flow across the evaporator coils. This causes the air to slow too much/spending too much time around the evaporator coil and thus loosing too much heat to the coil. To the point that this air has enough heat sucked out of it that it gets below freezing! And on and on it goes...more frost more air flow restriction means even more frost...I know there’s a word for this...maybe reinforcing feedback loop.
You see, the refrigerant going into the evaporator is all gonna go from liquid to vapor regardless of what the air flow is doing...so the refrigerant must suck whatever heat is can from the air...it’s an intrinsic property of phase transformation when liquid is transforming into gas.
Prove me wrong but this gotta be it!
@@Brasil28 you’re sorta right. Let me use your example, a case where my evaporator coil is extremely dirty. All that dirt and gunk will definitely restrict my airflow across that Evap. But, frost won’t accumulate because the air was moving too slow and lost all of its heat, frost accumulates because of the moisture that’s in the air condenses and freezes when it passes through the evap coil. See, when you have a major air restriction, your superheat will be very low, meaning you’re not absorbing *enough* heat from the air (because of the dirty coil causing the restriction) and because you now have less vapor than usual, pressure inside your evap, will be lower than usual. And as we know temperature and pressure are related, a low evap pressure = low evap, temp. This low temp in the evap is what causes the moisture in the air to freeze as it passes through the coils. I hope I explained that well enough.
You sound intelligent and spout intelligence. Intelligent video. Thank you!
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.
this channel Kicks ASS!!!
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 🙏🏽
Excellent video a bit of rush but has the correct information, Thanks
My favorite channel
What is your opinion of turning the heat on to thaw the evaporator
I do it quite often but monitor the liquid line temperature
I'm not an HVAC tech at all, but deal with Magic Paks. (All in one unit within the rental unit.) I turn the system off and turn the fan to "on." Make sure your condensation drain is clear, tho. Our 3/4" drain lines start on the 3rd floor and lead to the garage that tends to get plugged also.
Can't you melt the ice by leaving the unit on fan?
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.
i always give my customers this disclaimer before I clean a blower wheel. also if the evap coil does freeze up i tell them that expanding ice can cause leaks in the joints of the coil. I've witnessed a 1 year old split system (in the attic of a 30 unit apartment building heating and cooling all the common areas) whos filter never been changed (one year) have leaks after i thawed the thing. i'd already put in my 2 weeks at this point so i no longer had a filter when talking to customers and told them since you were cheap and didn't want us to maintenance the equipment, now you have a massive leak.
Just flip into heat thawed in minutes just make sure condensate isn’t clogged or you’ll flood the evap..........
What about units running during low ambient conditions, with no head pressure control? That has caused many evaporator coils to freeze up.
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?
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.
(Not an expert) I would increase the duct size if that has been recommended. For example, if the ducts are 8 inches and you are going to 10 inches, the cross-section increases 50%. If going from 6 to 8 inches the cross-section increases 78%. Since the goal is to get above the point where the evaporator freezes that could be a crucial difference.
Great video
I would like to see videos on mini split systems
I’m confused. @1:51 you say I could use a heat gun but then @1:57 you say don’t use extreme heat. Doesn’t a heat gun produce extreme heat?
Not if you don’t get too close. Better off using a hair dryer on high. 1700 watts is a lot of heat and there is plenty of flow.
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
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!
Good commonsense information, thanks.
Thanks from Bangladesh.
Thanks Bryan!
Very Nice information good to see!
Why? Loss of charge or dirty/clogged or lack of airflow
Air flow is always good to check out
What about operating heat pump in a/c mode below 60 degrees?
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.
I also live in Colorado (Denver) I work on mobile home a lot. I se these problem so many times 99% of the time is the dirty coil or low on refrigerant, also most of the times mobile homes don't have TXV and have smaller evap coil with larger capacity C.U.
All of these videos leave out the most important thing. How does a homeowner or tenant check! If the evaporator coil is frozen is this even practical for me to check or is this whole video superfluous because I need to call AC technician anyway
In the house units. It’s always one of two things. 1). Low air flow. 2). Low freon. Always. Every time.
B
You just stated a generalization that is always true of every system...so, did you not understand this video?
@@Maxumized which part did you miss? Did you not even watch the video? It's you that don't understand. I've been doing HVAC repair for 35 plus years. Refrigeration and auto ac for 43 years..
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.
Great info. Tips. Thanks Bryan.
Great job and video like always
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
Very good presentation.
Great tips Bryan.
I know this is off topic but, i just installed a unit at my school that i got from AHRI after being tested. in 16 years i have never seen 110v on condenser contactor coil. checked prim and secondary side of xfrm, 120 prime 28 secondary. Followed to the board same volts. some how i'm getting 110v on my contactor coil at my condenser. Has any one seen this before.
Nope, but you got my curiosity. Let me know what you find.
Are you measuring across the contactor coil direct or are you measuring from chassis ground then to one side at a time on the contactor coil?
If you’re getting 110 to a 28 volt coil - it should burn up fast ?
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
Well, it is a filter, that's the proper name for it, 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
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.
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.
I know the refrigeration cycle but I can't visualize why low refrigerant would cause the evaporator coils to freeze. Can someone please explain it to me? Thanks in advance.
Thank you for the info
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??
Guess he figured his picture was worth $15.56. At least you got reimbursed. No telling how many times he has stolen people's money.
Oh and another thought, these damn smartphones today, nobody gets anything done anymore everywhere I go people at any job f in with their gdamn phone. It's absolutely insane.
Thanks you're the best.
Million dollar question can running the AC with the evaporator frozen cause the lost of refrigerant ? And is that consider a leak created by running the AC while evaporator is frozen??
@@timusa3937 I was able to add a few pounds and working good now but wondering if that amount indicates I have very bad leak??
@@timusa3937 but could the Freon leak then stop leaking because it’s work great better than every
@@timusa3937 should the dollar stick to any return or main return
Great video
I just changed my filter bout a month ago, still like new, but coil frozed up bout 3” inch….. 😔🤞🏼🤞🏼
Why would the low charge still freeze up with proper air moving over evap coil, the delta T drops? With low charge there would be no liquid in evap only low pressure vapor, always seems strange coil would freeze up to me.
Because unless the system is flat there is still some boiling refrigerant at the start of the coil but at a lower pressure and temperature. The ice can begin there and then cascade through the coil as the ice restricts airflow.
Thanks for sharing your knowledge
Great video. Thanks so much for sharing!
Thanks for sharing
It’s all about the airflow.
Great 👍 job explaining.Thank you
The help blocks the door open during hot lunch period to cool kitchen. 2 pm freeze up.
Muchas gracias por enseñar
Is 40 degree drop from my vent temp inside to 110 outside optimal at 76 inside vent
If my math is correct, wouldn't that be a 34 degree temp. difference, not "40" point difference?
Enjoy your videos Great job😜
Good job.
What about an inside fan? If it wasn't pushing enough air. Let's say you hard wired heat and cooling to be on medium speed.
Very helpful video. Thank you : )