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Eric Mele investigates several different issues with a restaurant's HVAC/R equipment, including an inefficient A/C compressor and a failed fan motor on a refrigerator.
The readings indicate that the suction pressure is high, around 152 PSI, with an 80-degree return. The temperature split is only 10 degrees, and the unit is running too warm with low subcooling.
When Eric pumps the charge down, he notices that his meter stalls out a bit. Then, he shuts off the blower and checks the suction line temperature. The suction line temperature rises past 91 degrees, meaning that hot gas is leaking back through the compressor. The data affirms Eric's suspicion of an inefficient compressor.
Upon further inspection, Eric notices that the unit has an aftermarket fan motor, which may have damaged the compressor and contributed to the inefficiency that Eric is currently investigating. When running the unit without the blower fan, the suction pressure fails to drop as quickly as usual. So, the compressor is the primary issue, and replacement is necessary.
Eric also inspects another small unit with filthy coils and a fan that won't spin. However, the compressor appears to pump normally. In this case, Eric replaces the fan motor and cleans the system. (As always, he makes sure the motor spins in the correct direction.) None of the bolts fit, however, meaning that Eric must use a set of customized screws. He doesn't put too many in all at once, as he wants to make sure the motor works and spins the right way first.
Once Eric was sure that the fan motor worked as it should, he used a Dremel to customize the remaining screws and mount the motor correctly. He also redoes some wiring and sees if the unit can make temperature. He runs the unit in defrost and checks the amperage as the unit comes out of defrost. The relay appears to draw high amperage; upon further inspection, the relay appears to be working, but Eric still takes the safe route and replaces the start gear.
The belt also has an issue; the belt is loose and runs counterclockwise. Eric replaces the belt, tightens it appropriately, and ensures that it spins in the proper direction. He props the motor up to get the correct belt tension, but the problem is bigger than that; the entire fixture will need replacement.
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Hi, this is eric with calo services in hvac school and today, we've got this unit here. It's got a slightly inefficient compressor and we'll take a look at the readings and how we determine that. These are the readings the units running right now and what is your indoor temperature, 81 81, so that doesn't look too bad at the moment before we had this thing running about 150 160 suction pressure, and it's probably going to come back up to that because before We started recording, i was running it with the blower off just to see how far it would pull down, and it was not very far so we'll let it stabilize and then show how we diagnosed the compressor was inefficient. So here's more like what we're running at with a 80 degree return it's running too warm and it only has a 10 degree split.

So i know the sub cooling looks a little low, but we've got enough liquid to form a diagnosis, so we're going to pump this unit down watch first of all how long it takes now we're never able to get it much past here. It just kind of sits in this range, no matter how long we let it sit and it never makes the bypass sound and goes way up. So in this application we have a small enough charge that we can pump it down without having that happen, but it should be at least either bypassing or pumping down a lot further, and it just stalls out right about here and we can look at our liquid Line and see it's not expanding, we don't have anything leaking by through the valve, so we're going to go ahead and shut it off here and show the next test. So if you look we're raising slightly, but one thing we're going to check out is our suction line, temperature close to the compressor so we'll move.

This fan out of the way put that there and now we're going to watch the suction line temperature. It's already 91 degrees, so we got the suction line, clamp there and we've got the suction line, temperature of 91 degrees, and you see how it's raising pretty quickly. So that means we are leaking hot gas back through this compressor, either through the mechanical bypass or the or the scroll itself. It's probably coming through the bypass, but i've not dissected them either way in the field.

You're not doing anything about that you're replacing the compressor. Now you can see this thing: has an aftermarket fan motor installed, so that could have caused damage to this compressor at some point in order to cause this problem - and you see our suction pressure keeps climbing, as well as our suction line temperature. So another thing we're going to show is we're going to run this unit without the blower fan, we're going to shut that off at the thermostat and hold the contactor in, because it's just the easiest way. This is an attic unit.

We're going to wait three minutes for that fan to shut off and show that the suction pressure doesn't really drop down like you'd expect. So that's really the last test to try and, as you can see, my liquid line is 81 degrees. If this valve was leaking by, that would be getting colder there colder and colder and you'd know that you had a problem there. In this case we've got it narrowed down.

These compressors are kind of known for that, so our contactor pulled out. It is 10 16. We're gon na wait like four minutes four or five minutes and then run it with no blower. So right now, probes are back.

We've waited it's 10 21 contactors not pulled in we've got no blower running inside, so this is no blower. Suction pressure looks good with no blower fan running now. If you've done this on a properly working unit, it drops really fast typically - and i know these are all kind of ambiguous descriptions, but it's the best. I got not really dropping not really getting below freezing the way it should with no blower see we've been running for about two minutes now and we're still running pretty safe pressures, but no blower fan super heat's kind of low, but it's not nothing.

Finally, getting to the freezing point, shutting it down: that's pretty conclusive. For me, this machine is going to have to get a new compressor got another little unit to look at here. Condenser fan is not running, i have a replacement, but i want to make sure that the compressor pumps before i do any of that. So, let's have a look, and yes, this thing has seen some better days.

The coil is pretty nasty. The fan, even if i hand start it plugged in it, won't spin it's a rat's nest that i haven't taken apart yet, but i pretty sure at this point we got a fan. Motor looks like it's pumping, that's good. This motor is trying to spin and the compressor looks like it pumps good, so we'll give it a try, see if it runs clean out that coil not sure which gas this is.

The evaporator is not running right. Now i have it unplugged, i'm just plugging the condensing unit directly to a cord. That's the normal wick from the unit see what we got here. These screws are pretty old; only one of them is a hex.

The rest of them are domed slotted screws. One got this multi-application replacement motor, that's what i have on the truck any other accessories really clockwise. I think this is the right rotation. Clockwise shaft end as far as o s e whatever that means.

So this might not be the right motor. The old one says: clockwise rotation arrow on this thing doesn't really say: rotation, clockwise ose - and this says it is clockwise. So hopefully it spins the right way right. That would be nice blade closer to the condenser.

Now, there's nothing guiding the air through this condenser, except for the condensing unit being in the cavity it's in. Unless that shroud was just lost to time. This thing probably came with new screws and i'm just doing it the hard way, but the old motor here it says clockwise this says clockwise ose. So is that the right direction? I guess we find out right opposite shaft, and i mean i know they're just weird how they do these, so this might be a giant waste of time.

Uh he's not going all the way in yet these are stopping. So i guess hopefully the motor comes with shorter bolts, and these look the same length to me. Yeah you'd think it would come with the with the right length. Bolts.

Then they're going to give you all these bolts they're, all stopping short. The old bolts are too long as well. It's really odd. What do they expect you to mount this to cool? You have to waste more time.

It's all the further. It goes so stupid. My screw cutter is not working because these pliers have a screw cutter. It's a pain in the butt, but all right, i guess it's not the right thread pitch.

Oh, this is just going great yeah. I don't know if i have washers small enough all these the same shaft size i feel like this should be the right size, but it's not fun fun. Why you do me like this nidek motor corporation? What i'm going to do before we get too far along is one screw goes all the way in tight, so that'll hold it, and this screw will go in partially, so it'll hold it from rotating and let's see, if it even spins the way it's supposed to Spin, i think this is a replacement yeah. This is a replacement for the single hole fan blade, but i think this one has the four holes will line up so compressor pumps, though i know i get more and more disappointed when stuff works on this unit, which is probably the opposite of the reaction.

I should be having, but i'm just like man, i just don't want to fix this thing. I'm just like please be flat and it had gas and then i'm like okay compressor, please don't pump, and it does maybe that's the wrong attitude to have. But this thing's a piece of junk in my opinion and should be replaced, i'm not going to put too many bolts into it until we establish that it actually works, because the whole coil is going to have to need cleaning anyway. The tape and the wire nut combination - everybody's favorite, oh no, going back from cutting the plug, it's a very short cord.

It has huh literally got to put a cable tie on it just to test it, so it doesn't chop all right, let's see if it explodes and it spins the right way. Look at that airflow's going that way. That's unfortunate! That means we got to keep fixing it. Do you see a path to get this thing out of here the magic of a dremel and a cutoff wheel? I made these screws shorter for the fan motor.

We cleaned out the coil cleaning off the blade. Since this thing now is a known running unit, gon na scrape that blade clean with a brush and put this all back together and slide it in, we got it barely outside the door enough to be able to clean it without making a mess in the kitchen Which is always nice and i just didn't - have any washers or anything else, so five minutes in a dremel. Those things will save you so much time if you've got one on your truck, so i'm gon na get this all buttoned up and let it run for a while and move on to some of the other broken stuff here see if it comes to temp all Right so this unit's back together, we had some wiring issues going on with it had to redo the cord. This plug both grounds were broken off and the chassis was hot because there was a wire pinched, no big deal new cord new end, all the way back to the unit and it's running we'll see if it pulls down a temp but there's another one to look At in the meantime, come back to this in a minute all right now we got this true freezer and the problem is pretty obvious, melted, wire, so we'll reconnect and see what happens.

Probably a bad relay, probably stuck so we have all the wiring redone. I have it in defrost, i had to pull the x terminal to get it to stay, but i'm going to want to put an amp clamp on this plug it back in and then take it out of defrost sorry trying to find it with the camera. I don't know how easy it is to see, but i only have about an hour of cooling and then a whole bunch of defrost reason being that this is over amping. When i crank the timer out of defrost horribly, i want it to shut off again, so i'll switch.

It back real, quick to all those off points. I have because i have no easy access to a disconnect. The plug is behind the unit and it would be take me too long to get to it. Go ahead and put this molex connection back together.

Clipped in and, let's see what happens, it looks like the relay is not releasing it's drawing way too high amps. It's like an 18 gauge wire. I'm gon na shut this thing down so there's my defrost. I tried banging on the relay.

It's probably toast, let's check the amps on this, but i'm guessing it's not. 11. hold low dams. 13.2.

Maybe that's the whole machine. It's interesting that it would be done with such small wire. Let me see if i could get in there and look at this compressor it's down there and i set the camera down. So it's saying 9.7 rla 27, and it is overloaded right now.

So i'm guessing it is working, but i'm still going to replace this start here. These wires are awfully small, see what happens so we have an issue with this and it's not just the fact that it's a loose belt. I know how easy it is to tell from the video, but it's running counter-clockwise and it needs to spin clockwise plus it needs a new belt all right. So now we're spinning the right way got the motor propped up to get belt tension, but this whole fixture just needs replaced, i'm not even gon na mess with it anymore.

That's all for this one thanks for watching our video. If you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is far more than a youtube channel. You can find out more by going to, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing.

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37 thoughts on “Multiple restaurant ac issues diagnosed”
  1. Avataaar/Circle Created with python_avatars jettelo says:

    When a compressor or fan has the paint off of it. It won't last much longer

  2. Avataaar/Circle Created with python_avatars Eddie Gomez says:

    When you’re pumping it down are you pumping the refrigerant back into the condenser unit itself. Do you close the liquid line valve completely and hold the contact or button in so the Freon pumps into it through the suction side? I want to know because this is how I’m being taught.

  3. Avataaar/Circle Created with python_avatars Ashton Lanier says:

    At least all your skids pulled out. It seems like every refrigeration call I get, they never do 😂 Are you in Kanata ?

  4. Avataaar/Circle Created with python_avatars ruben guzman says:

    Just curious on the temperature rise on the suction line your testing ,how do you know its not heat transfer from the compressor to the copper line causing the heat rise?

  5. Avataaar/Circle Created with python_avatars Sparky Tech says:

    LOL I get jobs like this all the time. because they don't do any maintenance on anything they run everything to the ground.

  6. Avataaar/Circle Created with python_avatars OthmanEmpire says:

    Thanks for the video =)

  7. Avataaar/Circle Created with python_avatars Ronald Clark says:

    Musta had alota calls.
    Got everything running.
    Lots of follow up.

  8. Avataaar/Circle Created with python_avatars HVAC1 says:

    Run that motor before you mount it to check for rotation.

  9. Avataaar/Circle Created with python_avatars Tom Walker says:

    I wouldn't want to eat there. NASTY, Nasty, Nasty.

  10. Avataaar/Circle Created with python_avatars Esteban Christino Gallardo says:

    You have a Face ID love to punch but I just concede you make a good tech.

  11. Avataaar/Circle Created with python_avatars Ted Lahm says:

    Jumping around on the description.

  12. Avataaar/Circle Created with python_avatars B. K. White says:

    Damn. I'm confused. So isn't that indicative of a failed metering device if the system doesn't pump down without the indoor fan running. Assuming it's a txv at the evaporator.. & what about a maintenance first?

  13. Avataaar/Circle Created with python_avatars RJ_Make says:

    Tech. Life

  14. Avataaar/Circle Created with python_avatars snapdragon 805 says:

    Really good video. Please make more of these videos. I love how everything is straight to the point and not talking so much and going off track.

  15. Avataaar/Circle Created with python_avatars Ronald Toledo says:

    Great video ! I also found interesting the socket on your phone being magnetic, what brand is the socket you have on your phone ? I need one of those! Thanks

  16. Avataaar/Circle Created with python_avatars Jerry Sarabia says:

    Im in hvacr school and it helps to watch these videos after a lab where I feel like watching these videos I can go back to the lab and slow things down and grasp more of an understanding Thxs man Are you in Barrhaven ?

  17. Avataaar/Circle Created with python_avatars gregmac19 says:

    Did you really try to blame the issue on an aftermarket fan motor?

  18. Avataaar/Circle Created with python_avatars Wayne Costanza says:

    Very good video, more please!

  19. Avataaar/Circle Created with python_avatars raymond Moore says:

    As rusty as the top of that compressor is, the fan may very have caused this issue. That compressor head got very hot over time.

  20. Avataaar/Circle Created with python_avatars Eassyheat/ Cooling says:

    😃 I know the feeling of an over due replacement!
    Thanks for the video!
    Stay safe.
    Retired (werk'n)keyboard super tech. Wear your safety glasses!

  21. Avataaar/Circle Created with python_avatars Tyson Rojas says:

    Right off the back the comp bad look at discoloration of the top of compressor mean been running high liquid line temps which could be early sign of valves going bad

  22. Avataaar/Circle Created with python_avatars CeeCee The Cat says:

    Oh I love Eric😺

  23. Avataaar/Circle Created with python_avatars Paul Rozinski says:

    Gee I wonder how much spoiled food this restaurant served before calling for service. I’m sure techs all have horror (kitchen) stories to tell.🤢 Service area Orleans??

  24. Avataaar/Circle Created with python_avatars Philip Wall says:

    Great diagnosis on the first split system, you don't see in efficient compressors everyday.GREAT JOB!

  25. Avataaar/Circle Created with python_avatars HVACR Ice Cream Guy says:

    L5411 Packard

  26. Avataaar/Circle Created with python_avatars Mitchell Armyguy says:

    It's crazy how nasty hvac equipment gets in a restaurant. Cleaned some rtus the other day at a taco place all units were pretty close to the kitchen exhaust fans and all of them were completely caked in dust and oil vapor. Crazy shit is they only do maintenance once every 6 months. Evaps had oily residue all over them like you see on a kitchen hood. Of course the condensers had blankets on them. The worst unit had a brand new condenser next too it like they would rather buy units than increase the maintenance intervals.

  27. Avataaar/Circle Created with python_avatars Joe Shearer says:

    Do you the 13a on the nameplate was for the defrost heaters? That's how it is on regular house refrigerator

  28. Avataaar/Circle Created with python_avatars Jaime Gonzalez says:

    What about just cleaning the evaporator coil first before anything!?

  29. Avataaar/Circle Created with python_avatars Mark Bell says:

    Everyone loves a good shit show.😂😂😂😂

  30. Avataaar/Circle Created with python_avatars Durian Den says:

    What tool have ? Blootot gauge?? Are you in Nepean ?

  31. Avataaar/Circle Created with python_avatars Joe Shearer says:

    I don't think the temperature clamp test is a good one with a scroll. For one the motor windings very close proximity and there is a internal check valve that will work to stop the bypass in off cycle

  32. Avataaar/Circle Created with python_avatars marty maness says:

    Does a scroll compressor have a discharge valve?

  33. Avataaar/Circle Created with python_avatars James T says:

    Super tech, get it!

  34. Avataaar/Circle Created with python_avatars Waylon Wells says:


  35. Avataaar/Circle Created with python_avatars Dark says:

    Im in hvacr school rn and it’s really cool working on little things in class and seeing how it all comes together like in this vid

  36. Avataaar/Circle Created with python_avatars ENOVA Electronics & Service says:

    Good job bro Service area Barrhaven??

  37. Avataaar/Circle Created with python_avatars Michael Taurus says:

    dont you love how fan motors almost never come with new hardware 🙃 Service area Ottawa??

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