Ah, it's time to chill out and get ready for a mediocre. Qa live stream if you're old enough grab yourself your favorite adult beverage and if you're not stick with apple juice, put your feet up and relax. If you have any questions, feel free to ask them in the chat and now, let's queue up the intro music yeah, I think nightbot jumped the gun there bill curious, HVAC guy, he kind of put the movie quotes in there a little too soon. I usually like to do those a little later in the stream, but Bill got it right, but as it Scrolls back through, let's see if anybody else can guess it too.

So hopefully you guys are doing well a little bit slow here. Cooling off we've got some cooler evenings so and you know still kind of warm during the day. I think today it might have been 75 80 ish or something like that and then on Friday. I think it was 90.

You know so we just kind of go back and forth. This is our fall weather here, where we have cool nights and warm afternoons. So but hopefully everybody is doing great. Let me see what else ya curious, HVAC guy.

You definitely beat the system there, but Mitch holder, hey man, I'm glad you're here, but thanks to everybody that came to the stream. Hopefully I can hold up to your expectations of what do you expect this stream to be you guys? I just want to start off with a little introduction, because we have a lot of new people showing up coming into the videos and stuff, so just real, quick. Okay, my name is Chris: I'm a HVAC service technician here in Southern California, small business owner a partner in a business - I should say I'm part owner, but I I make these videos originally started, making these videos that I make on YouTube and doing these live streams For my employees and then decided to make them public and then just share the little bit of knowledge that I have okay, I want to be right up front with you guys. I do not know everything, nor will I ever claim to know everything.

Okay, a lot of the stuff that I share in my videos is mistakes that I've learned from okay and I like to give warning and advice in hopes that I can prevent other people from making the same mistakes, because I've sure made a heck of a lot Of mistakes over my small career, so you know I, I release typically two videos a week all the last week. I didn't release a video on Friday, but I typically release the videos yeah Friday and Monday is usually my go-to days. So I like to get to in a week and then then I do these live streams to kind of recap: everything, okay! So for those of you that already know this get it, but there's some new people in here. So so I typically like to show the work that I do.

I work in restaurant refrigeration, as 99 % of my work. I do HVAC refrigeration. I don't do any hot side work, but I do do you know gas fired heaters and stuff like that? Okay, I do not have any more knowledge than any of you. Guys can have.

The only thing that I do is I just like to read stuff, I'm a very curious person. Okay. I, when I don't understand how something works. I dig into it.

Okay, I got a bunch of comments off of my latest video. My latest video was a walk-in cooler that was not working in the morning, but then in the afternoon it would work fine, okay and that was kind of a misleading title. I was kind of trying to grab people's attention with that, because that is a very common service call that we get in this fall season that we have here in Southern California. Okay, we have mild winters here which leads to a little interesting thing and I'm going to discuss that's kind of kind of lead me into some other stuff too, and I'll talk about it in a minute.

But we have mild winters and we will have you know cold evenings, but then we still get warm during the day and that leads to all kinds of interesting problems. Okay, we do use head pressure controls and, in my situation for my latest video, we had a head pressure control that was bypassing like it was supposed to. It was doing its job, there's nothing wrong with the head pressure control: okay, a head pressure control valve. I should say alright, but what was happening was there? Wasn't enough refrigerant left in the system for the system to operate properly with the head pressure control valve? Okay, so the purpose of the head pressure control valve - and I know I'm going to cover some stuff - I've already covered, but it needs it because a lot of these are totally misdiagnosed valves and misunderstood valves.

Okay, so the head pressure control valve is just one of the many means of ways to control the head pressure or the condensing temperature in order to help the expansion valve work properly. Okay, so our expansion valve typically thermostatically-controlled expansion valves. We still need a head pressure. Control on a electronic valve, but thermostatically expansion or thermostatic expansion valves really require that head pressure control when we get low m and so okay and guys in the chat I will address and I'm not paying attention to it now, but I'll definitely get to your guys's Stuff, okay, so I'm just gon na keep going on my little tangent right now, so the head pressure control valve is there to help to maintain a pressure differential across our expansion valve.

Now I have an expansion valve. This is a thermostatic expansion valve right here that I did a cutaway on okay. So what happens here? Liquid refrigerant comes in and it's metered through the orifice and the expansion valve, and then it comes out the other side. Okay, we need this expansion valve to meter that refrigerant at a certain flow rate.

Essentially, let's, let's call it that, okay and in order to do that, it has to have a certain pressure differential. So you have to have so much pressure pushing on one side of the valve so that way it can, you know, push the refrigerant through the valve and meter it. Okay change the state of the refrigerant from a liquid to a mixed vapor, essentially, and we we do need, we do have electronic expansion valves also. This is not.

I do not have a cutaway of an electronic expansion valve, but this is an example of an electronic expansion valve now the head pressure, control of is one of many means of head pressure, control and again, like I said it's there to maintain a pressure differential. So when it gets really cold outside our condensing temperature drops okay, when our condensing temperature drops the the driving force of the refrigerant is not quite there anymore. Okay, you need that really high pressure that somewhat high pressure in the system to push that refrigerant through that valve, okay and the lower that driving force gets the harder it is to push the refrigerant at the proper flow rate through that expansion valve. That's our pressure differential, so the head pressure control valve essentially simulates a blocked off condenser or a smaller condenser.

Okay. So what it does is it backs refrigerant up into the condenser kind of like if you would block the condenser off with cardboard, okay and it drives the head pressure up kind of like if you had a dirty condenser alright. But it's not as easy as just blocking the condenser off this valve actuates, as the pressure in the system raises and lowers. So when the pressure raises the valve will throttle down and then when it lowers it'll, you know close and start bypassing it.

It goes back and forth okay, so it's not just like on/off on/off, it'll, actually kind of regulate. It's a very small regulation there, but it will move. Okay or modulated, I should say, is a better word now. They're often misunderstood, because a lot of people tend to think all the head pressure control valve is failing, that's what's causing the system not to work in the wintertime, that's not necessarily true.

Now, in some cases, the valve can fail all right and I'll get into that too, but oftentimes for the system is low on refrigerant. Now, in order for the system to work properly, there has to be an extra amount of refrigerant added that sits in the system. It sits in the liquid line receiver, all summer long just sitting there not even being used okay, and it's called our winter charge that winter charge needs to be there for that valve to work properly, because when the valve goes to bypass what it does is it Shuts off the flow coming out of the condenser okay, and then it takes discharge gas that the high temperature superheated vapor coming out of the compressor and dumps it right into the top of the receiver. But here's the problem.

We need a hundred percent liquid refrigerant coming out of the expansion valve or going to the expansion valve for the expansion valve to work properly. And if we don't have that liquid refrigerant going to the expansion valve, it's not going to feed refrigerant properly, okay and then the whole system is gon na fall off the map and stop working. So what happens? Is we have that extra winter charge that calculated amount of refrigerant always sitting in that receiver, and when that high-temperature high-pressure vapor dumps on top of the receiver, it pushes the liquid to the expansion valve? Okay, so there's still that liquid seal of refrigerant, they call it a liquid seal because picture it's just in the bottom of the receiver, there's just liquid sitting in there waiting okay. So when, when we push that liquid down that the expansion valve continues to work properly, the system operates, but when that liquid, that winter charge is not there because of a refrigerant leak, then we have issues with the system.

Okay, in my situation, the pressures were so low that it was causing the system to short-cycle turn on and off on and off, and my box temp was about 55 degrees. Now it only took about 4 pounds of gas. Actually, it initially took two pounds of gas to clear the sight glass. Okay.

Now that system holds about 18 pounds of gas is my estimation: okay, because the winter charge on the system was 14 pounds so, but that system only took about two pounds of gas to clear the sight, glass. Okay, another misconception that a lot of people argue with, but this is truth. Okay, and this is how this works is. Is you need a solid column of liquid going to your expansion valve the the sight glass if it's installed correctly and there's no restrictions before after it the sight, glass and needs to be clear for the expansion valve to work properly? Okay, I know that's an argument.

I know a lot of people don't agree with that, but that is the truth. If you read any spoilin documentation, it says that their expansion valves need a solid column of liquid going to their expansion valves period. Okay, not a liquid vapor mixture. It's solid column of liquid now I kind of just covered that a little bit.

Hopefully, that explains some things. I've talked about head pressure, control valves many times. The simplest head pressure control valve to understand is the l AC valve okay. This is Spore lens l, AC valve.

This is a 3-way valve, essentially, okay, it's three three ports on it, and basically one port when the system is not by passing. The refrigerant does not flow and that's the the discharge port okay, so they actually have now. Unfortunately, on the side that I cut away, this is a valve - that's not cut you guys, can't see it, but stamped in the valve body is letters so see for condenser. This is the line that goes to the condenser D for discharge.

This goes to the discharge of the compressor and r4 receiver. Okay, so when this valve is not bypassing, the discharge is going to nowhere alright and the refrigerant flow when it's not bypassing, is coming out or into the the C from the condenser and going directly into the receiver. That's the normal operation. So hopefully that answers your guys's questions or kind of clarify some things, I'm going to talk a little bit more about it too, but I want to get to some questions and comments in the chat and then I'll get back into the head pressure control valve stuff.

So, let's see what we got in here, what am I missing here? I know primetime, you hate, Head Master valves all right. Let's say I'm going to start down at the bottom, so if you guys posted something that I didn't get to definitely reposted again, okay, so Joe, you asked what was my receiver level after the winter charge. Okay, the receiver level was just under half right at about half and the way that I obtained the receiver level is when I was all done, charging the system I pumped the system down then took a heat producing device that did not exceed the high temperature limit Of the receiver or the soft plug on the receiver and I went up and down, I passed it up and down the receiver, and then I took my fingers very carefully and went from the bottom of the receiver up until it got to the hot point. Okay, what I was doing was where it's not hot, is the liquid refrigerant and then all the sudden when the receiver gets really hot.

That's the vapor refrigerant. So that's how you know where your liquid level is in the receiver, be very careful, I'm not going to tell you what kind of heat producing device to use, because you can definitely cause some damage and hurt yourselves, be very, very careful with that. Okay, all right! Let's see what else we got going on, does the rule of thumb actually work? Ryan Guzman, I don't know what you mean by the rule of oh. You have heard it does, but at the same time it does - and I don't know what you mean by that Brian Guzman - clarify what you mean, but rules of thumb.

Okay, let's see what are the ideal: evap saturation temps and super heat settings for walking, coolers and freezers. So, ideally again, this can all be changed by an engineer if you have funky stuff going on, but a general product, walk-in cooler is going to have about a 10 degree, evaporator TD, okay, so your evaporator temperature is typically going to be 10 degrees below the air Temperature, now you need to be very careful when we're talking about evaporator temperatures, because now that we have these really high glide refrigerants such as 448, a there's a lot more. That goes into it and you need to understand how the glide works so, but we're gon na use the really easy ones and that's r22. So for r22, my typical evaporator temperature is gon na, be about 10 degrees below the box temperature.

Okay, typical box temperature. On a normal walking, cooler is about 35 degrees, okay depayne. There could be other different situations: okay, but typical general products: okay, walk-in freezer you're, typically going to have about the same evaporator tea about 10 degrees. The super heat settings, depending on what type of evaporator coil you have are going to change or what kind of metering device you have.

Okay with a TXV or a thermostatic expansion valve like this on a walk-in cooler, you're, typically going to see anywhere from about 10 to 12 degrees, evaporator superheat, but it may go a little bit lower. It just depends on what kind of compressor protection you have. Okay on a walk-in freezer, you're, typically going to see somewhere between six and eight degrees of superheat, evaporator, superheat, okay, but again everything can change depending on what in what the customer keeps in their box, what kind of humidity levels they want! Your TV can go up or down all kinds of stuff: okay, um, let's see what else we got that does not have a sensing bulb. Can the switch be mounted anywhere inside the evaporator cabinet? What do you mean by Kyle Carmen? I don't know what you mean by that, but I don't know if I'm walking into what does not have a switch.

I did give me some clarification on what you're asking me there, but okay, so Michael Ryan, great question and I am gon na get into that right now. Okay, so any reason why head master or head pressure control valve used over a fan control for head pressure control, so it really depends on the situation now. This comes down to personal preference, so I live in a very mild climate and what I mean by that is, we typically don't get extremely cold. So what happens when I install a fan cycle switch, especially if I have a condensing unit that has a single condenser fan motor.

When I install a fan cycle switch, we have short cycling of the condenser fan motor okay and the reason why we do is because we have mild temperatures here. So my you know, average temperature during the day is fifty five to sixty degrees. So when we shut off a fan cycle control, the condenser fan motor is going to shut off, then the head pressure is going to be driven up. Pretty quick and it's going to happen and what happens is it's kind of violent on the system? If you ever put a set of gauges on a system when, when the fan cycle controls, turning on and off, like that, you'll start to notice that every time the fan cycle control turns off the liquid drains out of the does sightglass and then, as the head Pressure builds up, the liquid builds back up and then it's just like a vicious cycle, and you start to notice that the box doesn't perform as well, because that liquid is kind of you know.

The the state change inside the condenser is kind of fluctuating here and there now, as you get to bigger condensers, and you have more condenser fan motors, you can stage the condenser fan motors then fan cycling does pretty much okay, all right, but when you have a Single condenser fan motor. I personally don't like using fan cycle switches because I notice that it's a really violent and it kind of affects the operation of the system. That's not to say that fan cycle switches, don't work, I mean you know, I mean they work. Fine! It's just what you're trying to control okay, different situations now, if you're using a lot of hot gas defrost, you need that head pressure to be consistent and you don't want it.

Turning on and off a lot - or you know fluctuating again mild climates here in Southern California, so fan cycle switches can tend to be a problem. But I have plenty of systems out there that have fan cycle switches and they have for 20 years and they work. Fine, just a personal preference head pressure, control valves, in my opinion, work fine, but that's just my preference. Okay, I will go out on a limb and I will say that majority of the problems with head pressure - control valves are improper installation or improper refrigeration practices.

One of the most common ways that a head pressure control valve fails is when it gets stuck open. Alright, so you go out there in the summertime and you diagnose a bad head pressure control valve because it's leaking by or discharge gases. You know causing the head pressure in the system to go up. It's leaking through a lot of times.

That's because something's stuck inside the valve, I mean, if you look at the inside of an l AC valve, there's really nothing to it. There's a spring a rod and a seat, and that's it, but there's a very, very small area for the refrigerant to flow through any kind of contaminants can can clog up that valve and cause some problems. Now you can also lose the dome charge. It works similar to an expansion valve.

It has a power head essentially on it that pushes down and opens and closes the valve, so those can fail. This is not a field replaceable part. They do not sell those at supply houses. At least I've never seen them for so you usually have to change the whole valve.

If that situation happens now, there's a few more mechanical functions inside some of the other head pressure control valves. This is an Ori believe or or yeah. I believe that's what this is called and these have a few more mechanical parts inside, but they still work with the same concept. It's just a valve.

That has three ways. I don't have a cutaway of this, because it's much harder to cut apart at one point. In time I had spoilin send me cutaways, but it was just on a temporary. They loaned them to me, so I could take some pictures and show them in a stream.

I do have some other videos with head pressure, control valves and live streams and different things. Like that, if you go way back in my channel or if you just search head pressure, control valves you'll see some stuff in there, where I show some cutaways of different valves. So hopefully that answers your question about the fan cycle controls. I have systems out there that have fan cycle controls and head pressure control valves at the same time.

So it really depends. Let's see what else we got, I'm sure I'm missing a bunch of stuff in here. Okay, so what causes Randee labs? What causes static charge? Coming off charging hose when charged in a unit, I can tell you that that's because there's no ground and you're creating a static discharge because of how fast that refrigerant is running through that rubber hose and it's creating a static discharge. I have seen that I don't really have a solution to it.

I imagine that if you ran a ground wire from the refrigerant tank to a ground source, then it wouldn't happen, but I realized that that's not very practical, but I've seen it on. So I got an old CPS scale that it actually shorted out the scale. I was watching it one time and I saw the spark go from the tank to the scale and then the scale went blank and never worked again. So, let's see what else? What am I missing? All right, hey Joe.

Thank you very much man. I really appreciate that super chat. That was very nice of you. Thank you.

Thank you. Let's see what else yeah Brad Taylor. It is fluid ounces. I believe, but you know I use the that the scale to weigh it.

It's probably not correct again, I'm not expecting it to be the exact number, I'm just looking for a gross under George. So yes there. I believe that refrigerant oil is in fluid ounces. So, let's see what else and okay, so I've got a couple different topics I want to cover and I want to go ahead and get to these and then we'll start going through some more questions that you guys have.

Okay, so, first off, I want to start out by sharing the PDF again one more time. So this is the spore'ln 90 31, and this is how I this is how I calculated that flooded charge. Okay, so I definitely put a link inside there. That's how I calculate the flooded charge.

It is really not that hard guys. A lot of people said. Oh my gosh. That was really interesting.

All those calculations guys this is just a little. I mean this is like a five page book. All I did was read. I mean actually it's not even five pages.

There's two pages of text: there's really nothing to this. This is the 1991 bulletin. There's really nothing to this there's two pages of text and then there's two and a half pages of numbers and charts to use where you get your density factor and your equivalent length for return bins. It's really not rocket science.

Just reading these things and inputting the numbers, you follow their formula, it's a super, easy calculation and if you're so inclined, you put it into an Excel spreadsheet and boom. You just input some numbers really not that difficult to do. Okay, so it's not rocket science. Doing that thing Tom, you asked: how often do I change my filter on my info condi text select, probably not enough Tom, I would say in all honesty, I probably if I notice that I feel like the leak detectors, not working I'll, look at the filter and See if it's dirty and if it is then I'll change it, but I mean I don't know how often that is six months a year.

It's not a regular thing. I probably should be changing it on a regular basis, but I don't so all right. Let's see HVAC apprentice, HVAC our videos house, then oh yeah, that's a different person that that was a you're, probably thinking of ernesto hvac, our vlogger he's the one with the new company where's the best place to buy for 10 a in california area birth. I don't know man, I really don't shop refrigerant prices, I just go to my main supply houses and buy the refrigerant, so the supply houses that I typically will use our RSD, allied refrigeration, united refrigeration, are the three main supply houses that I use and then every Once in a while I'll go to Train or carrier, or something like that or air coal, there's something you know to get whatever particular brand, but for the most part I shop at United, allied and rst.

Alright, let's see what it is. If I cut the headmaster tube at the top, what will happen to the valve fully open HVAC apprentice? So yes, if you cut the pigtail on a head pressure control valve, then the valve will not bypass anymore. But if the valve is stuck open, it might just be stuck open because there's sediment or some kind of contaminants stuck inside there - okay. So but yes, if you clip the tip on the power head, the valve will not bypass any more and it will go to normal refrigerant operation.

Chad. Thank you very much for that super chat. That was really nice of you. I really really appreciate it, but let's see who makes the best compressor HVAC kid.

I don't know I'm it really depends on what I'm working on to come see your copeland. They both, I think Koplin, probably makes the better scroll compressor. They have all the technology. I I do fine with just a normal reciprocating compressor.

It could be to come, see our Copeland either ones. Fine with me, I mean compressors, a compressor. You know I mean they tend to pump the same. I don't know if there's really one that can take more abuse.

I will say that the man Europe compressors and the danfoss compressors and the Train 3d Scrolls. They are pretty bulletproof when it comes to liquid refrigerant, but then again so are the Copeland Scrolls so yeah. I really don't have a preference, but if it's a scroll Copeland, probably but other than that to come, see Copeland, I'm fine with them all. So, let's see what else can I get anything less than 25 pounds of 410? You only need about four pounds now you you get, you buy it in a 25 pound jug.

I mean yeah you're, not talking that much for a 25 pound jug. So a couple hundred bucks not that much at all, let's see what else all right! So, okay, another question that I have is: why did I go through all that trouble in my recent video to calculate the flooded charge? All right, I don't always do that calculation when I am charging a system all right, I'm now I'm gon na be honest with you guys, oftentimes. So once I figured out the proper flooded charge, what I will do is I will pump the system down and I will mark the liquid level in the receiver with a paint marker. So then, if I ever find a low charge issue again, I know where the liquid level is with the proper flooded charge.

So that way, I don't have to do the calculation every single time, because there is instances, for instance, if you come out to a yeah, you are right, Clint good job on the guests there, but Big Trouble in Little. China is the movie quote. So if you in the summertime, if you walk up to a refrigeration system, that's low on charge all right! Well, how low is it you, don't you know, or actually no in the summer times, not a good, but there's there's instances where you can walk up to a system and you don't know how low the charge is and sometimes there's that weird instance for summers, and I can't think of it right now, but I thought of it earlier: there's that weird instance, where you can't you don't know how much refrigerants been lost from the system. Okay and it's not feasible - sometimes to recover the charge and weigh the whole charge in.

So if you, if you can calculate the flooded charge, you go through the trouble of it, then once you do that mark the receiver level and then from that point forward, you can fill it up to that receiver level, because you know where the receiver level should Be when it's pumped down okay, so that is one little quick method of doing that. Okay, let's see what else, what can cause flooding back at compressor, suction line? What can cause flooding back at compressor, suction line and you're? Asking me if it's the t, -- xv? Well, different things can cause flooding back to the compressor, all right when you think about the t, -- xv, it's doing its job because it's it's trying to control the superheat okay. Now, let's just say, for instance, you have low airflow or a dirty evaporator. I would expect to see super heat up the compressor if you have low, airflow or dirty evaporator, okay, because the expansion valves still trying to feed the right amount of refrigerant through the system.

But you just don't have the airflow for heat transfer there for your refrigerants. Not boiling off in the evaporator, therefore, you might get really low, superheat or flooding back to the compressor other things that can cause Tia flooding back. Yes, is a failed expansion valve that's flooding too much refrigerant. It's an oversized expansion valve all kinds of different things can cause it alright.

So I like to start out when I'm going to diagnose things is don't jump the gun, walk into the system or walk into the situation, evaluate everything. Does this look like a million people? Have worked on this equipment and if that's the case, do you think it's possible? They put some parts on there that aren't correct in that situation, I probably start with a really quick load. Calculation call, my supplier. If I can't do it myself, given the box dimensions, ask them how big the evaporator should be asked them.

What size expansion valve should be in the evaporator. You can also do all this stuff. You can just ask the Google, you know and it'll it'll tell you all this stuff right once you've verified that the equipment's the right size, if you see that it has a new compressor and it did, they put the right compressor, because I've seen situations where people Put compressors that were too big or too small in systems way in a condensing units, a different size. Thank you very much Zack.

I really appreciate it. You know, so it all depends on what I feel when I walk into the customers location in that situation. Once I have evaluated the system and found out that all the components seem to be the correct ones, then I'm gon na start checking things. Ok, you're gon na start checking superheat at the evaporator, and you may try to make an adjustment but definitely want to make sure the system has the right charge before you do that and and go from there.

Okay. So hopefully that answers your question. If I don't answer you guys's questions, HVAC our videos at gmail.com I'll be happy to answer them there too, as a tech storm Donald. Thank you for the super chat by the way, and you asked me as a tech.

How do you help customers move forward with repairs Thanks? Okay, so it really depends. Alright, I put a lot of information in the customers lap, but at the same time I don't put too much information and I know that's a hard thing to figure out. Alright, I'm not gon na go to the customer and say: hey guess what you know: you're compression ratios off the amp draws really low. You know the system's not performing.

You got a bad compressor. I'm probably gon na go to the customer and say hey. You have a weak compressor, it's time to replace all right too much information is going to confuse them in certain situations. Hey your evaporator super heats way too low.

I tried adjusting the valve. It's not working, you know it's just you. Don't wan na give them too much information, but you also don't want to go in there being very vague and not explaining to them what's going on, so you do have to find that happy medium of how to approach them with the problem. Thank You, Chad.

I really appreciate that, but again Wow super chats awesome, but thank you so much so you know I just try to educate the customer, but there's a lot to it. It's not just going into the restaurant, i'm i'm using restaurant because that's what i work in, but it's not just walking into the restaurant and telling them what's wrong. It's building a relationship with the customer. Okay.

The first thing: i don't care who you are the first thing you do. Is you walk in and you shake the hand or bump fists with your point of contact, all right, the manager, the maintenance person, whatever you say, hey how you doing today, i'm here to work on this. You ask them. You know sometimes they're too busy for you, but you try alright how's this thing working.

Has there been any history? Ok, it's just been my company. Ok, but do you know what we did? Ok, i'm gon na make. Some phone cannot trust. It's very important to make eye contact with the customer, but then you know, especially when you're talking to I'm not trying to single anybody out, but especially when you're talking to female managers and female points of contact, you don't want to make them feel like they're.

Small same thing goes with the gentleman to either way. Ok, but you want to go in and be on their level. You want to say hi, you know, explain everything. This is what's going on the system's, not working because it has about expansion valve.

But again I never go in there and say this is what's wrong. I always give myself a little buffer room and say: hey. You know what the unit currently has about expansion of, but we need to change that part before we can evaluate anything else, always give yourself a cover-your-ass kind of thing. Alright, that way, you can that way they understand like Hey, he came in and said all he needs to do is change the expansion valve and everything will be good, but then it isn't good all right and I'm not trying to say to give yourself buffer.

So you can cheat them or anything like that, but you always want to give them that little bit of buffer room. So that way they understand that hey this unit has a refrigerant leak. I need to top off the charge first, you know or whatever they want. You to do then find the leak and then we're gon na evaluate the system from that point forward, I can't tell you if everything else is working.

Fine, I can't tell you if the temp controls working find all that stuff. Until I get the system charged and operating properly, okay, so hopefully I didn't go off on too much of a tangent. I kind of answered your question there, but thank you very much Juan Carlos. That was really nice of you, but let's see yeah customer relationship is a huge part of the job all right.

So someone had asked me in the comments of the video that I released. If you have to calculate the winter charge like I did. If the system does not have a head pressure control valve okay, no, you do not. If the unit does not have a head pressure, control valve you clear the sight, glass or get it close to being clear till the box comes down to temp, then you, you know clear the sight glass once it's closer being down to temp and you call it A day you do not have to add extra refrigerant if the unit does not have a head pressure control valve.

Okay, all right do all Trane compressors have built-in accumulators, Nicolas Pope. That is a question I do not know the answer to, but I don't know about a built-in accumulator. I think, by design the way that the scroll compressor works. It can handle more liquid refrigerant, but I don't know about a built-in accumulator so never heard that one before what is going on yeah, okay, Joe all right, let's see all right, let's see what else we got.

Okay, I'm going through my list of things so Thomas, and this is kind of a change of subject here but Thomas had asked me about discussing he's in school and he wanted me to discuss VFDs because I mentioned VFDs in my videos and he just didn't understand What they were, okay, actually no he's not in school he's in residential, so he didn't understand the purpose of a VFD. So a VFD is an acronym for very frequency. Drive. Variable frequency drive typically controls a motor, okay and there's many purposes for having a variable frequency drive.

Motor protection is one of them. They often have a lot of built-in motor protection. They have all kinds of safeties that can can shut a motor off before a circuit. Breaker or anything like that, would normally catch a problem.

Okay, but one of the biggest features about a variable frequency drive when it's controlling a motor or a pump is the ability to change the frequency which is going to slow down and/or speed up the motor. So, on the most for the most part in my videos, VFDs are used in packaged units. Okay, oftentimes, we'll see them in a package unit, and it's what it's doing is on the package unit. It's like a carrier package unit that I've showed in VFDs and they have all kinds of problems.

It's a title, 24 thing: okay, it's an energy standard that we have here in California. That's quickly going all across the nation. But what essentially it is, is it's a two-stage, blower motor okay, so think about this. If we have a ten-ton packaged unit that has two five ton compressors in it, the typical rule of thumb - and this is a rule of thumb, again you're gon na change.

This number, whenever you balance your building out and adjust your air flows, but the typical rule of thumb is that you're gon na have 400 CFM s of airflow right: /, 400 CFM CFM's of air flow per ton of refrigeration. Okay. So if you have ten tons of cooling, you're gon na have 4,000 CFM's of air right. Okay, so we have 4,000 CFM's of air and we only have one compressor running in the air-conditioning unit.

We are now overshooting our air flow theoretically and we're not getting. Let's say the proper heat transfer in the evaporator coil we're pushing air through the evaporator coil to fast okay, because there is times - and you know where you don't all necessarily call for both stages of cooling. So in that situation to save energy, what they do is they install a VFD variable frequency drive to slow down the motor to a predetermined speed. So that way it can deliver.

Let's just say 2000 CFM's of air, when only one compressor is calling and then when the and compressor comes on its gon na stage up and deliver 4,000 CFM's, whatever it may be, whatever the designer has designed that easy to do. Okay, so in that situation, that would be a purpose for having a VFD now, there's other instances where we have VFDs. We also put them on exhaust fans when we want more precise motor control. Okay, we have super technologically advanced its exhaust systems for restaurants, mail Inc has a system called Intelli hood and what happens is it has a bunch of VFDs and there's all kinds of optic, sensors and heat sensors and whenever it gets really hot in the kitchen or There's smoke inside the hoods, then it speeds up the exhaust fans to a higher speed until all the smoke goes away and then it slows down the exhaust fans to save energy, so there's all kinds of purposes that we might use a VFD for.

So hopefully that answers your question for you, but there's tons of other purposes, but those are the instances where I use in the most. So let's see what else we got, what am I missing here? Okay, so Glen you're about to purchase a used dairy farm, but milk cooler, okay, Oh bulk, milk cooler. What would I recommend to prevent contamination of the refrigeration system? Well, if you're purchasing a milk cooler all right now, it just depends. Is this a remote refrigeration system? I'm assuming so because it's a large milk cooler, so I'm assuming that the condensing unit is remote.

So, if that's the case, then a proper shutdown needs to be done, but I would say, probably at a minimum that whenever you have the new equipment installed, you probably go ahead and change the oil and the compressor and make sure that whatever service company you use To install the equipment does a proper install, they change the dryers and they probably should change the oil because you never know what happened before you got it. Okay, if that equipment is working properly, all right, there's definitely a lot more that you can do. I kind of need a little more context to your question, feel free to send me an email to hvac our videos at gmail.com, and i can probably help you out a little bit more. So, let's see what else okay, HVAC rookie asks hold on.

Okay, so HVAC rookie, you said: if I find a system low on oil. How do I know how much oil to add HVAC rookie? That is the ultimate question. So the bigger the compressors, the more kind of oil control they have, they often will have sight glasses. They will often have oil level controls and different things like that.

But when we're dealing with you know just light commercial equipment, a five-ton compressor for an air conditioner, they typically don't have any way of telling you how much oil is in that system. So the only way to really do a test would be to go ahead and pour the oil out of that compressor and compare it to the amount of oil that should be in the compressor. Now. If it has an oil sightglass, you can fill it to a proper level in the system, but here's the question: where did the oil go? Alright, that's the ultimate question.

If you have a compressor that has not had any refrigerant leaks, but all the sudden it's low on oil, that oil is likely still in the system and if you just add oil to the compressor. The fear is is that that oil will come back to the compressor and and damage it and or the new oil that you add to the system will disappear into the system too. Now, if you have refrigerant leaks, it's possible that the oil leaked out, but that's a lot of oil. So you know that is a real question.

I don't have very good experience with adding oil to compressors for the most part, if a system has run in a compressor with low oil, the compressor and my aunt, my chances most of the time is already damaged and it's time to replace the compressor. But if you do proper preventative maintenance and your regular on it and you can catch a problem before it becomes a big issue like you just start to notice the oils a little bit low but not really low, then you know you probably could save it by Adding oil, but you need to figure out where the oil went. Okay and you need to figure out some sort of methods to maintain that oil and make sure that it stays inside that compressor, there's all kinds of mechanical stuff you can add to systems. I really don't see them very much, but there's things like oil separators that take the discharge gas and they run it through a tank.

Basically that captures the oil and brings it back to the compressor. So if it ever does leave it won't ever leave the oil separator, there's all kinds of different things you can do so yeah, let's see what else we got going on mr. ice. Do I rebuild or replace semi-hermetic compressors honestly, I don't come across semi-hermetic compressors.

Very much anymore, mr. ice, I have rebuilt well, I shouldn't even say rebuilt. The most I've ever rebuilt on a compressor is just doing valve plates. I've never changed Pistons or anything like that, because I work on smaller stuff.

So it's not really economical. For someone to spend all that money to to rebuild a small little half horsepower, three-quarter horsepower semi-hermetic it's easier for you to junk it and just put a new one in get a core on it and you know call it a day, but the bigger they go. The more cost-effective it is to rebuild them, and I know on the supermarket level they often will rebuild compressors if they are similar medics. So, let's see what else our two compressor circuits better than one tandem HVAC kit, I mean that's a questionable thing.

It depends okay, so two compressor circuits I mean on a tandem system. You're gon na have to have some kind of oil control on two compressor circuits. You could just have to scroll compressors. I don't know you know.

I don't know what the the cost evaluation is on a parallel compressor system or a tandem versus just two separate circuits. I'd. Imagine you'd have to have some sort of capacity control. If you have tandem, compressors, so yeah, I I really don't know which one's gon na be better, which ones a better situation.

So I mean I could see upsides and downsides to both off the top of my head. One of the upsides is as separate systems that way you don't have contamination issues that affect both compressors. I mean if you follow most manufacturers, recommendations like on a train. You know in telepak unit or something like that.

I mean most people don't do this, but if you have a failure of a single compressor and a tandem situation, they often will tell you to change both compressors, especially if it's a burnout I mean, I see people not do it, but I mean in a situation Where you'd have two separate circuits, there's no chance of contamination getting between those circuits. You know it's kind of hard to say. Let's see what else Adam you said, your compressor is louder than normal, but think lubrication or overheat can be the problem. It's always possible that lubrication is the problem.

You can see overheat issues if it's louder than normal. You can thermal-imaging cameras, but unfortunately, if you don't have a compressor to compare it to and you've never used a thermal imager you're not going to know what you're looking at. But if you look at a properly operating compressor, you can definitely see where the discharge of the head of the compressor is gon na, be really hot. But then you know the crank case or the suction side of the compressor is gon na, be a lot cooler and you can see temperature differences with the thermal camera.

And then you can look at a bad compress and you could say: oh my gosh, that whole compressors red there's something going on more than likely gon na, be an oil return problem or something like that. So thermal imaging cameras can definitely be. You know good use for people. Yeah supply houses do pay you for used, come or old compressors.

They want the cores, basically so really appreciated Ernesto. I, like I thank you very much for showing the channel to other people, man, anybody any of you guys that are out here. You know, share the channel out. Let's help everybody.

I just try to pass on information that I read or share. So if you guys know anybody that can use it share away, show everybody that you can, let's see what else we got going on. You wanted to ask ways. I could determine whether a system is overcharged, you're, talking refrigeration, Frank Bradley, well, first off you're, definitely gon na.

Look at your your vital signs of your system. Okay, look at your condensing temp! Look at your superheat! Let's look at your amp draw of the system. I mean: are you running a clear sight? Glass, but you've got really high head pressure. You've got really high sub cooling.

You know those are things that can indicate an overcharge. You know what you could do in a situation that you think is overcharged is go ahead and recover some of the refrigerant it doesn't matter. If you recover till it's full. Actually, what you want to do is recover till it starts flashing recover.

The refrigerant till it starts flashing then charge it in slowly from there. Okay, you want to be cautious when I say that you need to clear a sight glass. You also have to understand. You have to use common sense because sometimes, if it's an old system that was r12 and someone converted it to r22, then someone converted it to for for a that system, may not have enough volume for all the refrigerant that you need for it to work available Volume inside of it, you know for all the refrigerant that it's needed to work properly.

Okay, components may not be sized right, so you have to use some common sense when you're adding refrigerant to systems. If you think this thing's been Frankensteined and the receivers not big enough, the condensers not big enough, then certainly, as you add refrigerant, it's gon na start to be overcharged, and you know that it needs to have a clear sight glass, but there's not enough room in The system that is something that happens: okay, that happens often too, when people take like let's fit, for instance, a three-quarter horsepower, Copeland, condensing unit from the supply house and indoor condensing unit right. It doesn't have a doghouse, so you can install them on the roof, but people will put an enclosure over it. Well, if you guys look at the receiver and you look at your liquid line length - okay, let's just say a liquid line length is 50 feet.

Okay, the receiver on a three-quarter horsepower condensing unit. That's an indoor unit. It's typically going to be like a four pound receiver, there's not enough room in that receiver to store all the needed refrigerant for that long line set length. So you have to be careful.

Okay, that's why often times you guys will see in my videos if I install an outdoor condensing unit or an indoor condensing unit, I'm oftentimes increasing the size of the receiver, because I know from experience that that receivers, not big enough. You know this. This line set 75 feet long and it's running you know four coils evaporator coils. I know that I need at least you know, a seven eight, nine ten pound receiver, so I'll install a bigger receiver.

So keep that in mind you do have to use common sense. It's not just cookie cutter, just go out there and install it and move on. So when I say clear, a sight, glass, I'm not saying that you need to go out there and clear every sight, glass. You need to still look at them.

You need to make sure that everything is sized correctly. You got to use some skills and some common sense to say, okay, that receiver doesn't look like and hold enough refrigerant. You know to do all this, so hopefully I didn't go off on too much of a tangent and I kind of answer your question there, but all right any free online HVAC courses that are good. Yes, Adam Brecker.

There is some good online HVAC courses now free, maybe or maybe not depends on where you live. So there is a company out there. First off HVAC our school, my buddy Brian or produces a podcast. He does YouTube videos and he sends out tech tips.

So Google HVAC our school comm check out Brian's thing. Throw in your email address. Trust me he's not gon na spam. You guys he's just gon na send out his tech tips.

He sends out a tech tip every day and lets you know when stuff's going on. Brian is a free resource for awesome. Training, definitely check him out now. There's another training organization out.

There called HVAC our edu all right and they also operate under another name in Southern California, called it's about Q. They oftentimes will have subsidized education, meaning free to you or a very small price paid for by your utility companies, okay or essentially paid for by us. In the long run but paid for by the utility companies - and they will give you all kinds of free training too, so they will you just go to HVAC our edu, comm or HVAC. Our edu on Google just look that up or look up its about Q and see if they have any free resources in your area, definitely check out HVAC our school, my buddy Brian or he's got great information on his website.

So, let's see what I miss in here do I think, VF DS, cause motor winding damage or premature failure, Nicholas Pope. Well, there's certain things that you have to make sure happen when you have a VFD, so first off you can have premature bearing failure on motors. Okay, so they have to have what they call a grounding ring, install the special kind of chingus that goes on the bear in front of the bearing basically and make sure that you don't have any funky interference and something about the VFD and some super technical stuff. That's way above my head that causes bearing failures.

Okay, so that's one thing that can happen on a VFD: you can't just throw a VFD on any motor out there. You got to make sure that it's the right kind of motor it's got to have these grounding rings on it, to make sure that you don't have issues with the bearings now. Do I think it's gon na cause, I'm sure that there's some logic in the fact that you have to have an inverter duty motor? I would assume all right, I'm not super technically smart when it comes to what type of motor can handle a VFD. But I do know that there's inverter duty motors so I'd be cautious about throwing a VFD any motor.

Okay, so I'm sure there's some logic there. I definitely reach out to your motor manufacturers and I'm sure they can help you out a little bit more and make sure that you get the right information to know what kind of motors you need to use. Maybe some people on the chat could help you out a little bit more. So alright, let's see what else do I prefer microchannel or copper fin condensing units for refrigeration applications? I prefer old-school, copper, tube and fin condensers, I'm not a fan of the microchannel condensers.

I understand the microchannel condensers are more efficient, sure, okay, I don't like the aluminum condenser, I'm not. I really haven't had many troubles with them. I've. Just I don't like change.

Okay. Now, let me tell you something else that spoilin method: 90-30 dachuan will not work on a microchannel, condenser microchannel condensers this this spoilin method to calculate the flooded charge. 90-30. One is only on a traditional tube and fin condenser, so a copper tube condenser with aluminum or with you know normal fins.

It will not work on a microchannel. Microchannel has different calculations that you have to follow and that's a really good. You know stopping point and kind of transition into something else, so my experience with calculating the flooded charge for a microchannel condenser. I work with heat craft condensing units all the time and they have their Hyperion core, I think or Hyperion micro, whatever their condenser is called.

It's whatever their funky name is for a microchannel condenser, but they they have this weird calculation in the installation instructions and I cannot make any sense of it. I've even called the manufacturer and said dude. What does this stuff mean and the tech support people? I've talked to multiple tech support people and they basically tell you when you're charging a microchannel condenser. You just basically put the maximum amount of charge in the system.