I think if you consider enthalpy or total heat, it makes more sense. In some areas, humidity is the largest part of the load. You can plot the enthalpy change on a psychometric chart, put in some figures for the airflow, you can actually come up with BTU’s change from supply to return. Sensible heat is only one part of the equation. I’ve seen anywhere from 16 to 26 degrees Delta T which agrees with you’re chart. I think all techs should have a laminated copy of your chart. Great presentation.

Your videos are amazing, I’ve been watching and learning so much and so easily. Very well taught, thank you Eric.

Your lectures are an invaluable learning experience. Thank you

Thanks for the information. See you on the next one.

Thank you so much for all your Times and video.

Great info. I learned a lot. Thank you

Well done Thank you for your sharing

Glad I signed up and rang the bell Señior Shidell! Always look forward to more of your mentoring. Just passed my entrance exam to ARPEC and going for interview in June. Should start apprenticship in August. I will refer my fellow techs to you for sure.

@hvacservicementor

3 жыл бұрын

Best of luck in your interview! Welcome to the channel.

I draw my return air from the basement where it is consistently near 70F all summer at about 55% humidity. I have a thermometer in the air stream just above the A coil and it reads 48-49 degrees when the OAT is 85 or higher. When the OAT falls to the 70s the temp drop increases by about 2 degrees. When it cools off outside at nightfall to 68-70 and the system still runs a couple cycles, I will have 45-46 degrees above the A coil. The whole time the air handler inlet temp and humidity has remained constant. A change in OAT alone will affect temp drop on my system. It is an R-22 2.5 ton fixed orifice.

Hi Eric, this is an incredibly insightful, and valuable video. I live in the deserts of Southern Arizona where humidity is commonly in the teens, and sometimes even less. Is there a chart for these arid conditions?

Hi! Is there something like this but for the heating side of things?

1:42 - TD on the exams refers to the difference between the saturation temperature and the temperature of the media having heat removed. The greater the difference the more heat is moved.

@hvacservicementor

13 күн бұрын

Not sure which exam you are referring to, but I have never seen that on any exams I have personally taken. I can say that it can often be confusing for a lot of people because there isn't really a strict standard of terminology in our industry. Not like medicine for example. There are also regional influences and traditions where in one part of the country people use one term and in another part of the country people use a different term for the same thing. For example, the value that you mentioned is also referred to as approach temperature. This is completely different than the air temperature difference across the evaporator. When we are examining the difference between air in and air out of an evaporator coil, delta T greater than standard for the existing conditions results in less total heat moved in BTU/h. This is extra fun when reading plan drawings from engineers who may be from another region or control points. I know what an RTU is. I know what a CU is. What the heck is an RCU?

Please give chart in Celcius scale also. Thanks

Can you elaborate where the number 400 ft3/min/ton originates? Is it the way AC controllers are programmed? And the overall the logic by which fan and compressor speeds are controlled?

One last tuning for the videos .. when you use "Degree" , please say the unit. Celsius? or the one based on one Horse blood temperature?

@hvacservicementor

8 ай бұрын

Freedom units. Thanks for watching!

For a hotel type AC wall unit if you had a way of cooling the air at the place where it sucks in the warmer air would that alleviate some of the work of the compressor and therefore save on amperage consumed and still cool effectively? Just assume the cost of making that cooler air is free and the thermostat is say 15' away.

@hvacservicementor

3 жыл бұрын

It's never free. However, power consumption in any AC or refrigeration system is directly related to heat removal. If the system has less heat to move, it will consume less energy.

@offgrid2010

3 жыл бұрын

@@hvacservicementor Great. Thank you for your reply. My thinking cap is on. Not for free energy but for lowering the cost from the power company.

Ok

Can you make one on schematics

@hvacservicementor

3 жыл бұрын

Already did... Go to www.hvacservicementor.com and look under the Techflix tab for the Electrical Schematics class. AC Boot Camp has a unit on wiring and schematics too.

@michaelcostello6991

3 жыл бұрын

@@hvacservicementor It would be nice to know the schematics you cover. However im sure this class is well worth it.

SH and SC are irrelevant with mini split systems

SH and SC are irrelevant with mini split systems

@jakem117

3 жыл бұрын

So you're rotary compressor will be happy with 70 degrees, or zero degrees of super-heat? lol These measurements may not be the most valuable for that equipment, but blatantly ignoring them is ignorant

@timrob0420

3 жыл бұрын

@@jakem117 actually ductless systems run at 0 degrees superheat frequently and do so because they have an accumulator directly attached to the compressor to store liquid refrigerant. The only way to truly check charge on these systems is with sensible heat calculation or recovering and weighing charge, unless of course it’s so dead on charge that there is no liquid refrigerant at all and only vapor.

@jakem117

3 жыл бұрын

Listen, if vapor is entering the compressor, and vapor only. There is superheat... Remember how thay works? lol No compressor I know of can pump liquid. Now if your instruments aren't accurate that's a different story.

@UltraHydrophobiccoat

3 жыл бұрын

Unrelated?! Based on the temperatures on both copper lines on mini split system? The temperatures on those copper lines are the same because BOTH lines are suction lines.

@timrob0420

3 жыл бұрын

@@jakem117 I’ll agree that you can measure SH at the compressor suction line, but measuring evaporator superheat is irrelevant, and sub cooling is irrelevant as well when it comes to mini split systems