HVAC 065 example Superheat and Subcooling with digital gauges

[@Brekstahkid]

Thanks for helping me brush up the skills.

[@David-ml1be]

Well said. I do refrigerating units too. I have a coworker that charges until the sightglass is full. Thats his whole tactic. The sightglass exclusively.

[@alirahal5900]

Welcome back TY to your channel. Also I enjoyed watching you with Brian ORR.

[@love2hvac]

Bryan Orr is an all-around great guy. He inspires me and I learn from him all the time.

[@sergiomelapelas3378]

Great video l starting to use these digital gauges its confusing at first but ill get the hang of it thanks man id like to see more

[@love2hvac]

Keep at it and it gets easier. Loose general guides to help Dont worry about pressures, look at superheat /sub cooling, keep your SST suction saturated above 32 (airflow) and your LST ( Liquid saturated 10-20 above ambient) Target Superheat and Sub cooling depends on the metering device

[@sergiomelapelas3378]

@@love2hvac thank u man appreciate ur advice

[@honestman276]

Thanks from Bangladesh.

[@chesstime356]

Great thank you for sharing

[@jimmysegovia2688]

thank you for sharing.

[@hhghtheinfo4442]

Best explained

[@POLISNecro]

Amazing

[@holtrussell]

Ty, speaking of airflow and txv’s, I was visiting my brother and his wife last night. They bought a house with a 2015 Lennox system. ECM motor on the furnace / air handler and single stage straight AC scroll compressor outside. The installers noted the cooling mode dip switches in the “medium low” blower speed settings. I was very surprised / confused by that. Reputable company that did the install. Ever seen a situation like that before? Didn’t make sense to me to have the AC blower speed set to medium low.

[@love2hvac]

Without seeing the whole picture it's hard to say. Here is an example to think about. In Florida, we installed an all-new duct system, with a new unit. moved the ducts out of the attic and into conditioned space and used large ducts, we installed the largest possible evaporative coil for the matchup and dropped the fan dipswitches to low. We still had enough airflow but the larger duct allowed us to lower the fan speed. The lower airspeed meant less heat over the evaporator and a lower saturated temperature that meant better dehumidification. The larger coil also allowed us more room to boil all the refrigerant to vapor and still have efficient superheat for the txv to work and to protect the compressor. In short it lead to great dehumidification without dropping the house tempersture. We had 350 cfm/ton .05 static pressure and maintained 56‰ RH at 76°F Now that's just one senario. The likely conclusion is the fit was tired but the only way to know is to test the CFM and know .

[@yashpalsinhzala4345]

Thanks sir

[@dlp7130]

Respect

[@hhghtheinfo4442]

Plz carry-on

[@robertl.7657]

Can you change the name of your you tube channel to something like ,ac ty, hvac ty, that way pops out more when people look for hvac ,also always ask for like!👍, you're really good teaching!

[@love2hvac]

That's a great point Robert and I always appreciate suggestions. I am looking to change the name but I've had many others that pushed back against that. This was never my intention to be doing this. There are many great people like Bryan Orr, Craig Migliaccio, Chris Stephens, Eric Kaiser, Jim Bergman, and so many others smarter and better at this than. My goal is just to help people when I can, not be become known or make money. Www.love2hvac.com has a link that comes straight to the playlist. It's easier to remember.

[@robertl.7657]

People look for ac, they don't know hvac,mechanical, etc keep it simple!!!

[@robertl.7657]

Ty branaman You're are HERO!!🦸‍♂️🎯🌋,my Respect!!!

[@Hubjeep]

Thanks! I have the SMAN 360 for a couple mini split installs I did and wanted to see microns of vacuum. My friend has an R-22 system with a leak. The past two years his A/C guy has added 57 lbs of NU-22 at $100/lb (crazy when the whole bottle was $200 a couple years ago). I'm not sure if he evacuated out the original R-22 or just added NU-22. They should not be mixed says the internets, but keeping an old system going for another year I wonder if it's something some just do. I'm not touching it!!

[@scoobtoober2975]

My r22 ac has been low on charge for years. I just cut the whole unit out. Taking the Schrader caps off one has a leak for sure. Little spurt. I'm sure there's other leaks but not sure. The indoor coil ices up is the end problem. Throwing in expensive gas, over and over is so dumb. I didn't want to waste any money on one that is old. It's probably 20+ years old. I bough a sm480 and more ports isn't always better. Maybe convenient for things, but it's a bit old and needs a rebuild to do deep vacuums. It'll hold around 800 mics but not lower. Pressure up it works good. I'd hate to be ignorant to whats really going on with a system and keep calling someone out to add and add add. Greedy company, not informing the customer. Or gouging on a replacement quote. Or customer is insane.

[@joeoehm4341]

Can I connect the bottle for charging to the "red port" on the manifold, instead to the "yellow port"? Because I`ve a mini-split and the "red port" is free. I would like to use the "yellow port" only for recovering refrigerant. I have 2 knobs on my bottle, for liquid and gas. This means I wouldt have to change any hoses. Or is there something against doing it this way? Could the SMAN be damaged as a result?

[@arianagandhi7634]

my question is how to know if your saturated temperature is enough for my unit ?

[@rteaw]

nice explaining but where do i find the numbers for example for my pump toshiba daiseikai ras35.. im using it for heating mainly and i would like to check that its working effectively

[@love2hvac]

I usually see Toshiba in ductless units. they charge by weight and line set length most of the time. a completely different method I have not yet discussed.

[@smokex2d309]

Amigo , pero el super heat se calcula con bulbo seco y bulbo humedo? O ese manometro te calcula todo auromaticamente?

[@hhghtheinfo4442]

Good

[@apachechoice2538]

Hey, I don't understand measuring superheat a little bit. On the ParkerSporlan website in the literature tab, you can find a lot of interesting documents explaining the operation of ac system. There i found: " The important thing to remember is that the pressure-temperature relationship as shown by a P-T chart/ application is only valid when there is a mixture of refrigerant liquid and vapor." So, in car system if i want to check SH i have to measure temp. on outlet pipe from evaporator by clamp - ok. But i cant measure pressure exactly in point of evaporator where is mixed liquid refrigerant with vapor, cause there is no LP valve, LP valve is usually on suction pipe on compressor so there is or should be 100% vapor, how my pressure shown on the gauges is reliable to that pressure which is in the evaporator where the liquid mixture is ? or i misunderstand it?

[@love2hvac]

Formula for superheat is: Actual suction line temp______⁰F - Suction saturated ________⁰F You know how to get the actual suction line temperature, a clam on the suction line. Next how to get saturated. You can try to get a thermometer at the very beginning of the coil where it's saturated (aka liquid and vapor, aka ref boiling, aka latent heat aka change of state) But it's much easier to get the suction pressure anywhere in the suction side as it's all the same. Then convert that suction pressure to a saturated temperature (psig converts to saturated temp) it does not matter where you get the suction pressure it will be the same. Once you convert it to a saturated temperature, that's the temperature it's boiling at that's the temperature it's changing state at, that's the temperature it is where it's liquid and vapor. Even if you 50 feet away from the evaporator I can get the pressure and convert it to a saturated temperature and know the temperature at the beginning of the evaporator coil. So on your car get the actual suction line temperature _______⁰F Minus - Suction saturated (psig-temp)_______⁰F = Superheated vapor

[@alb12345672]

I don't think SH and SC is meaningful on a car. The compute controls the A/C system and there is a huge difference between idling and driving (airflow).

[@samersarah957]

Hello Branaman is possible to measure super heat and subcooling for every system? Thanks.

[@love2hvac]

Most systems. There are always exceptions. Ductless\mini splits Low-pressure centrifugal chillers, Flooded evaporators. Subcooling will very depend on things such as liquid receiver. There are other methods of charging I will get to soon.

[@mtbbiker6401]

I understand that for TXV metered units you will charge according to subcooling. Is it possible to be overcharged and have lower than normal subcooling thinking you need to add refrigerant? If yes, what problems with the unit might cause this?

[@love2hvac]

TXV charge by subcooling but you still need to check superheat. Airflow is the biggest issue,. With low airflow superheat and subcooling will be off.

[@mtbbiker6401]

@@love2hvac Thanks. I'm just a DIYer so I appreciate you taking the time to respond.

[@samersarah957]

Hi Ty! I got 2 degrees super heat and 7 degrees sub cooling after starting the system about 20 minutes so is that could heart a compressor and should remove some amount of refrigerant?🌹Thank you.

[@love2hvac]

What meeting device? It's likely you have an air flow issue or dirty coil but more information is needed

[@samersarah957]

@@love2hvac Soory Ty it’s a TEV

[@love2hvac]

It will either be airflow dirty coil or a TXV stuck open

[@caru3257]

My fieldpiece gauges couldn't take the heat and are now been looked at.

[@love2hvac]

Oh no! They pretty good customer service. My set is over 5 years old without problems. I don't use them as much as I use to but they have also survived 3 schools. I do keep the screen out of direct sunlight. Learned the hard way.

[@realestateservicessaleshea99]

Do you really like the digital gauges?🤔 I can't seem to make the jump? 🥃🥃🍺🍺🍺🍇🎳 Stay safe. Retired (werk'n) keyboard super tech. Wear your safety glasses.

[@BryanVoigt]

This is one of the biggest mistakes people make while making these vids. The superheat should be measured at the evap if you don’t have a very close coupled unit. And people making these vids should tell people that so people learning from these vids know how to do it the right way.

[@love2hvac]

It is not a mistake at all. Their is importance of both measurements and that is stressed later in this series. Every Copeland class you go to will stress the importance of measuring superheat at the compressor to protect the compressor. Every compressor diagnostics will want superheat before the compressor. It is extremely important to know the superheat at this point outside. Later in this video series, I also talk about the importance of measuring superheat at the evaporator. It's important for superheat measurements and adjustments. The biggest issue with evaporator superheat (excluding compressor protection) is the lack of a service port at the evaporator. Without this you evaporator superheat will NOY be accurate as it does not account for pressure drop of the suction line. That leaves people to assume or make guesses of that the suction pressure is which makes the evaporator superheat another guess. If they has analogue gauges it would be pretty funny watching them take a reading outside and then run inside to get the temperature then wondering how much change happens between that time. Subcooling should be taken before the metering device but now many installers do you see actually installing a test port at that location? No matter what I do there is always somebody complaining about these FREE videos. You should spend the time and money making your own videos the way you think they should be done. Be sure and spend a few hours every day answering all the people complaining that your doing it wrong.

[@BryanVoigt]

@@love2hvac first of all, I’m not attacking you. That’s obvious by my choice of the words “people” and “these vids”. Second, you totally missed the point of my comment. I specifically said “when you don’t have a close coupled unit”. Did I not? I’ve watched tons of AC vids on YT and only one guy, an older guy, mentioned that superheat should be taken at the evap when you have a long line set. You and all the others never even mention it. You want to try and teach young techs how to do things? That’s great, we need more teachers, but at least give them all the info. Any time I have the system open or on a new install I add a vapor line service port right at the evap. They’re $15 for a 2 pack and it’s only 10 minutes and your equipment is already there. A vapor line service port at the condensing unit will always be affected by high ambient temp and line set length. And finally, if you’re talking about all the investments made in making these videos like it’s a huge burden, stop making them.

[@scoobtoober2975]

r22 my vsat is 10. no wonder my coil ices up. Bubye system. You old and leaky

[@hhghtheinfo4442]

Good