Okay, so today we have got a rounded compressor, this guy right here, it's shorted the ground, previous tech, diagnose it we're gon na come in we're going to replace that compressor expansion valve out of suction dryer. If I cut room liquid dryer, try to you know clean the system out purge it with nitrogen. Hopefully it's not a really bad burn, we'll see, and then my understanding is, the other compressor has a refrigerant leak. They were thinking it's on the pressure control which it might be, but I also see a bunch of oil on this expansion valve right here.

I don't know which expansion valve. Actually, this is the expansion valve right here for the compressor that's running, and I see oil everywhere, so it might be leaking on the expansion valve we'll have to see so we're gon na get through this and diagnose a little bit further right now, so we're working On a shopping mall, so I went ahead and let management know to put their fire alarm on test, and then I also let the shopping mall know to put the system on test too. So that way, when I shut anything off, it doesn't set off any fire alarms ring like that. So first thing: first, we're gon na go ahead and get this grounded one recovered and then we'll diagnose the other one.

We're gon na try to leave this unit running as long as possible because this is their kitchen AC, but there will be a point when I have to shut the whole thing down. So, okay, so we're getting started on a recovery. I've got the app yanmega flow to make. You go faster, I've just some gauges on there.

Just tell me, the pressures a pion mega flow uses, bigger hoses, so 3/8 hose is going to each port, and then I've got 3/8 hoses going to the recovery machine and 3/8 hose, and then they have quarter-inch fittings on notice on the recovery tank. I've got it in ice, water and I've got it hooked up to the vapor port and inverted that we were going to pump it into the vapor. It's a lot faster, all right. So this is the recovery tank and I want to show you guys why I like to invert these tanks.

I just have loosen this and you notice first off how dirty that is. But if you look at it, that's a very, very small diameter tube sorry, my hands shaking very small diameter dip tube that essentially goes to the bottom, so the liquid port is going to come out of that and the vapor is going to come out this one. I think right there yeah this one right here actually looks like a Mike about that. But the whole thing is is that we can speed up the process by filling through the other port because we're not having to go through.

Even though it's it's small we're not having to go through this whole little tube right here, okay, so I find that filling up through the vapor port inverting the tank and filling it from here. It goes a lot faster and that's why I do it that way. Okay, I just opened it up and pushed in what I could without turning on the machine now we're gon na turn on the machine you just let it go. This should go pretty quick because we've got it all set up with the basket, we'll just watch to make sure we don't overfill this tank.

Okay, so I'd say it's been 15 minutes at the most, maybe 10 down to zero and we pulled out 13 pounds did good moving fast, so we're gon na go and shut this guy off and get started on changing that compressor, and then we'll worry about that. Okay, so we've got everything this guy's recovered, we're just starting to sand it all up. We're gon na take off these pressure controls and see if there's a Schrader port below them, because we are going to change pressure controls on the other system, because that's possibly where the leak is so if they're Schrader's then might not have to recover the charge. We'll have to see, but we're gon na do that we'll use this one as a dummy since there's no gas so trying to solve for the big picture.

What I'm doing before I put the new compressor in we're gon na dump the old compressors oil out we're gon na see if we're way low on oil charge if we're really low on oil charge, which is burnt oil. It's all nasty in that, if we're really low on oil charge, then before we braise the new compressor and we'll have to cut the lines in multiple spots and try to find out where that oil is out, whether it be in the evaporator or the condenser. But we don't know that yet so also at the same time, since this is a grounded compressor, we're changing the expansion valve at the same time, because we have all the gas out of the system and we don't know what caused it to go bad. So for a cheap enough part like an expansion valve, it's cheap insurance, so so we're just about I'm going to rock this compressor back and forth and then I'll pour it in the Gatorade bottle and then measure with my scale to see how much the oil charge On this, guy is 42 ounces of oil, so I don't know if I got 42 ounces out of there, but we'll see okay, so I pulled 36 ounces of oil out of that compressor out of 48 ounces.

Honestly that doesn't sound too bad to me because I know there's still oil in there. It's really hard with one person to manipulate that thing to get all the oil out, so I'm calling it good. I don't feel the need to have to open up the system and blow crap out we're just gon na go ahead and put this compressor end and go from there. Okay, so I'm getting ready to braise this in before I pulled it out.

I pulled the pressure controls off and check this out, so I'm changing compressor number two look at the low pressure control switch number one, the low-pressure controls are switched, so the low-pressure control for compressor, number 2 or compressor number 1. This is number 1 right here, and this is number 2, so they have the pressure control swapped. So that would kill a compressor for sure. If we had a low-pressure situation, which we weren't completely out of gas on the first state or the second stage, it was, it was just less than a pound short.

So that's not enough to cause a problem. But if we had a bad TX V or expansion valve and the low pressure switch, wasn't cutting it out, then that would possibly cause the compressor to ground out. So again you got to pay attention. You can't just slap it in like a lemming.

You got to watch what you're doing so we're checking the oil charge. That was easy. You know I'm looking at the pressure controls and I see that they swapped them. So basically, compressor number one is monitoring this compressor or compressor number one for the board is monitoring the second stage.

So if the second stage had a low-pressure problem, it would never shut off and it would potentially cause the compressor to ground. Maybe you know that's one of the things so we're gon na keep going. We don't know if that's the only thing that's going on. Okay, so we're gon na braise any expansion valve and we're paying attention to which joint we're doing first, because heat rises, so we're gon na do the top one.

So that way we don't unnecessarily heat up the valve, we'll do the bottom, one laughs. Sometimes, when you're working with critical parts you got to do the opposite of what you think. What's normal yeah watching everything I don't want to overheat parts and attention where my flame is going, don't know it's not time for what vowel and inspect the well before I cool to Joey. Remember you usually don't want to cool a joint, but on a sensitive part like an expansion valve you kind of have to so we're gon na inspect my weld make sure I got all the way around.

I think I got it once, but I don't like I don't like realigning a torch for an expansion of but positive, so we're gon na hit this guy real quick. I don't even need solder, that's how I have to take, because I'm not heating it up again. Yeah we're good yeah again, that's such a small valve, it's almost impossible to cool with the wet towel, all your brazing, even the heat compound stuff, it's so small! It's not really gon na fit in there. It's gon na be a pain in the butt.

So it is what it is next thing we're doing a pressure test. Unfortunately, it's really hard to get a suction line. Filter dryer in here I mean I might be able to fit one back in here, but good luck changing it out. So I think we're gon na fly without the suction line.

Filter dryer I've got a high acid liquid line dryer, so we're gon na do pressure test and pull a good vacuum and then we'll just keep an eye on the dryer, the liquid line, dryer, making sure it doesn't restrict again, because this is a burnout. Usually, you want to put a suction line, filter dryer on there, but it's just really hard - and this is a 6-ton compressor, so to get the right size I needed to go with the I have it. It's a 30 cubic inch inch and 1/8 line size and now actually that's not even the right size either, because no that's only for a 5-time, but all right. Uh - probably just put this one on there, but still getting that in there's really hard.

So I think we're gon na roll without it okay, so we passed the pressure test, I'm just letting the nitrogen out right now and then we're gon na get ready to do our evacuation and also, if I didn't already show it the entire time. I was changing. The compressor and the txb I was purging with nitrogen, so try to eliminate some of its nastiness, so we're gon na have to vacuum. On now, okay, we went ahead and put it on vacuum and took a lunch, we're actually in decay right now.

That comes done, but we're at 337 microns and slowly rising, but the decayed graph is just a slow arc and it's leveling out right now. So we're gon na call this a good vacuum and we're gon na go ahead and get this second stage charged up and then we'll check the charge on the first stage once we're done with that. So what we're doing right now we're still under a vacuum. So you can see on my vacuum gauge you're still under 500 microns and we're gon na go ahead and purge up until this point right here go ahead and crack that there you go turn it off.

Okay, now we're just going to purge now, go right here and purge right here: okay and then now that's the best way to get all the air out of the lines. Okay, so now we're not going to introduce air when we do the two hose vacuum. That's the best way to purge all the air from the lines and when I did vacuum two I had these things cracks not all the way up, and not all that would close. That way.

It was pulling from that little air pocket inside the vacuum for removal tool. So now we're going to go ahead and introduce the charge through the high side. We're gon na make sure we're zeroed out we're going to go and open up our high side. Gage.

All the way and we're gon na go ahead and open up our high side and then open up our low side. We're gon na pay attention. It's now, adding it on the high side and we're going to go and open up our low side. So the pressure comes back and we're at a high pressure, so we can go ahead and take off our micron gauge.

Now. This micron gauge is rated for high pressure, so we're good to go with that. Cap on was and we're charging now so we're just going to charge it to the full 14 pounds. Eight ounces - and this is using the field fees, Wireless scale with the SMAN 480, and it reads the scale right on there.

So I'm going to clean up our messes and we're going to give this condenser coil a cleaning because, as you can see, it's pretty darn dirty inside here - and this is the one I've shown before it's like right up against the wall, so we're gon na give This guy cleaning on this here too, okay, so we are all finished up for today. We will end up coming back to do a follow-up everything's running. We went in and popped off the charge on the second stage. I still have to come back with a fan cycle control for the second stage, because that was leaking, so we bypassed it, though the night we cleaned up, we cleaned out the condenser clean the roof off.

No more so we're good to go okay. So we return to follow up today on the SE C, and the first thing we're going to do is check the temperature drop across the liquid dryer. I've got my temperature clamps on each side of it, and essentially we have pretty much no temperature difference across the liquid dryer. Okay, I don't have pressure ports by we're good okay, so I don't see a restriction in the dryer.

Now we're gon na go in apply gauges, and I also brought my new fan cycle switch, so we're looking. Okay on this circuit, my suction pressure is a little bit on the low side, but everything else is looking good and my super heats right about where it should be. So I don't want to add any more gas. Certainly, we could have a little bit of an airflow problem, but this isn't really anything to mess with too much we're looking good on this guy.

So this is the compressor we replaced. It's looking good we're gon na go check out the other one, so something I didn't catch and then I'm I was just sitting there looking at right now. This is my first stage now, but look at my supply air temp, three seven degrees, that's way too cold at 37 degrees supply air tent, that's way too full so and the measure quick app is estimating. My air flow is being very low too, so it makes me wonder if we have an air flow problem and that would explain the lower suction pressure too.

So we're gon na go downstairs and take a look at some things. I mean this is nothing different. We're gon na make sure we don't have any obvious problems with ductwork or anything like that. I've got the economizer damper closed.

If we want to know actually what we could do, I could open up the economizer dam for a hundred percent and, let's see if our airflow problems are solved. If our airflow problems are solved, then it would explain possibly a return air problem. So let's see we're gon na, let it modulate right now and then we'll go downstairs and check everything out. Okay, so my economizers completely closed off and we're pulling a hundred percent outside air now and notice.

My suction pressure dropped even more, and what that's telling me is: is that there's not enough return air in the economizer damper to supply this unit with the proper airflow. So we're going to go downstairs and look and see. What's going on we're gon na go to close the economizer backdrop. This one just sounds a little point, ometer right, so dr.

Bob set that back there and then we're gon na go inspect the return, air and supply our girls downstairs and see what we can see all right. So here's our problem. This is a 12 inch supply girl and it's throttled down. They have a shutdown.

You can hear the air moving, the dress, here's another 12 inch. They have it shut down and then they're running three of these 14s so 314 to 12s, a 10 and then to 6 inches, and this is for a 12 time, rtu unit, so they're running low supply air flow on this unit. So we are running a high total external static pressure, so we're running - let's see 0.91 on this point: nine: nine on the supply and 0.30 on the return. So we've all got almost one inch of static pressure just on the supply side.

So yeah - and I mean this just confirms what I already assumed is that we've got an airflow problem and that's what's causing. Now. I don't know if that's what caused the compressor to go bad, but so this is the reality of doing restaurant HVAC, just like in residential. Very rarely is the ductwork designed properly.

You can already tell there's something going on because this building was brand new, but they they use an existing roof platform. I shouldn't say with brand new: there was a restaurant here before they completely demoed the inside, but they used the same roof penetrations from the old rtu units. So you have a curb adapter. You know on a new unit, which already tells you something and curb adapters are horrible for air flow, as it is add that this is a pretty short curb, adapter, so they're making a pretty strong transition.

If you understand that so basically right in here, they're gon na be like really quick, you know like or or even going like this down or something so anyways from the looks of these roof platforms. I bet you anything that this used to be an old train system as what I'm thinking an old train system is what was here before, and they probably just use the existing penetrations. I know they did new ductwork, but they didn't do the ductwork right. So this is just one of those things that happens in restaurants.

You know I'll bring this up to the customer, but they're not going to fix it. So I guarantee it once they get a mechanical contractor in here to fix all this. This isn't something that we would do. They've also got exhaust fan problems, so I don't get into that much construction.

I just like to tell people it's wrong, but yeah, so that's it. So it is gon na be what it is I'll make sure to make. Some notes for the next guy so that way someone doesn't have to go through all the work that I did to see that we've got airflow issues. Okay, so I'm gon na go on a little rant here here in California, we have a energy efficiency code called title 24 and essentially title 24 is not bad in its essence, it's there to make sure that we do our job right.

It's there to make sure that our units actually provide the airflow that we say they're going to provide it's there to make sure that we actually check the refrigerant charge properly. It's there to make sure that we do our jobs right. Okay, what's interesting is that this building had to pass all the title 24 code requirements, but yet I've got a kitchen a/c that has undersized supply air ducts. This big exhaust fan right here.

The ductwork is too long. It has a really high static pressure reading on it. The make-up air unit right here doesn't supply enough air we've done an airflow calculation on this building. We've had the manufacturer, captive air come out, and I, between myself and the technician we measured the air flow for the building.

We measured the pull on the exhaust fans. We did everything. As you can see, I've got static pressure, poles right there, where I measured static pressure and we found that that fan doesn't have enough strength to pull. It's like pulling a golf ball through a garden hose basically, okay.

So this kitchen has heat problems, but my question is: if this building passed title 24 are actually not. If how did this pass title 24 code requirements for air flow? How did this pass? The hers raters tests, majority of the buildings and I hate to lump everybody into one big picture of a majority of the jobs that I see that actually get air flow tested. Don't really work right! Okay, you know I hate to say this, but we're not doing our jobs right. The third party, hers Raiders, aren't doing their jobs right.

It's not just them. It's us too, we're not doing our jobs right. Engineers aren't sizing these buildings right, and this isn't just this. Restaurant - this is almost every restaurant I go to almost every restaurant I go to.

I find that we have airflow problems with packaged units anytime. You use an adapter curve on a packaged unit. You're gon na have airflow problems already. I just think it's kind of crazy.

We passed these laws to make us. You know to make sure that we're doing our jobs right and then we find a way to circumvent those laws because rumor I've heard through the grapevine is, you know the hers. Raters will pass you I'm not saying everyone. Does this but guys this building had to go through title 24 acceptance, testing and or whatever you call that stuff right? This had to pass all those codes and obviously someone didn't do their job.

So who was it? Was it the engineer who didn't size? The ductwork right was it the contractor who didn't say something when he was installing the ductwork. Was it the third-party verification company that verified that all those people did their jobs right? All three of those people failed on this job, and this is a typical restaurant in California. I I'd even argue to say this is a typical restaurant in the United States. We've got a problem here.

I don't know, people are just ignoring it nobody's talking about it. I mean I've been doing this for 15 years, something like that, and this is nothing new. This has always been like this kind of crazy to think about that. Huh.