You are awesome.. very clear and good explanation. Thank u

Professor, you are of a great help for many techs out on the field. Your master classes will make me a real technician. Thank you so much.

@dario6749

Жыл бұрын

Could it happened that you have low subcooling, let's say 4 degrees and your target is 10, and yet your superheat is where it should be. I've been having this problem these last weeks. My theory is that is low in refrigerant but it has just enough to feed the evaporator. My supervisor thinks is because outdoor temperature at which I'm taking my readings, I don't think so it's been mostly between 65-78 degrees. What do you think? Thank you very much for your videos

@love2hvac

Жыл бұрын

Dario, you are correct. The TXV needs a full column of liquid to maintain superheat. If the TXV has even 1 of subcooling it can maintain superheat. But as the house warms up the TXV will open to allow more refrigerant. At that point it will let more refrigerant into the evaporator but it won't have enough coming into the TXV. It will no longer be able to Handel the load that is needed. You supervisor is partly correct but for the same reason. With a low outdoor temperature there is no load so the TXV will only open a small amount so the system still works. But what will happen with it become hot and the system needs full capacity, then we will not have enough Subcooled liquid refrigerant supplying the metering device. The metering device will open but it won't have the refrigerant needed to do the job. This was a great question. I can see that you are thinking about things and I love that!

Amazing learning alot with your videos it’s actually clicking in my head. Thanks alot

Thanks from Bangladesh.

Just seen your video with HVAC 2.0 👍 That was one of the best series of TXV and piston videos with the explanation of superheat and sub cooling I’ve seen a decade saved as favorites file.

Brilliant video, thank you.

@love2hvac

Жыл бұрын

Thank You!

Yet another well explained and easy to understand video from you Ty!!!! Your teaching skills are 👌👌, Keep the videos coming bud 👍

I like these scenario diagnostics

Great video brother 💯💯💯💯💯

This video helped have an hvac revelation of trying to understand and remember how to troubleshoot subcool and superheat 😂 finally thanks your teaching skills are much appreciated 👍

Great information. One of my 1st service calls last year was a txv completely shut down. This video would have help. I was by myself n thought it was solenoid valve was down. But my boss came later n we changed the txv. Thanks ty.

4:18 - Thanks for including FOREIGN objects on your Restriction slide.

YOU ARE A BLESSING TO THE WORLD

Hey sir I am slow learner but ones I get it is there for me . Thank you for breaking down . Please make video on low voltage problem in future. 👍🏼

Phenomenal video thank you for sharing

Been awhile since yah posted, I see you are collaborating with some other awesome HVAC guys. Hope you’re all good Ty.! Btw I got some of that insulation tape you suggested. Awesome stuff

@love2hvac

3 жыл бұрын

Thanks Sam, I have a bunch of recorded material, I'm just behind on editing. I'm working with 2 companies in NYC for some custom on tue job training. I should be back on track soon.

@amersingh2557

3 жыл бұрын

Thanks for the update. looking forward to see some more content. Be cool 😎.

I'm finding it useful to put "liquid" in front of "starved" and "flooded". It's just more precise and keeps me from confusing myself.

Thanks Prof. for this great lecture. Something I am still trying to understand is why in TXV systems, when the charge is low, the subcool drops but the TXV maintains the superheat. If the TXV is allowing in more refrigerant to maintain the superheat, why isn't the subcool maintained as well

@love2hvac

3 жыл бұрын

At a steady load as long as the TXV has at least a solid column of refrigerant it will maintain superheat. Even 1F of subcooling (a low charge) the txv will do it's job. However once the load increases and the txv opens it will no longer have enough refrigerant (subcooling) available for the TXV to fill the evaporator. When the manufacture asked for ____°F subcooling is is so the TXV will have enough refrigerant through a variety of conditions.

Excellent thanks

Your. The best

Best video

I actually removed my TXV sensing bulb from the suction line to see what effect it had on temperatures. I wanted to see if TXV was working at all. 10 SC, 20 Total SH with bulb mounted. Removed bulb from suction line (which should open and allow more liquid into evap) and 7 SC, 4 TSH. Both went down as described @6:35. After I reattached it to the suction line, it hunted for a bit. The evap temp dropped to 30 but then it started to steady rise back to normal.

@love2hvac

9 ай бұрын

The job of the TXV is to maintain a constant level of superheat. By doing so we also know whe have the correct amount of liquid in the evaporator changing state (saturation) Actual suction line temp ___⁰F Minus Suction saturated ______⁰F = Superheated vapor_______⁰F When you remove the sensing bulb it does not know the actual suction line temperature, it reads the warmer air temperature. The TXV thinks the superheat is too high so it open the valve to let more liquid into the evaporator. By having more liquid the amount of superheat drops and that's why your SH value drops.

Awesome video. How does outdoor ambient temp affect the refrigeration cycle? I've been trying to diagnose my 5 ton R410 heat pump system (SEER 14) and have tried different filters, different blower settings and bulb placement in order to maximize cooling during hot summer days in Southwest. Example: 100 degrees outdoor. Cond temp 122, LL 112 = 10 SC (name plate calls for 10...perfect). Evap temp 46, SL@cond 66 = 20 Total SH. Return 79, Supply 56 = 23 DT. Is 20 Total SH too high or appropriate for hot dry climates? Another example when it was 111 outdoor. Cond temp 136, LL 118 = 18 SC (high). Evap 46, SL 72 = 26 Total SH (high).

@love2hvac

9 ай бұрын

The conditions do affect the system operation. The farther apart the indoor and outdoor temperatures are, the higher the compression ratio becomes and the lower the performance the system will have. I don't know how many CFM of airflow you have or if the unit is installed in an attic, closet, garage or basement, or how long the refrigerant lines are. It looks like there may be a minor issue since the SC and SH both climb when it's 118. My first thought is a restriction. Checking the temperature difference across the filter drier, or see if the TXV is adjustable.

I just want to understand this properly. Does heat transfer in the evap only occur with vapor, not liquid and not saturation? When the bulb is warm due to high superheat, it opens the TXV to allow more liquid to enter (reducing the vapor volume) in order to reduce the superheat by reducing heat transfer? If the bulb is cold due to reduced superheat, it closes reducing the amount of liquid entering, therefore increasing the volume of vapor which allows more heat transfer and increases superheat. Is this correct? It just seems counterintuitive to what you would normally think about the TXV opening and closing. Isn't high superheat a good thing because it means the system is doing a good job of removing heat from the indoor air during cooling?

@love2hvac

9 ай бұрын

Heat transfer is taking place across the whole evaporator but there will be hundreds time more heat transfer in the latent heat of refrigerant boiling vs the sensible superheated vapor. There is more heat absorbed by the refrigerant changing state from a liquid to a vapor (saturation/boiling/latent) than there is by the sensible superheated vapor alone. Because the saturated boiling liquid is at latent heat, it is the same temperature if there is 1% liquid or 99% liquid, but after all the liquid is converted to a vapor, then the temperature will rise. We can measure the temperature difference between saturated conversion point and the actual temperature of the vapor in the suction line. By knowing how much vapor we know how much of the coil is boiling with liquid (saturation) If we don't have enough superheated vapor, the coil is overfilled with saturated liquid mixture and we damage the compressor. If the superheated vapor is too high, there is not enough saturated liquid mixture changing state to cool the air or the compressor.

is it ok to have 13.5 subcooling on a 10 +- 2 Target? per manufacturer? Only slightly higher amps? Will it perform better in heatpump by having more freon? in the winder when the volume goes down due to the cold?

@love2hvac

Жыл бұрын

With straight AC you wont have much issue but for a heat pump its tighter tolerance. In HP mode it needs less refrigerant. some manufactures even use charge compensators to hold the extra refrigerant during HP mode. So over charring a heat pump may work okay in the summer it could certainly be an issue in the winter. I have many times seen high pressure trips from it. Will it affect that system, idk but I recommend staying within manufactures specifications.

@iancunicolae2626

Жыл бұрын

@@love2hvac I thought the charge compensators is to hold extra freon for the winter when the volume of Freon goes down because of the cold. I thought the compensator adds extra freon in HP mode, are you saying its the other way around? that seems so strange!

@love2hvac

Жыл бұрын

@@iancunicolae2626 HP mode needs less Refrigerant in heating mode. Several reasons. #1 look at the size of the outdoor coil and the indoor coil. In cooling mode the liquid Refrigerant is Subcooled in the lower few rows of the condensor. In Heat mode there are not any extra subcooling rows in the inside coil. The coil is too small. #2 The head pressure is much higher in HP mode to get the liquid saturated temperature higher than the air in the house and warm enough to not feel like cool air. The extra pressure reduces capacity. #3 The outdoor temperature is much lower so it's more difficult to boil all the Refrigerant to a vapor. Even with the larger space the Refrigerant has to flow, it needs every bit of it. #4 the lower outdoor temperature also effects the compression ratio reducing capacity. #5 because of the risk of flooding the outdoor coil from not boiling all the Refrigerant to a vapor, an accumulator is typically installed to protect the compressor from excess liquid Refrigerant. A charge compensator allows that excess Refrigerant to be stored in heat pump mode and still be available or pushed in the system in ac mode.

@iancunicolae2626

Жыл бұрын

@@love2hvac Thank you; so my spec says 10 plus minus 2; if I am at close to 14 that's 4 degree of extra subcooling. where should i drop to ? 10? right don't keep it at 11 or 9?

Hi, my r410a with txv unit. The suction saturation temp is about 33F and suction line temp is 48F giving 15F of superheat. But why is my liquid line saturation temp is 97 and my liquid line temp is also 97. I tried adding some refrigerant but nothing changes. This is a high velocity system air handler with a slab coil. I think my suction saturation temp is also too low. Both coils are clean and txv valve is new. Any help would be greatly appreciated. Thanks

@love2hvac

2 жыл бұрын

Sounds like you need to add ref to get the subcooling up.

@mark.r8900

2 жыл бұрын

Ok thanks

@mark.r8900

2 жыл бұрын

Would adding more r410a to bring the subcooling up also raises the suction line temp and suction saturation temp? Thank you for your help sir.

@love2hvac

2 жыл бұрын

If there is enough airflow and if the TXV is working properly the superheat will stay in range even though the temperatures change.

@mark.r8900

2 жыл бұрын

Great. Thanks

How many pounds/tons of refrigerant do you guys think was "vented" into the atmosphere when the Surfside building collapse happened, and then when they raised the rest of the building in Florida on Sunday? 136 residences x 30 lbs ? of refrigerant = 3960 lbs??? + long runs of line to the lower floors and refrigeration units for offices and other offices in the building. Twice as much?? What do you think? Will the people responsible get fined or jail time from the Government?

@love2hvac

3 жыл бұрын

We would also have to categorize that by ozone-depleting refrigerants such as R22 and non-ozone-depleting such as R410A Considering it's oceanside those condensers don't last long over 10 years without a special coating. I would guess that most of the units were 410A or some other nonozone-depleting refrigerant. But they are still considered "global warming". Typically the Florida condos used cooling towers and water source units saving roof space. Since condensers were hanging off the roof there were split systems but I can't imagine there would be enough roof space to hold 342 units plus lobby hallway and elevator units. Running refrigerant lines up 12 stories x 9 feet would be 108 feet vertical rise for the lower floors. That would be a lot of traps and efficiency loss. Nobody will be charged for the refrigerant loss even of the deliberate falling of the remaining building. The danger posed to rescue workers and loss of life already high will outweigh all that.

How to test sensing bulb for TXV Mr. Ty?🌸

@love2hvac

2 жыл бұрын

When I get to diagnostics I will cover that. But simple way is hold the sensing bulb in your hand and the superheat should drop. Put the sensing bulb in a cup of ice water and the superheat should rise on a running system. If it dose not change it's a bad bulb

You, Craig, and Brian rule! Mr. Branaman, I never found your link to the wet and dry bulb temperature chart that you created, in regards to finding the super heated vapor temperature. Would you please be so kind as to sending me the link? Much obliged.

@love2hvac

9 ай бұрын

www.love2hvac.com/supporting-documents

@JasonKurtz-iv5yl

9 ай бұрын

Thank you. I'm grateful for your help.

Sir what if our superheat is high and our subcooling meets target?

@love2hvac

2 жыл бұрын

If it's TXV, confirm airflow first, then adjust the TXV. If it's fixed metering device, find RA wet Bulb out door dry bulb to identify target sh and charge untill meets target. If the subcooling is abnormally high, then look for a restriction.

If you have low superheat, why would you have low subcool? If you flood the evap, why doesn't that extra refrigerant make it to the condenser to over subcool?

@love2hvac

2 жыл бұрын

Low superheated vapor = flooded evaporator, low subcooled liquid = starved condenser. It means there is a problem with the metering device. It's not restricting/ restricting the flow properly. The refrigerator is draining out of the condensor and overfilling the evaporator. The extra refrigerant is stuck in the evaporator, the suction line and the compressor causing damage. The liquid cannot be pumped so it doesn't get pumped into the condenser. Try to pump a liquid and the valor pump valves will break.

Why do people insist in adding refrigerant to all frozen equipment? I just got a no cooling today with four registers closed and a bad T-stat.

@love2hvac

3 жыл бұрын

It's the magic unicorn juice that makes manic cold air. Air flow airflow airflow should be first before chsrging. Idk, I feel your pain.

The kink's

Please slow down when speaking

@love2hvac

Ай бұрын

This IS me slowing down to talk

Great video brother 💯💯💯💯💯