MULTIPLEX SYSTEM IS COMPLETELY DOWN

This was a call for a multiplex system that controls their bar reach ins and their waitress reach in that was completely down.
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[@ElmerCat]

The concept of a "multiplex" system where one compressor cools multiple refrigerators brings back childhood memories of the most fascinating refrigeration system I've ever known. Known as "The Ammonia Machine", it cooled various walk-in coolers for meat, vegetables, and beer; several reach-in boxes in the main and banquet kitchens; multiple back-bar/underbar coolers - and it also made all the ice used in the hotel's bars and restaurants! Instead of refrigerant being circulated to all those locations throughout the hotel, the ammonia machine chilled a brine solution down to below freezing, and the brine was pumped through cork-insulated pipes. Built in 1926, the hotel's mechanical systems were quite sophisticated for their time, but by the 1960's many things were breaking down. Because it affected so many things, my father was frequently getting called in the middle of the night by someone saying: "Jack, the ammonia machine is broken!". So ultimately, the ammonia machine was shut down and replaced by individual Freon-based condensing units. After then, my father would get called in the middle of the night by someone saying: "Jack, [one of the many coolers and refrigerators] is broken!". Still, the old ammonia plant with its giant belt-driven compressor remained in place for years thereafter. As a little boy, it was something I spent endless hours just marveling at!

[@alexanderkupke920]

I wonder if they still use ammonia for anything new except large industrial applications. I think even ice rinks lately switched over to some sort of glycol coolers (where of course the glycol replaces the brine not the ammonia). I guess not, considering how nasty an ammonia leak can be.

[@steveH384]

Was this at Biltmore?

[@ElmerCat]

@@alexanderkupke920 Cheap and extremely efficient, ammonia is the most commonly used refrigerant worldwide for large commercial applications. It is the only refrigerant with a density less than one. Its latent capability at 5° F evaporator temperature is 565 Btu per pound, compared to 69 Btu for R-22. As a result, much less energy is needed by an ammonia machine to achieve the same amount of refrigeration as other systems. It is the most efficient refrigerant available.

[@ElmerCat]

@@steveH384 It was The Hendrick Hudson Hotel in Troy, New York. The building still stands and was converted to apartments, with retail food and beverage establishments at street level. I'm sure most of its original mechanical systems have been replaced, though I wonder if the old, derelict ammonia machine might still be there deep in the basement.

[@douro20]

There's actually a company called Multiplex which deals in refrigeration but what they are best known for are systems for cold carbonation, where the water going into a drink fountain is cooled down to near freezing before being carbonated. I've seen a few of their chiller-carbonators and they are quite impressive in their complexity.

[@pedroromero6224]

These are the type of videos i like i be doing a lot of restaurant refrigeration here up north and man its crazy especially them cheesecake factories lol. But really parallel rack systems. Isolated rack systems. And those multiplex even flexpack units. Seeing any of thats really makes me a better tech. Thanks for the gems

[@patriknilsson2175]

I'm getting nightmares of this way filling up with leaky components... in sweden we do have to find the leaks and fix those before filling up the system again. If there's a leaky component that's have to been ordered we are allowed to fill up so it's functionable, but it has to be just a small leak, if a big leak fix it in a good way if possible so it will last until the new components arrive.

[@jasonjohnsonHVAC]

We are allowed to add refrigerant as many times as you want, if the system holds less than 50lb ( 23 kilos ). Not saying thats the best way....just the way it is

[@Augdogfrogslog]

JB weld fixes all leaks Source: trust me bro

[@MegaDysart]

Sorry man. I know things are always perfect in Europe but here in lawless scary America most businesses don't have time to wait for leak finding and repairs, they have to have equipment operating as fast as possible and sometimes a "gas and go" is all they're gonna pay for, even if they know full well they'll be paying for more refrigerant later on top of the repairs necessary.

[@xARMM4G3D0Nx]

@@MegaDysart I'm pretty sure its a environmental and climate thing. If you just keep filling a leaking system you keep venting gas with pretty high GWP-Values to atmosphere and that is something that europe just doesn't want and will thereby prohibit by law. You know Paris climate agreement and stuff.

[@joakimjrgensen4329]

Yes it is a climate thing here in the EU. You aren't allow to anything without finding the leak. You can of course fill it up if you are returning and fixing the leak as soon as possible, but you can't just keep filling it up without fixing it.

[@mypindiwala]

Best explains headmaster valve function on hand.I bet no other video on this topic which explains with that simple and ease. Thanks.

[@StrengthCircusDD]

I have a huge multiplex rack on a casino buffet that took me forever to find all the leaks! I haven’t heard from them in a few months which surprises me. Side note: so many customers don’t believe acidic products will eat through coils rapidly. I always warm them to keep things covered and away from fans and coils if it must be chilled.

[@dragonrider4253]

I love how informative your videos are. I heard a vacuum cleaner in the background. That reminds me I need to vacuum today.

[@EnderMalcolm]

So new it didn't even show up in the feed yet. Can't wait to see what's up with it!

[@MattTrevett]

Excellent explanations. For beginners this is a really good video since you don't 100% assume a base level of knowledge. Thanks for posting!

[@jasonjohnsonHVAC]

Fantastic job Chris. The way you go through a call....in my opinion is the way we all should do it. Treat it like its your own or your mother's system. Being thorough and never stopping till the end. I have found countless multiple leaks over the years....as a matter of fact the job im on right now....guy found leaking valves ( someone else was here for leak search, i was here for repair)....replaced them and pressure tested.....dropped 10 psi within 45 minutes.....there is another leak. On a different note....the Stratus doesn't seem to be affected from moving around too fast on high sensitivity mode. Not trashing the FP....it does seem like a great detector. Keep the awesome videos coming, we like them and your channel

[@Bobherry]

CHRIS WHEN ARE YOU GOING TO DO MORE WORK ON YOUR PERSONAL HOME PROJECT I WAS EXCITED TO WATCH THAT.

[@hsvhel]

I'm not even in this sector and i find you so thorough!!!!

[@colinstu]

I'm happy to know there's a Queen valve.

[@russo5196]

Good explanations, I have always used the 1# for every HP of compressor for winter charge. That is in line if you didn't have factory charts. Most guys miss the winter charge when repairing a leak in summer!

[@pavelhazdra6498]

I work in a completely different field, but I love your videos because of your complex way of thinking. Looking forward for another amazing video!

[@stevencossaboon3237]

Good afternoon Chris. Another great video. Thank you for the learning experience.

[@Threee_Eyez]

I used to install Multiplex's all the time kinda miss those days.

[@kennethlobo4420]

Thanks for giving us such detailed explanation. God Bless.

[@elijahtalbot5288]

Love the videos I watched you when I was in hospital

[@steveH384]

I am not even sold on the coatings being worth a damn, ive replaced just as many coated as non coated, but hard to judge perspective on that.

[@MrAdamd83]

Thank you buddy for doing this video and explaining the service call down to nuts and bolts good job I love gaining knowledge from these videos you do!

[@trevorjudd516]

Hey Mate. I have this observation about the way modern condensing units are made that drives me nuts. I'm a second generation refrigeration specialist and will have been in the industry since 3rd December 1972 so will be 50 years very soon. (between Dad and I, it'll be over a century in the industry). I was always taught, by Dad and trade school, that the sight glass should always be after the drier and facing UP. The flow from bottom to top, as it gives a far better indication when the unit is the slightest bit short of refrigerant. You can actually see a bubble rising rather than a flash. We all know that sight glasses on the horizontal plane are a joke. We also understand that manufacturers will produce a unit with little regard for service techs and that was how the upturned feed began in the first place. To save 3 cents worth of copper. I have a challenge for you, as you're well associated with suppliers. Make 2 exact same units but one with bottom to top feeding sight glass and partially charge them.....exactly the same...and compare. You seem well connected and have a huge youtube following so it might be an interesting video. IF the theory is right....give me a shout out occasionally! Regards, Trev Judd. Australia

[@jeffreykubiak5126]

Great video thanks Chris!

[@edwarddapalmer]

Super informative and educational video. Thanks for the quality content 👍

[@skorpion1298]

Live stream of how you prep these Coils? :) that would be awesome!

[@Nba19980]

Thx this content is gold. I’m a new refrigeration tech.

[@Nba19980]

I’ll try to support ur channel

[@CHOMAHOMA]

I love the Ultrasonic leak detector because of the same reason: I want to kill the curiosity and find exactly where the leak(s) are coming from. It is very effective. It's expensive, but nothing escapes the detector.

[@johnwalker890]

Good job Chris.

[@jesusislord6773]

Hey Chris This is from a Bohn BCH0055LBACZ-RS-HRP Low Temp Outdoor Condensing Unit, under charging procedures in the manual: Head Pressure Systems- If you are charging the system by using a clear sight glass as an indication of proper charge the following must be considered. Check the condensing temperature. It must be above 105°F. If not, it will be necessary to reduce the amount of air going through the condenser from fans still running. Simply reduce the effective condenser face area to raise the discharge pressure above the equivalent 105°F condensing temperature and then proceed to charge to clear the sight glass. Adjust evaporator superheat at this time. Return to full condenser face area and allow the system to balance.

[@HVACRVIDEOS]

Those instructions would only apply if it did not have a head pressure control valve

[@jesusislord6773]

Yes true, just trying to show where the blocking of the condenser confusion can come from.

[@henryahmed]

@@HVACRVIDEOS Hi,. Writing from Canada here.Those instructions from Heatcraft are actually for flooded head pressure systems but I think they are incomplete. The following is taken from the IOM from REFPLUS (Canadian manufacturer). They provide a chart similar to the one you showed from Tecumseh. Heatcraft does not provide this chart though. "If the system is designed for winter operation (flooding valve type), check the condenser summer/winter refrigerant charge. Charge the system in summer operating condition with cycle fans off and block some of the condenser surface to simulate summer operating conditions (pressure and/or temperature) without condenser flooding. Recommended pressures and temperature are over 100ºF (38ºC) for 180 psig flooding valve or over 80ºF (26.7ºC) for 150 psig flooding valve. Once stabilized, add the difference of the winter/summer charge specified on the following refrigerant (R-448A) charge list, to the system. This should be sufficient to maintain the operating pressure during winter conditions (-30ºF (-35ºC))."

[@rockercover]

Interesting about what caused the coil leaks. I would have guessed vibration, shaking of the coil, creating the leaks. With the compressor on the roof, probably the in-unit coil is not vibrating / shaking enough to ruin it. Appreciate your angle on this issue! Agree about copper tubing, especially in water line applications, such as refrigerator ice cube makers, have seen the copper turn green and start leaking in places. (Electrolysis possibly)? Good evening...

[@alexanderkupke920]

With the copper you can see that it was acid based corrosion, as it did not turn green, but blue. But to be honest, within a cooler, I would never have considered any vapors, even from something as mild as dilluted vinegar or lemon juice as you find in the dressings, to be that corrosive. I only wonder why only that capillary tube from the valve corroded that way that much, but I guess the other copper just might have had some oil residue or oxidation on top preventing issues like with the coiled capillary tube. that might just have been too clean and thus unprotected.

[@justme5384]

Good evening

[@gordonkameda486]

Last time I had to fill one it was - 35°C( yah I'm Canadian), so I just cleared the sight glass

[@MattTrevett]

For whatever reason, condensate can be very corrosive. Might be worth adding a shield if you know that something is going to drip condensate.

[@amsoiltek]

I was just thinking the same thing, maybe some ABS sheets and maybe heat it shape it into a tent shape.

[@Starchface]

What must be happening is that the acidic compounds from the salad dressings (acetic acid (vinegar) and citric acid) are being blown around in the box and deposited in places like the evaporator. The expansion valve and lines are made with copper. I suspect that the condensation dripping from those surfaces contains traces of copper. Those copper ions and the additional moisture are accelerating the corrosive reaction.

[@qcsupport2594]

Yeah. But why don't heatcraft's engineers already do this or position the txv where it won't drip onto the coil?

[@HappilyHomicidalHooligan]

In the reach-in coils, can you add a 2-3 inch wide strip of stainless steel to sit on top of the coil and then wrap down the front of the coil to catch the condensation dripping off the Expansion Valve and then run across the stainless steel strip and drip into the bottom of the cabinet so it never touches the coil fins? Basically what I'm trying to ask is can you make a shield for the coil that sits under the valve to catch and divert the condensation that isn't so wide it blocks the airflow needed to cool the compartment?

[@JH-tc3yu]

Dang what a fantastic video

[@scottlaferriere4499]

Do all evaporators have to be calling in order to charge this up properly including the winter charge? Also surprised to see no oil on bottom of evaporator enclosure

[@dashcamandy2242]

I'm not surprised that acidic foods corrode coils. I'm more surprised that salad dressings (and the like) aren't COVERED when stored. I shouldn't be surprised, knowing firsthand how many food service employees are, but still... As a lowly Crew Member myself, I am well-known at work to be the one person flipping out over improperly stored/expired product. Like the other day, when I found in the sandwich station drawers Croissant Muffins, stored in the bin that two days prior I had tagged and thawed Turkey Sausage patties in, with my label still on it. It took several rewrites before I felt safe posting in Group Chat about the need to not cross-contaminate and to have food properly labeled in clean bins, no exceptions. The first few drafts would probably have gotten me fired for my, um, "assertive hot take" shall we say. We LITERALLY have our patrons' health in our hands, food safety is kinda a Big Deal. And I spoke to my Assistant Manager on Thursday, she's going to try and pull some strings so that we can order cleaning supplies, despite being $5,000 over our budget and having nothing to show of it. At least there's two of us that give a damn!

[@redtails]

With these kinds of multi-part systems, I wonder whether it makes sense to actually pump around the refrigerant instead of just pumping around brine or some other liquid solution... In big multi-storey office complexes and especially in hospitals / research hospitals, the coldrooms and aircons are just fed with ice water. I suppose it's a practicality thing, as there could be hundreds of "evaporators" spread across the building, each needing a slightly different heatpumping capacity. Minor leaks in the liquid wouldn't be a big issue, though minor leaks in refrigerant lines add up over-time until the system is empty as the one in this vid

[@BluesStraightFromTheHarp]

Its been 15 years, (or more) R-12 was still in use, R-22 the "newest replacement"...I miss it. Question, when charging the unit wouldn't you want to replace as much of the cover or use a broken down box to block off the top/side to simulate normal op conditions? As this would increase pressures? (You just went where I was about to go regarding over charging as I watching.) I never enjoyed resteraunts, grease covered everything, lol. Salad dressing being uncovered? Good call on not accidentaly vaccuming in particulates! Good stuff! Thank you for sharing!

[@ryancurtis2038]

Lol by the title I thought it was going to be about the multiplex system they have at mcdonalds for their soda equipment

[@FerroequinologistofColorado]

Probably a dumb question. How does salad dressing destroy a coil? Is it the vinegar that attacks and erodes the coil?

[@gordonrichardson2972]

The acetic acid in vinegar is volatile (and gives its tangy smell).

[@FerroequinologistofColorado]

@@gordonrichardson2972 ok. Thanks

[@mrbugenhagen3364]

Yep, pretty much anything acidic will destroy the coil. The newer ones especially because they are thinner walled pipes due to "better heat transfer rate" if you ask the manufacturer but more likely cost savings in production.

[@DjResR]

@@mrbugenhagen3364 It's both because heat has less material to travel through._

[@RodrigoRamirez-fc5hv]

I like how you explain things.

[@martyechols5780]

Man to know what you know on refrigeration

[@EoRdE6]

I feel like the power head is dripping condensation on the coil and causing deterioration...

[@rustynail2210]

Heat producing device. Translation roast it with your torch

[@F12255]

i dont do much refrigeration. any reason for a head pressure control valve as opposed to a fan cycle control?

[@joshuaobelenusable]

Hey Chris, did you catch that broken liqui-tite at the 15:16 mark?

[@Eddavids2]

Should spray them with Croil or some sort of oil undercoat lol

[@gbuss814]

I think I would stop putting refrigerant into the system after the sight glass was full until I find the leaks. Only because I'm lazy and don't want to recover the extra 4.4 pounds of refrigerant. Lol

[@throttlebottle5906]

who needs to measure winter charge, it will correct itself by blowing the plug 🤣🤣

[@douro20]

Do you know anything about Trane S8 systems? What I would like to know is if it is necessary for the system to be connected to the Internet to service it. I know that it is locked down so that only Trane people can do it.

[@quietone610]

@14:54 THERE's your problem! Mixing alcohols is BOUND to be trouble.

[@paulfickinger4740]

So where I work has a ColdZone system (ETHN-5 is a partial model #)with multiple compressors sharing a condenser each compressor runs its own evaps usually 1 evap in walk in freezers 2 in walk in coolers. Would that still be a multiplex setup? It's my first time working on em and your video really helped with my understanding of them!

[@dawsont933]

HA, got here early for once, great video as always!

[@robt9969]

I like your video

[@HappilyHomicidalHooligan]

And even if you DID know without any doubt it's the coldest day of the year, most Techs aren't Masochistic enough to go out into that cold and top off the Charge... 😄😁😆😅😂🤣

[@1555yodude]

would it be possible to move the txv to under the coil?

[@DanO181919]

How would you recommend charging a manitowoc ice machine with a remote condenser (w/ headmaster) The machine works when outside ambient is above 70 degrees and stops working when outside temps are below 70 degrees. It needs the extra / flooded charge for low ambient conditions, the evaps suction line temps shoots up when the head master by-passes. I’m thinking the only way is to recover the charge and weigh in factory charge. Was hoping there was another way. Thanks.

[@HVACRVIDEOS]

You have to recover the existing charge and weigh it back in, there is no other accurate way

[@DanO181919]

@@HVACRVIDEOS thank you. That’s what I was thinking. Much appreciated

[@1966jcar]

Too bad you can't put that expansion valve underneath The coil

[@mohammedhamideh1002]

What is a winters leak ?

[@D_Nice981]

Hey Chris Where can I find calculating the winter charge chart for this type of condensing unit?

[@HVACRVIDEOS]

Google Sprolan 90-30-1 and it will tell you how to calculate the flooded charge. Or in my case I found the install manual and was able to use the manufacturers chart

[@jayfowler4747]

Why do they not use a fan speed control instead of the head control valve?

[@patriknilsson2175]

Americans still are back in the 80's when it comes to electric couplings and refrigeration components 😉

[@kyle6597]

Can you tell me which model refrigerant detector you use? Also in resi hvac we rarely use them, mostly its dye and i hate it. Just wondering if you suggest those dectors more then dye and bubbles. For some reason my company never has much faith in those detectors.

[@FerralVideo]

He's using the Fieldpiece DR82 (mentions at 14:30).

[@kyle6597]

@@FerralVideo Thank you.

[@fleurdelune5240]

❤️

[@swampasssapper3643]

Would there be a way to re-plumb the evaporator so that power head and other things are below it. Seems like it dripping rusty stuff is what caused it to leak 🤷‍♂️ not a hvac tech excuse my potentially bad idea..

[@shine-cg9uf]

💪👍❄🇺🇸🙏 thanks

[@DanO181919]

What’s the Infrared camera you use

[@HVACRVIDEOS]

Flir one pro

[@DanO181919]

@@HVACRVIDEOS 👍

[@steveblake8766]

990 thumbs up

[@Lachlant1984]

Why is the leak detector making a strange buzzing noise? I presume it's a component within the leak detector, what component makes that noise?

[@quietone610]

Tiny piezo crystal that gets powered when the gas is detected.

[@numanmirza9584]

Sir what is the compressor rasio kindly explain in simple word's

[@numanmirza9584]

Only like not explain...???

[@oscarguzman9669]

i like the hat you. your sell

[@hvacr24]

full column of liquid :]

[@josephtramutola592]

Ultrasonic leak detector

[@sharnimassey4969]

4th comment

[@tonyking9235]

DO ENEY OF YOUR CUSTOMERS WATCH YOUR VIDEOS . IF THAY DID IM SHURE THAY WOULD GET A GOOD INSIGHT TO WHAT THERE SYSTEM HAVE TO COPE WITH . AND THERE FOR GIVE THEM THE CHANCE TO SEE HOW IMPORTANT IT IS TO AT LEAST CHEEK THAT THE SYSTEM IS NOT CLOCKING UP AND THAT BELTS AND NOT WORN OUT . I KNOW IN HARD TIMES THAY HAVE TO BALANCE THINGS . BUT ITS A FACT IF YOU DONT DO AT LEAST THE BASIC. IT WILL COST YOU BIG TIME COMPAIRD TO REGULAR MAINTENANCE.

[@brocwilliams7186]

Please don't tell us about the flooded charge everytime

[@youtubevideos7040]

First comment

[@youtubevideos7040]

Thank you so much

[@richardharmon874]

I never heard of a winter charge. You either charge the unit properly or you dont.its not like you take refrigerant out in spring and add in fall.stop saying winter charge i hate it.if you have to charge a unit in August at 99 degrees ambient and you know in December it will be -4 degrees you better add some more juice. Common sense. Stop saying winter charge.

[@HVACRVIDEOS]

Winter charge does not mean you remove It. Once you add the flooded charge and or the winter charge your good all year long

[@richardharmon874]

@@HVACRVIDEOS so why cant we just call it charging unit properly? Talk to me

[@richardharmon874]

@@HVACRVIDEOS i from new hampshire wich is probably alot cooler then your area. Around here it is common knowledge if you charging freezer in summer you should know in winter your headmaster is going to hold back your liquid and dump discharge gas in tank so you better juice that baby up.i try to put at least 75% of what my receiver tank size.but then again i am drunk

[@johnrider7826]

Why did you not add dye and use the light to detect leak?