Symptoms of Low Evaporator Airflow

Next in the series based on HVAC Refrigerant Diagnostic Quick Sheet Bryan talks Symptoms of Low Evaporator Airflow.
Videos on Airflow from our friends at Tru Tech Tools channel:
• Air Flow Measurement P...
• Air Flow Measurement P...
• Air Flow Measurement P...
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www.hvacrschool.com/5-pillars
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[@Bobherry]

Sup. I am a Residential/Commercial student. I started back in Jan 2020 and graduate April 2021.

[@TheGhettoLobster]

Yooo Greg come back to the HVAC discord

[@Bobherry]

@@TheGhettoLobster id love to but I dont have a invite

[@rickbraden4272]

Excellent. Thank you. Just ran into this on a change out yesterday.

[@jredbokie1247]

You guys have helped me soooo much thank you for all you do.

[@Automotive_Solutions]

Thanks for the explanation. I'll be checking out more of your videos. 👍

[@alimayah4461]

Hello, thank you for your useful and valuable teachings. If possible, it would be better if the movies have English subtitles, thanks

[@AlexGarcia-vv4ux]

Just seen your company’s reviews online incredible amount of positive comments 300+ . I also saw your job hire requirements and benefits you guys have a great company and great KZbin channel 👍🏼

[@HVACS]

Thanks!

[@j.r.1223]

Sweet. Greatl video! Thanks

[@timrob0420]

You should do some of these on a heat pump in HEAT mode, that would be freaking awesome

[@josetrevino9869]

These are good, they help you touch base, strengthens your foundation

[@johnd4348]

I have a high calibrated hand for measuring line temperatures.

[@DanBurgaud]

As I was cleaning our window type AC unit I noticed it uses 2 capillary tubes as expansion valves going to multiple copper loops in the evaporator. Why not have a single (but long) copper loop? So I took an IR thermometer and measured some of the temps in the evaporator: Return Line (going back to the accumulator): ~ 26c cooper loop: ~ as low as 8c, to as high as 25c unfortunately, I could not measure the temperature on the capillary tubes. Care to make some comments? Thanks!

[@hvacplayer3238]

Dude you’re the best.

[@jakej81]

How accurate is mq measured airflow with hygrometers? Could this method be used in heat pump heating mode?

[@efco24]

I have a question. How far from the evaporator does your temperature probe need to be?

[@josetrevino9869]

On another note how do you feel about testos 417 vanr anemometer for measuring airflow

[@MrGarcon98]

with all this usefull info , it reminds me of my teacher alsmost at the beginning of the hvac course ,,,he said air conditionning is not a 100% corrrect science ! and anything within 3 degrees is acceptable in hvac . just saying ,,,,thanks for the info

[@koundridinesh5494]

Could you please explain ammonia chiller (-15) Why section presser is going to -18.9

[@alexzapata692]

Awesome 👍🏽🔥

[@sergiomansilla]

Good video !!!! Saludos

[@vnesmuonnam]

Love all your videos. If you speak little bit slower that will help a lot of new techs. Thank you.

[@troymason4799]

I had 78 return, 52 suction saturation and 5 superheat on a piston. Humidity within range (68wb). 435psig on high side, 18 td in a commercial place that wasnt cooling.

[@hiseminencetheholymacdiarmada]

435 psig is awfully high. What system are we talking about here?

[@forzamilan07]

Need some more info... sc? Supply?

[@ronniebuchanan6575]

Sounds like a TXV valve problem.

[@rickcantu4501]

Great video as usual! Could u make a video on nitrogen pressure testing. Sometimes when I do mine with my resto 557 I do pressure test for 20 min and I see it drop like .4 sometimes .7 , is that acceptable? Could it be an actual leak in system or in my hoses ? I bubble test my hoses and find no leaks. I hate having those doubts Though. But then I pull vacuum to below 500 and decay tests passes

[@chinoballa760]

That’s totally normal. Sometimes your pressure will go up too if the sun is hitting the unit because with higher temperatures goes higher pressures

[@SJ-xk5zm]

Sir I am from India new cold room cr22k6m compressor starting 35 amps internal trip after 3min starting ok capacitor relay new but same problem please help

[@cpaul57]

How about hydronic forced hot air. The heating coil on the supply is so restrictive

[@publicmail2]

I have a 3 ton heat pump my SP are excellent spec is .5 low tap I have .26 so I'm moving a lot of CFM. From the manufacture chart of blower low tap is 1040cfm, med 1302, high 1504 and verified these very close with hood. On high delta is 17 F, med 18.5, low 19.8. humidity is 40% so I wonder what blower speed is best for efficiency. I think the high is moving too much and a little loud on supply, what do you think? I think you can be moving too much air hurting heat removal and humidity capture. I even rigged a wifi switch thru a relay to switch fan speeds remotely on a PSC motor.

[@robertcherry4971]

Medium speed is what you want especially for cooling.

[@coldfinger459sub0]

I just sent this video to a automotive technician in the UK trying to explain airflow problem over evaporator giving you false readings that you cannot trust on your gauges. I hope he comments and replies when he sees this video. HVAC and automotive side gets very little attention and very little education. They need our help.

[@honestman276]

Compact symptoms chart (such as suction and discharged pressures, superheat, subcool, ampere rating, and delta temperature against each indicator or fault. Thanks from Bangladesh.

[@rosemariejarrett3378]

Good evening can I use a 12000 btu evaporator coil I got from a 410a system with a r22 condenser also 12000 btu

[@rosemariejarrett3378]

Both from mini split ACs

[@gamewizardks]

Will an undersized Evap also cause a low superheat/low suction situation? I'm currently working on a system that is mismatched. The condensing unit is 2 tons and the evap is 1.5 tons. It's an R-22 system and I cannot get the suction pressure above 55 no matter how much refrigerant I add. I am checking superheat and that's why I stopped adding refrigerant, because SH got too low.

[@MegaDysart]

I know this an old comment but I wish there was a clear answer to this. In my mind, an undersized evap would cause high superheat because the mass flow rate would be lower due to the size. However I'm not sure that's a 100% guarantee because an undersized evaporator might be the cause of low airflow, which could have the opposite effect. Did you ever get this figured out?

[@gamewizardks]

@@MegaDysart Turns out, in the end, there was a restriction in the coil and it was replaced with a properly sized coil. This system worked perfectly after that. Thanks for the belated response. Cheers!

[@cu27rotary70]

I went on a call for frozen coil and found five registers closed. One of the boys gets too cold and closes them.

[@raidone7413]

I bet the door is shut when he closes them. Less household airflow. I wonder if an ecm motor will have the same problem

[@PhilipAlonzo]

Question anyone why is my fan not going on when i put the thermostat on on or even auto still no air out vents

[@dougsanders6034]

Have your capacitor checked.

[@hewaakrey8581]

When we use pt chart how we can calculate temperature 🌡 for ac ,coling and freezing How to know what temperature will be to choose pressure of section line

[@caru3257]

in an install, you use the manufacturers guide. in a service call without the manufacturers info, use superheat for fixed orifice and subcool for txv.

[@jagsjer]

I went on a call the other day. She stated she had three companies out and they said everything looks fine. She said I can’t get the house down below 80° on a 100° day. Gauged up to system with smart probes and saw the Subcool was at 11° as stated on the tag. But say suction temp up and delta t only at 12°. Mins you it’s a down flow application. Filter clean evap was clean as I. Was looking at evap I found that the installers had made a wood frame between the coil and furnace. And it only had 3” of a gap on each side of the coil. ADP coil that had about ten inches of flat space on top and the air would dead head there and only 3” on each side where air would maybe get threw the coil. All in all poor install lead to this lady having issues for the last four years.

[@hookedup9424]

Good morning,I have a question HVAC SCHOOL. What causes no sweat on suction line

[@MegaDysart]

When the suction line is sweating it is because it is colder than dewpoint and water in the air condenses onto it. Therefore if the suction line is not sweating then the suction line temp is not at or below dewpoint. Not necessarily an indication of a problem, you'd need to evaluate the rest of the system and ambient conditions to determine if there is an issue

[@smacleod69]

I bought a testo hot wired anemeter. And it sucks on flex and box systems where you have a 4ft plenum on either supply or return with multiple flex sizes attached to it. For example. I have a supply plenum inside dimensions 15x17 and Im looking for 800 cfm and measuerment might be close. Then I will then input dimensions 10x10 for 400 cfm. Stick the probe in the same 15x17 plenum and will read 350 cfm. That probe is not an accurate way to measure cfm!

[@majid8636]

What are the reasons why the evaporator is half cold, while the other half is a little cold?

[@IALewis]

👍🏿

[@samuelg3586]

Man I wish we actually had enough time to test these things on service calls. That's the biggest problem

[@eduardoguardado6999]

Amen

[@buddyholly8999]

I would suggest not taking out all of the parts of the videos when you aren't talking. It's too fast to interpret when there are no pauses.

[@abdulhvac2395]

Man you are very fast .Would you slow down a little bit And make it simpler for a new guy like me

[@EricTurock]

His speed is perfect, in my opinion of course. You could try using KZbin's built-in playback speed control to slow it down.