Great video. Your point about the economizers was spot on with properly balancing the restaurant. One important concept in restaurant air balance you did not mention is balancing more makeup air in the customer area and less in the kitchen to draw kitchen odors, grease, and heat away from the clients. Keep the vids coming....great stuff

I clean kitchen exhaust hood systems for a living. That place looks like Chili’s. Cleaned dozens of those in NJ and PA area. Everyone of them had Melink bypassed. That system works well only on paper. Beam Sensors aren’t water tight. They get ruined all the time. No one opens them to wipe the lens. Small fans above the hood blow air through the sensor box - those die and no one notices. Vfd burn out often. Awesome videos. I subscribed. Looking forward to more exhaust fan and make up air vids.

Thanks, bro, great video. You gave us valuable real world troubleshooting scenarios and info on control panels. In this system what you could also do if client budget allows is put variable dampers in the kitchen RTUs OA dampers and tie them to a control panel with DP sensor input, so that it intakes only the required amount of FA at any time, depending on the working frequency of the kitchen hoods. This will result in more energy savings.

I learn more on an 11 minute video than in a year of doing routine field work.

Thank you! Lately, county inspectors have been pressured to get air balance in restaurants.

Thanks for mentioning the rooftop intake near sewer vent issue. Got me thinking of a site problem. The electrician byoassed the control relay to run exhaust fan 24/7 but probably the rooftop pulling sewer vent gas in

I had a customer that for years refused to install new make up air units so that his kitchen would feel comfortable for his employees and so that his restaurant would feel comfortable.. Few years ago he decided to get another company to install a 10t AC just for his kitchen.. I told I wouldn't do that , that it wouldn't solve anything. So anyways he got it done and $10k later still had same issues. I ended up disconnecting that ac the following summer, some people just don't get it

I have a customer with that exact layout, equipment, and problems ! It used to be an Italian restaurant but it will now be reopened as a sports bar. I am very worried that with the big crowds and of people they will have a lot of problems keeping up with coolings needs. Keep me posted on your results please . Awesome video !

I have absolutely no idea what you and everyone else in the comments is talking about, but it makes me feel smart watching these videos

This video is so informative. How in the heck could I've ever known that sewage ventilation is related to the building pressure. Like the bypassed VFDs in the video, I bypassed few years of experience and a giant pain in the neck with this video! XD

They may change their minds after they start getting the A/C bills to cool 100 % outside air

I've had to do this same thing with these Vfd"s . Ended up wiring in contactors with toggle switches mounted on face of hoods so they could shut them off vs throwing breaker. They don't like power surges at all ! Good job as always!

Great job. I been balancing for about 20 years. Very good shows you really understand a lot. Nice to see next time I work and I see that model I will remember your video. 👍🙏 I hope I get to see more videos I really liked it. I learned something about occ mode.

Wow. Kitchen grease hoods need dedicated makeup air provided around the perimeter of the hood to make them draw and operate properly. How is this place getting by with using the comfort heating and cooling units for make up air?? Huge draft will be set up that drags air across the food the cooks set up on the counter, which cools off the food. Sounds like a design nightmare. The dedicated makeup air units are usually tied into the exhaust fans to run any time the hood is on. The good ones provide heat and cooling as makeup air is supposed to be conditioned. Kitchen makeup air should not be provided by the comfort cooling system.

You’re the real deal! What came to mind was high head pressure but not the case! Just restricted air flow with the damper, filters and exhaust fans.

I had this same problem in one of my restaurant where the ac was pulling in sewage smell , we added a fresh air duct for the kitchen, Awesome video

Another great video, Chris. Thanks for posting.

Not in my realm of experience or expected need to know, but fascinating to learn anyway. Thanks for posting.

Great video Chris very informative I learn a lot from your videos commercial and residential 👍👍

Excellent diagnosis! Methodical, as always.

Thank you for posting this.

The cost is low for them VFD'S and pays for it self during A/c operating cost in the first 6 months.. With drawing O/a the cooling air dew point will be high & not comfortable ( humidity issues).

I swear I wonder my brother if you should go commercial but that is my uninformed opinion. Reach-ins and Mom's and Pop's are the trenches but you are definitely Graduate level. Love your videos.

Very well done 👍 thank you I always Lear allot from your videos thank you

Love your videos man

This video got me thinking. We've had some intermittent problems with sewer gas coming in our house for a while, mainly during the warmer season. The biggest cause was that someone had put a cap on the vent pipe that runs to the kitchen drains. But I'm also starting to wonder if the basement radon fan is causing some negative pressure as well. The house is over 100 years old and is pretty drafty, but maybe it's still not enough to self-balance?

Captiveaire hoods. Uses 80% of it own make-up air and only 20% of HVAC . Thank you for the video. It will held in the future. Only issue I have is humidity. Last guys turned the humid sensors off on 10ton unit because Delta-T was off. Units use heat in summer to help dry air. It just created a worse situation. Either customer thinks things are to expensive to fix or you get a screwball tech. Which is worse. Isn't vent pipe supposed to be 3ft above everything else? Multi speed motors are not available at

Thanks Chris, learning alot

Yep. Definitely a crappy situation lol. I didn’t even realize the old M1 boards had those economizer controls. We only have a few of them left in our market. The rest are M2 and M3.

Great info. brotha!👍🏼🤙🏼🤘🏼

Interesting and educational vid Bud ... Good info for the younguns'

I ran into a similar negative air pressure problem where I work only ours was with the updraft spray paint booth exhaust fan. They're so cheap where I work, a door has to be open every time the spray booth is used.

When I was working in the hotel as a maintenance supervisor, there were some guest rooms which had negative pressure problem. The Rooms were smelling sewage. The Chief engineer told to the mechanical supervisor to fill gaps with foam between the guest rooms and shaft where sewage pipes were passing. But still no effect. I entered the rooms and figured out fresh air dampers were closed or someone put towels in order to prevent slight blowing air sound. I explained to the chief engineer that what are negative and positive pressure. It took several years to get him to understand.

always interesting....

Omg Lennox🙄 good video good methodology

Good information thanks

Interesting video 👍

Good video! When you had the manometer tube going through the roof hatch did you just have the magnetic metal probe that comes with the meter dangling taking pressure that way or did you have something else on the end of it and how far down did you dangle it?

Flippin da switch to d set!

Great video Chris. That looks like the VFD system we had at a shoney's I just started. So are you just gonna adjust the pulleys and slow them down or do they not have them?

Ha, hate this problem. One of the Perkos I used to service always had this problem. Same deal.

times like this its best to just think positive

So glad I found this video. We have a sewer smell and an air balance issue at out restaurant. We called a company out and they sped up out MUA units which helped a little but they also told us thats the best they could do because the units are old, not sure what they means because they are in proper working condition. When the back kitchen door or roof hatch is opened, the air balance gets much better. I will look into the AC dampers also. Do you have any videos that how how to clean the MUA blower fans?

Raise the sewer vent pipe high up. Sewer gas is heavy and tracks to stuff below the parapet wall. Give the gas a chance to get blown away.

Do you have minimum outside air requirements? We have a % per m2 or per person whichever is greater. Also if there is no make up air for your exhaust system you are exhausting all your conditioned air out, it’s a wonder they haven’t had temperature issues during the weather extremes. Unless your power is very cheap the power cost should have a short pay back period on repairs or installation of a make up air system. Can be frustrating/difficult trying to explain things like this to customers. Good vid 👍👍

Whats with the high temp silico e at the bottom of exhaust .. interior?

Chris, in Chicago we keep kitchens under negative pressure. Dining is under positive pressure though. I wonder where did you measure that negative reading ? Kitchen or dining? Great videos thanks for sharing.

also, forgot to mention blocked or improper sewer vent sizing and "bad" neighbors causing large positive sewer line pressures! and partial clogged/restricted lines can cause enough positive when draining to push through traps, "plumbers" could easily miss things like that, without many years of experience ;) could also be wind direction change/lack of it from the exhausts being pulled back in via the "makeup" air, it really needs bright fella to figure it out, I'm betting you can :)

So this might explain why a supermarket in my area winds up with a seriously bad odour on occasion especially after rain

You could get a total cfm of negative from fans then size a dedicated pretreat.. high humidity issues out by you? If not could do a fresh air swamp cooler as a cheaper doas. Load calc on hoods to figure out max exhaust needed to see if you can lose some negative cfm(vfd probably oversized the output of exhaust so might get lucky if they did) by changing/adjusting pulleys. Erv/hrv might be a good idea.. not familiar with your location though. Sounds like any direction you go though customer is going to have to sign a decent size check. Hopefully it works out for you. These are the interesting calls for sure.. frustrating at 1st when you keep digging but rewarding when a plan comes together.

Hi, what is the acceptable pressure difference?

I just started with a testing and balancing company, I'm finding it difficult, but I've never done anything like this bbefore. how long does it take to get the hang of it.

The Shitter is Full!🤣

Wouldn't the efficiency savings outweigh the extra repair costs to the VFD's and brain? Sounds like a tough sell on the owner.

Isn't there a matched air makeup air handler integrated with the kitchen hood exhaust hood

Great video and information, does the dishwasher hood get tapped into that system?

Sewage smell? P trap? Restaurant applications definitely require slightly pos. Press. In dining area vs. Kitchen.

restroom exhaust not working, probably 1/2+ the sewer smell, followed by other comments on dry traps/bad primers or lack of traps, plumbing issue causing trap siphon. I forget at what negative pressure the traps will end up letting gasses in, but sees to me it's pretty high (many inches of water column)

By the way thanks for the suggestion of the broken drain line there was one thing that was suggested by someone else on the internet when I mentioned running things things moved are they said have you tried just running the heating system turns out it's an HVAC issue when the unit is running that's when we smell it when heating system is running first of all old system do furnace disconnect switch is like a Cutler-Hammer or something like that still in use and the thing is not 220 original 30 amp cartridge fuses probably like either oil-fired or possibly a coal furnace very big return air ducts more likely originally gravity feed may have been boosted with a blower at one point his to get disconnect switch or power burner or navy coal Stoker or all the above at one point or another as I said 30 amp disconnect switch 30 amp cartridge fuses about what you find for the window unit connected to arrange disconnect pull the house is wired originally of black pipe like what's looks similar to gas pipe except this is the rigid conduit the size boxes that do not fit modern covers I think this should help update you on the date of building and one thing of note that disconnect switch for the furnace in the Asian wiring more about that disconnected moment I do believe that possibly the original service funeral who would very well have been wait for it fused neutral panel it don't worry it's every 110-volt circuit and that's why I'm may have had to fuse one in line what Dallas black heart the AR is what now will be white neutral very very very dangerous I've run across to the few tulips usually podcast or I was able to bring some sort of bypass temporarily or swap out the neutral fuses for 30s SM plug fuses usually although I have seen we're not this is not your afraid thing but here Fairwater fuse links one of these was installed in Joyce hey hey hey an attic full of insulation just we start a fire and above that the old first entry systems had to say systems as in fire grenades that most themselves or potion themselves and I think it generates maybe wrong I think it was carbon tet carbon tetrachloride he knows things we want to come across a used it's ever went off the occupants could be dead I'm not talkin smoke inhalation or fire I'm talking about the products of the earth system trying to put out said fire poisoning them if you're interested Google Fire Grenade or Wikipedia or even here on KZfaq where fact there's a few of these or somewhere search where talks about these things around the Border a few good examples here on KZfaq they were disinterested on Fire Equipment source of book I have one that's not hermit at but it's an earlier one than that it's a little salt water and it's confirmed that salt water because that the markings it's a bracket that's their brass in my parents I'm sure the bedroom where I stay when I'm with them same one that has the odor not sewer they said that it's very possible the gurgling toilet maybe due to a septic that needs to be pumped because I remember it happened to my grandmother sometimes when I was younger that's the first thing she am I then living grandfather would notice it later it back up into the bathtub was it worse yuck but then you'd have to dig up the lid now they have a pump out connection that they just hook up a hose quick coupler for pump out. Oh by the way how often should a septic tank be checked roughly on average for two people living at the house and go dishwasher and Wanda washing machine one shower 1 sink double occupancy roughly and as I said before it's datrek issues so looks I will look to the right channel to the first place go figure thanks peace out and keep up the by the way the one about the one that starts with the propane I was in that same restaurant as working on this computer system ones and this is just helping someone and weather Refrigeration use fire like I don't think that was strictly logical I said to them I think there's a flammable gas fire refrigerator and gas heating unit know it's Refrigeration what was that would had to be one that runs on propane right and he says yes it's charged for propane or was he said not anymore I looked at it I said yep there's a nice big hole with that compressor where that compressor Terminal ship and that was no more and I speak skidmark in the paint on the unit actually that was some sort of tag or schematic the blower that was clearly chard good proper looking forward to new videos also could you please talk about some of the old I'd say almost antique units that use refrigerants now that can never legally be recharged because the dangers involved mainly because of Hazards of the refrigerants you don't like ones that would gas you if you ever broke it and also I have witnessed an old refrigerator be move with the coils on top I think it was at a campus at when we were cleaning out the old junk yard for scrap impossible resale of anything that could be a value mainly as a antiques such as the old sharpening stone with a treadle that was a museum-quality piece. back to that refrigerator I think it may have been ammonia based on what has happened and how they react to the as it was like when it went you could see a cloud of white not like your refrigerant spray from the damaged line like at seeing some videos Note. that refrigerator did have a compressor this is not one that used ammonia absorption hydrogen water in the boiler and gas flame or electric heater or a caarosenelamp with a mettle chimney instead of glass. Sort of like a modifide magic lantern chimney for erley projection. of course we called the EMTs and they said is a possibility but they could not rule out out or deny or confirm does ammonia because there's no documentation on the unit we searched everywhere on it oh by the way to compressor the connections should have compressor from valves lines or flanges with a fairly decent size screw on your side look more like a hydraulic flange then a refrigeration or are coupler almost like what you might find on some small engine Muffler connections and gaskets in cylinder heads by the way it look more like an icebox Style or made from parts for an ice box is then converted to refrigerate box for one thing the car scheme was off for the coils or of a different type of paint although almost insane car but not quite but slightly different finish like the refrigeration was an afterthought the only other place I've seen where these is a museum One more clue SCH I just remembered actually to the cord was not well you might think 2 wire cloth covered or possibly silk although it was white if I can remember well maybe another color and the plug end of it not what you think. Pins or prongs but medium Edison screw shell AKA Vue or standard size 40 or so watt 200 some-odd watt light bulb base AKA Well. before we would normally use the two prong socket most places where you would use a convenient light socket to plug in an electrical Appliance more corectley scrue in it oh by the way in that place also someone else to date probably a lot of stuff was there probably before even that time possibly What was then the Art Shop is what used to be a laundry facility which was interesting for thing 30s that log sink is trough sink there's also similar one on the bathhouse where I used to go to camp As well as in that laundry for soy has now the orange shop there was what store made of an old line shaft system and the boiler was still in the O building one time I ask for permission to pull some boards out and check it out I did get photos and also I salvageable gauges in your gauge siphons Since I'm interested in steam power and boilers and such

On those direct drives do they not have a module to adjust speeds? Or the ability to add on? I absolutely love these videos because this addresses such a huge issue in restaurants. Less and less you see restaurants with dedicated make up, all want to use ac economizer and transfer air from dining to kitchen. I'm always interested how everyone goes about getting the balance correct after repairs to the ac or exhaust systems. Thanks again for all your effort you put into these videos 👊

I have a question with you putting economisers on 100% will the kitchen in the summer time be cooler or no?

A problem that some people overlook.

5:00 Um that's not kinda dirty, that's FUBAR lol! Bet the amp draw is pretty low too!

Good job, on balance. I think with amount of exhaust hoods/make up air is needed. Just my opinion.

Are those real green trees in the background? Are you sure you haven't moved to Tennessee?

Where do you go to learn more about this kind of problem calls. My boss asked me the other day if I knew how to work on them. I thought about you when he asked.

0.02" perfect

What about opening the sheaves on the exhausts (while measuring amp draws on the motor) then close sheaves a bit on rtu's while testing static pressure.

Oh wow no make up air. How is that possible. Those 4 exhaust fan may pulling out so many thousand cfm. They gonna have cooling or heating problem while using economizer sucking those outside air in.

How do those Allen-Bradly VFD's break? What were the error codes? They are serious industrial equipment, it doesn't just break in a kitchen. Don't you think it might be the control box?

Nice video is it still possible to put a makeup air in

Do the exhaust fan motors have internal overloads?

How many trips have had there, in what amount of time?

👍👍👍

If you have sewage smells (methane or H2S)due to negative pressure inside building that could mean one or more waste pipe P traps or gas traps in the waste lines are not fitted on all waste pipes or some have no water in them. Should never happen that sewage smells come back from waste pipes except for above mentioned issues. Hygiene hazard in an eating establishment.

@ 6:58 exactly ;)

Altering factory installations voids all ul ratings and leaves your company suseptable to a huge lawsuit. Believe me, telling the judge the client didn't want to won't get you off the hook. In the trades we have to do what's right regardless of what client wants

With all the outside air units open, won’t their efficiency go down the drain? You’re pulling in hot and cold air with the different seasons

Couldn't toilet smell be coming from bathrooms where exhaust fan isn't working?

Wonder who did the PM last..:)

Where did you hook up your manometer at?

You could reduce pulley sizes to lower exhaust fan speed

Sounds like the cost of the extra energy consumed and modifying in repairing all the other fixes to overcome the broken VFD’s will far exceed the cost of repairing the VFD’s. What if the customer is one of those you got an A in economics or business management on a piece of paper but doesn’t know how to apply it, lol. If the VFD‘s were from ABB or Dan Foss with the reactors and filter the high-end models they would not have broken down in the first place if properly wired they would get 8 to 10 years out of them probably still be working and just have to send them in for servicing in their normal 10 year cycle for maintenance.

Health code VIOLATIONS. Has to be 10ft away from oa damper. If it is high humidity outside its going to make all kinds of moisture problems.

That kitchen unit looks like it has a power exhaust on the side, shouldn’t it come on when the fresh air / economizer reaches 100% Would probably make the negative pressure worse.

Wouldn't it be cheaper in the long run to to just repair it the right way ?

They’re not gonna pay for economizers if they won’t pay to fix the exhaust system lol. Fixing the exhaust is the only solution and the money they’d save with the vfd’s in play

Dang, could not kill one of the exhaust fans?

Nevermind the last question

frankly id rather have them run full tilt 24/7. Some brain box controlling the hood system seems like a bad idea to me

how on earth can you know the tension by just boncing your thinger like that? twist the dam belt that will get you a good reading

I have this same issue at a restaurant I work on. No makeup air. The two rooftop units have Jade economizers so we opened them up 20 percent to “solve” the issue. They had no interest in adding a makeup air.

Oh my goodness I'm watching the continuation of the video what you're recommending the customer not only isn't it cost more in the long run make your company look like s*** to them because at the end of the day you're still going to have to fix the vfd controllers and if all your concern is is cheekness on a vfd controller did you can pick up a $200 one night you don't made by Siemens or you know another and just manually set it so when it starts it only goes to 50 hertz or whatever the low speed would have been or set it with a simple sensor so it can work properly but what you're doing no because the customer we don't Jerry rig crap this is why I hate normal HVAC text well anyone that's supposed to know what they're doing once you start Jerry rigging it's over

I really have to wonder, why you would buy a "smart" system and then not spend the money keep it running?

Its the same everywhere, restaurant owners are cheapos, when you remove air, you have to ad air. Simple as that, yet every f#*#$%*n time i get confronted with this same crappy situ. 😧😧😠😠

No video just audio

Oh my God after watching it to the end are you that bad go online simple search for vfd controller and you can program an overpriced so-called OEM part and you could probably find that exact controller online don't go through the manufacturer it's a simple man a vfd controller is basically also in your electric car your RC toys your Tesla your new HVAC systems oh my God I don't want you touching any new HVAC systems oh yeah we'll just run a hundred percent OMG

Okay so you're the reason for their negative pressure problem because you didn't realize that when you power all the vfg drives which let's be clear they're not vfd drives their three phase AC motors that were running off vfd drive modules variable frequency drive controller that is what 5 $700 part depending on how high end they are which I assume aren't you need to go back to the customer and tell them they need to replace the vfd controllers and if not you will not provide service again technically right now if I was at business owner I'd be on the phone with my lawyer and I'd be seeing okay this guy allowed our business to suffer by making a mistake allowing our place to basically smell like s*** and we've lost money because of it I think that business actually has a legal case against you cuz in this video you just admitted that you did the work and yes ignorance unfortunately is not an excuse I'd also be taking a look at that walk-in cooler refrigeration system looks kind of janky old but yeah a very solid letter that says this is what you have to do and if you don't do this we won't do any more work because you're just creating more liabilities for yourself another thing is now one I would not be altering those control boards while the system is running even though you can yeah not a good idea they're going to have a higher energy bill because it's going to be heating that place exchanging the air more fix the hoods the right way and tell the customer they have to do it that way there's no essence but about it