Hello from Greece!I watch your videos long time ago and I find them very helpful for my every day work. Because here we are Europe we have a completely different equipment in refrigeration and a/c systems but the basics it's the same. Keep on the good work my friend. Ilias Mpellos hvac/r technician.
Great video Chris. I worked on a Hoshizaki cuber with a remote condenser, the coil was literally 2 feet away from the kitchen exhaust hood, and this place specialized in French fries... I wish architects & kitchen designers would consult the trades more often to supplement their knowledge, things would go better for these restaurants if they did.
Like always thank you for your your teaching and sharing your knowledge and information, you are good person taking your time to teaching , God bless you and your family.
It is the evaporator coil plugged with grease and debris that sticks to it. The TXV is locking down due to poor heat absorption and poor airflow thru it.
I love watching your service call videos. I have learned so much. I enjoy diagnostics as a technician and I enjoy refrigeration. I service almost everything and your videos have expanded my knowledge into refrigeration. Keep it up. Thanks!
I will be going live on UA-cam this evening 8/19/19 @5:pm (pacific time) to discuss my most recent uploads and answer questions from UA-cam comments, the chat, and emails. Come check it out if you can ua-cam.com/video/cFVJGl-KVEc/v-deo.html
I have worked commercial install and can tell you for a fact if they screw up the bid the duct work is the first thing that gets cut back; thinner metal or smaller pipe. Another thought would be insulation that has come loose and blocking airflow. Worst bet grab the ole balometer hood and start taking readings, no just kidding save that for the Balancing crew. I have a few ABM 200’s and can get a basic check of airflow with those. The best part of our job is how much knowledge we gain and the worst is how many tools we have to carry.
I did the same and now I'm a few months in the field and the best advice my teacher told me was to take the textbook and go into the attic and study. Thats what the job is like.
I just find your channel, and like it very much, I watch several videos and compared it with my job, and can always help me to improve my work and may get a shortcut, very appreciate. To deal with the situation in this video, I may jump out of the airflow issue, and focus on the evaporator coil pressure and the condenser coil pressure more, and if the air supply can be acceptable, the DELTA T, the condenser split (20 -30) and the compressor RATIO ( 2 - 3) should be taken care more.
I'm continuing to catch up with your videos. Each one is fascinating the way you go through things plus you've put up a lot of stuff I didn't know or thought of. You might get a few more comments from me as I explore your history of video's, don't stop they are both entertaining and educational and not only in your field. (having a couple problems my backspace key's broken so forgive the odd spelling problem,,, I'll take a leaf out of your book and find a work around) keep doing what you do. Thank you. For some strange reason some don't know what thank you means, it's a simple response to appreciate a person's time, ability or service and should be used a lot more, it cost's you nothing but appreciation for what the person or person's do. I am suprized that more open air jobs aren't being run after all if your by yourself who are you going to infect and even then wouldn't need to much distance. Keep safe look after your self and family and I'll join you in a wish for a better future. Thank you.
Hey Chris, Not an AC tech, I am a Security Tech but have an interest in AC and BMS. I think that all the UA-cam creators are great for sharing their knowledge but most fail on one point, the main point you excel at, you admit you do not know everything That is a massive statement to own in this day, where customers expect you to be a rocket surgeon in your field ;) As I used to tell the Pre Apprentices "There is only one stupid question in the world, do you know what it is ?" After they have a few stabs I used to reply " The only stupid question in the world is the one you do not ask !"
I'm guessing clogged evap, slightly low suction, high delta, valve slightly closing due to colder suction and possible overcharged to overcome the underlying issue leading to high sub and head pressure.
At an old spaghetti factory I found two dampers that were installed in the return for some reason. I removed them and the unit worked with out Icing up. It’s tough depends on the install. Most duct in commercial has to be hard piped if they ran flex a duct could be collapsed in the drop ceiling
Whenever you get a high pressure cutout you have to check as much as you can with a compressor. Had the same issue on a RTU (voyager, imagine that) and a transformer kept tripping whenever the 2nd stage tried to kick in. I ended up replacing a crankcase heater for starters. Next I went through resistance, and then amps, compressor checked out good. Went to start the unit up, same problem. Had to reset Tracer and tug on some wires connected to a HP cutout. Unit started up no more issues. If you're convinced airflow is the issue adjust what you can dude, don't beat yourself up about it. I've found installs not even complete: one business owner had a 4 ton system (thought was 5 ton), with open 4" supply branch in air handler space just hanging (didn't even see what it was supposed to connect to..), which was direct return... I blanked it off and told him he had a major ductwork issue, for free! I was just curious as to why his restaurant was 91 degrees with cool air dumping. If the install is that messed up then overhaul is the only option.
@@redangrybird7564 I would say you get what you pay for but, that doesn't seem to be the case. I believe it's a major issue of installation not being taught but learned on the field. It's just criminal what you find out there, and there needs to be inspections done for every install.
Lol "Bubble party from Vegas" sad how some people get away with doing subpar work..it gives all of us honest Technicians a bad name. Keep up the good videos Chris-
First thing I would check is the motor amp draw at 60 Hz to make sure it's close to max with the door off. If it's low, then you aren't moving enough air. Check the blower pulley setting, belt, tension, and if the wheel is dirty. EDIT: I can see the VFD display says 7.2A, unit spec is 10.6A (upper left of display) so you're only running at about 68% of max airflow. Maybe need to adjust pulley for more airflow, I'd adjust it until I got 10.0A on the VFD with the door off.
Also, you probably know this, but hunting TXV superheat like you saw there is very indicative of low evaporator heat load because the TXV is being forced to operate in the very lower limits of capacity where the response isn't very linear. A lot of guys see hunting superheat and automatically assume the TXV is bad, but you really have to check both the charge and the evaporator heat load (not just airflow) to make sure you are in range. Sometimes in low latent conditions (like what you have there) you really have to ramp up the airflow (500+ CFM/ton sometimes) to make the evaporator heat load target (∆ Enthalpy in mQ) so the TXV can be in a capacity range with good hysteresis characteristics. You can get better efficiency doing this as well. I guess what I'm getting at is don't be afraid to tweak the airflow with a pulley or blower control adjustment if you see a hunting TXV and low airflow, just watch your static limits. For this 15 ton unit you probably want to see 7000 CFM or more of airflow. Interesting that measureQuick is also showing your airflow at about 2/3 of desired which matches the low amp draw amount, good program!
Agree, much more info needed though.. I was also thinking if that unit had humidity control or not, ductwork/blower dirty, actual air balance between exhaust/makeup, etc...Like chris said in video gotta figure out airflow first. AIR Conditioning
Assuming that this is a constant velocity unit, you should focus first on IFM amps. Has a proper start-up ever been done on this unit? You may be at full speed with VFD, but are the IFM motor sheeve and fan pulley the right size for proper airflow? IFM amps are key. .9 “ WC is not overly bad on a CV unit, 1” is generally ok. Check delta T. Manually open economizer and see if static pressure increases indicating undersized return or clogged air filters or dirty evap coil. Tripping on high discharge pressure? Check condenser fan motors for shaft play and check amp draw. Motors may be cycling on overload after run time, or after ambient temp increase, due to worn bearings. Adjust refrigerant charge for proper SC and check superheat, adjust SH as necessary. Recheck SC. Make sure all supply grills are open. With that kitchen exhaust fan location, unit will always be a problem.
Wow cool! Look at all those bubbles. I love watching your videos I even tried to play them on the family TV, the family were not as interested as me in HVACR videos 😀👍
EF issue: Install a 4' piece of glav. 18"? 20"? spiral with a companion flange mate to the fan so you can take it off each time to service. and/or install 2 or more large access doors in the spiral so you don't have to remove each time. Bonus, install a slightly larger piece of spiral, slightly below the lip of the fan to allow an airgap, which will bring fresh air to mix with exhaust air before it leaves the top of the spiral.. Edit: Thanks for uploading!
That micro channel can really make some high head issues..especially with the grease...even if cleaned that grease coats the creases and really prevents the heat from being released from the coil. I have 2 r404 freezer units on the ground with alot of debris within the vicinity and it plays hell sometimes. If they dont care enough to fix...they will care enough to pay to keep you coming back Chris...JOB SECURITY BOSS MAN..👍😁💰
Definitely as per another comment check the VFD actual frequency generation is what the requested frequency generation is - and don’t assume that 60Hz is the *upper* limit - the whole point of VFDs is that they are capable of generating motor frequency inputs *in excess* of line frequency (although that may not be the the case for this RTU’s fans...) Another issue with the airflow is negative building pressurisation - too much air is being sucked out through over enthusiastic exhaust / extract systems (hoods, building pressure control). This may be a transient feature if different exhaust fans are sometimes running, sometimes not (restrooms, the kitchen, makeup air systems....) - but when the building is having too much air removed, this will lower static pressure in that RTU’s SA duct run, but when the too-great exhaust air system cuts out, you’ll be back in a higher static pressure situation. Really needs a duct designer / architect / airflow and pressure expert to investigate the building’s operation *as a system* - you’ve got insufficient data and measurement ability from your humble (!) position as the HVAC service tech (although you, of course, have to deal with the issue at the point where it is manifesting itself :-) ) Thanks so much for another great video.
90Hz is the highest I have seen on a VFD output for a fan mtr. The motors are supposed to be special made to support the extra drive Hz. VFDs eat bearings, and I have seen a 2,500hp MTR that someone forgot to install the anti-EDM rings, I have seen motors where the rings were blinded with grease, I have seen pump bearings that were ate up by edm because they used a metal coupling and the path to ground was easier through the pump bearings, VFDs keep me employed. Also there is no feedback loop to the VFD, just because it says it is sending 60Hz doesn't mean the mtr is running at that, I mean well more than slip, if you suspect something it would be wise to check the RPM to confirm that the mtr is running as it should.
with that close proximity, i'd feel inclined to put a filter medium behind the hail guard. or plan-B, reverse the direction of the cooling fans to draw less greasy air from above and blow it towards the extraction fan (?)
Just an idea, but maybe take isolated static pressure measurements to see how the separate units interact/overlap & perhaps where that supply drop occurs? 1. RTU only 2. RTU + MUA 3. RTU + MUA + EXHAUST
I swore off of the self foaming cleaners a while ago. Now I just use the Evap Pow'r-C and more time when I am doing the checkup/maintenance on the family and friends condensers.
chris hilton wow. We have the opposite problem here in my little part of Florida. All MUA seems to be 25% low in kitchen as the big hood contractor always assumes the business is putting in conditioned MUA off the ACs.
Just a thought , for the grease issue / Try putting a screen between the them ( like a windscreen on a sliding door ) it would catch the grease and allow fair amount of air before becoming to coated / and just switching out the screen when coated and soaking it clean while another is in place. Just a couple of metal poles and screen ( or maybe a small chain link type ). As for the airflow. I agree with Chris that if fresh air unit is over powering the kitchen it maybe the humidity giving odd airflow reading (as it is thinning out air in cooling and leaving enough to balance the readings. Just a odd thought. ) Love your video, your vids have help me out a ton...i know bad joke. Keep up the awesome work.
At least they had the good sense to put hail guards on them. Go out to a site and the entire roof is covered with golf ball RTUs. Don't work worth a damn, but they sure are aerodynamic.
You really need a hot water pressure washer with a 1000 psi max operating pressure and a flow of 2 gal per minute. This combo would not hurt anything fin wise and flow enough volume to maintain enough heat to effectively remove the grease. Those condensers will wick away the heat really quickly if your GPM isn't high enough. You can also introduce your favorite cleaner into the system if you deem it necessary.
put a new outdor unit and A coil in a older existing duct system.started unit,found the problem with old unit.,no supply air or very little. check blower wheel.coated in grease and dust.no incline on blades.cleaned fan,what a difference.like night and day!
Sounds like a airflow restriction before the evap coil, either a dirty coil or filters. Could even be inline return grill filters on the registers or a dirty fan barrel.
Before seeing what you did as a solution for the kitchen exhaust fan/grease problem, I think I would do a wind screen type shield for that side of the micro channels,
wonder if supply blower motor, if belt drive, is fully loaded? Maybe bigger drive pulley to increase blower RPM to full motor load, increasing static into main supply duct.
Most excellent thought and Suggestion.I so know Dawn dish soap has a really great surfactant for Removing the greasy surface tension .But it also bubbles Alot! dishwasher detergent should be better ,i agree!
I gather you explained the clogging caused by being badly positioned next to the vent and the impact on the units performance and the need for a solution but I didn't catch if they wanted a solution.
I once experienced a greased air exhaust blowing onto the condenser coil... It was a job removing the grease,,, Eventually the customer directed the exhaust air the other way...
static pressures fairly low and cold supply, maybe the blower isn't on highest speed tap, worn belt slipping or getting slow from weak capacitor. same for condenser fans unless it's all 3 phase or vfd. looks like one of them head scratching things and it sucking hot exhaust hood air sure isn't helping. after the other post I heard you mention servicing with an extension being a pain, there should be quick release ones that just latch on and off easily, it wouldn't take but a minute more to service
Was the belt on the blower loose at all? I was also thinking for the exhaust fan that maybe you could have a custom elbow made and have it throw the exhaust out on the opposite side, just a thought..
Wonder if the motor sheave was adjusted to a lower airflow, therefore not causing high static. Not sure why that would be done other than duct issues. If someone did that, they weren't thinking about suction temps
Don't know if u have seen it, but I've noticed that the 400 series refrigerant had drier issues. My theory is the poe starts to wax or the varnish starts coming off of the compressor windings. I think it has to do with high pressure and the poe
I do mainly residential but I've hit commercial here and there the last 11 years of doing this. I've wondered about the tricks of getting that water out of the micro channels I've used nitro when it's on the ground or just take a lunch and let it sit with the cfms running. You in socal? Scenery looks familiar in some videos.
Microchannel condensers look weird on the video, probably because of the small hole pattern being really funky with the camera resolution. Always get some funky Moire patterns on the screen.
Good work, Did you check the blower wheel to see if it is full of grease, and also check fire dampers? I have had both issues in the past with both restaurants and hospitals. Thanks for the excellent video[s.
Can you see the hz frequency feed back ? Sometime even if drive say 60 they aren’t running at that. It could be what the unit asking forThere are typically two things on drives you actually have your analog input what you’re asking to drive to run it and then you could have a Feedback telling you what it’s actually doing and that 60 Hz could just be what the units being asked to run at
4:45 mark. I think you mean low head pressure. You're never going to trip a unit on high head with the condensing coil saturated with water. Also at that same mark, it appears as though you need the rinse the detergent out of the coil and the unit. No way would I have left the all of the foam in the coil or unit.
I think the only real solution is a hood extension but its gonna suck when servicing the fan! They get high winds here so it has to be anchored down and able to handle 30-40 mph gusts....
@@HVACRVIDEOS Captive aire makes nice removable windband extensions that will clamp to the existing flat flange on their fans. If you make one yourself, avoid galvanized, it is difficult to clean.
New to the channel, nice vids! What do you use to shoot your video? I do a lot of field work with industrial equipment and the post install videos are priceless, but the quality of my phone is only so so.
I’m having trouble understanding how you could have a high-temperature split with low static pressure. Low static pressure typically indicates good airflow, so it seems contradictory. I suspect the placement of your temperature probes might be causing the high-temperature split. Additionally, a high-temperature split should affect pressure on both sides of the unit, meaning pressure would be low throughout even if the unit is close to the exhaust fan. I’m puzzled by this discrepancy.
Hey Chris, I'm probably talking rubbish , but would it be possible that the exhaust being so close would take out a lot of the flow , so that there's not enough air flow left to be taken by the package unit return air so to speak , if that makes any sense ?
If it wasnt for fly by night installers and Chinese and Mexican made parts our job demand would decrease about 50%. You burped that condenser like a proud dad. Funny stuff.
Hey Chris, Thank you for posting great work.
Thanks for watching!
“Like a damn night club in Vegas” that part had me dead 😂
SAME!
Same bro hahahaha
Hello from Greece!I watch your videos long time ago and I find them very helpful for my every day work. Because here we are Europe we have a completely different equipment in refrigeration and a/c systems but the basics it's the same. Keep on the good work my friend. Ilias Mpellos hvac/r technician.
Great video Chris. I worked on a Hoshizaki cuber with a remote condenser, the coil was literally 2 feet away from the kitchen exhaust hood, and this place specialized in French fries... I wish architects & kitchen designers would consult the trades more often to supplement their knowledge, things would go better for these restaurants if they did.
Oh my god that beginning had me dying, i needed that after the night i had. As an ammature HVACR tech, i love these videos and learn so damn much.
Like always thank you for your your teaching and sharing your knowledge and information, you are good person taking your time to teaching , God bless you and your family.
It is the evaporator coil plugged with grease and debris that sticks to it. The TXV is locking down due to poor heat absorption and poor airflow thru it.
Thanks for all you do ...for always going above and beyond
I love watching your service call videos. I have learned so much. I enjoy diagnostics as a technician and I enjoy refrigeration. I service almost everything and your videos have expanded my knowledge into refrigeration. Keep it up. Thanks!
I'm trying to learn the HVAC field. Your videos are appreciated keep them coming. God bless
Can confirm, definitely like a Vegas Night Club.
Great video, I have increased my understanding of troubleshooting just from your videos. Night club in Vegas classic!!!!!
Hey man, just wanna thank you very much for these videos. I’m from Seattle and learn from your videos all the time.
I will be going live on UA-cam this evening 8/19/19 @5:pm
(pacific time) to discuss my most recent uploads and answer questions from
UA-cam comments, the chat, and emails. Come check it out if you can ua-cam.com/video/cFVJGl-KVEc/v-deo.html
Summary: Unit has a high cholesterol diet, clogged arteries and poor circulation, recommends diet change and let some gas out, lol.
signed,
Dr HVACR
I have worked commercial install and can tell you for a fact if they screw up the bid the duct work is the first thing that gets cut back; thinner metal or smaller pipe. Another thought would be insulation that has come loose and blocking airflow. Worst bet grab the ole balometer hood and start taking readings, no just kidding save that for the Balancing crew. I have a few ABM 200’s and can get a basic check of airflow with those. The best part of our job is how much knowledge we gain and the worst is how many tools we have to carry.
Always love watching your content starting trade school soon for hvac but I’m watching you and already learning a ton of information
I did the same and now I'm a few months in the field and the best advice my teacher told me was to take the textbook and go into the attic and study. Thats what the job is like.
Eel Feel learn how to use your multimeter good and reading schematics.
Good work have found many curb adaptors not sealed properly causing supply to recuculate into return
I just find your channel, and like it very much, I watch several videos and compared it with my job, and can always help me to improve my work and may get a shortcut, very appreciate. To deal with the situation in this video, I may jump out of the airflow issue, and focus on the evaporator coil pressure and the condenser coil pressure more, and if the air supply can be acceptable, the DELTA T, the condenser split (20 -30) and the compressor RATIO ( 2 - 3) should be taken care more.
Thanks Chris, you certainly know much more about AC units than me. Cheers, take care.
😁👍
Great videos, thank you sir. I learn a ton of info from you. I also appreciate your showing us how to do it right. Thank you!
I'm continuing to catch up with your videos. Each one is fascinating the way you go through things plus you've put up a lot of stuff I didn't know or thought of. You might get a few more comments from me as I explore your history of video's, don't stop they are both entertaining and educational and not only in your field. (having a couple problems my backspace key's broken so forgive the odd spelling problem,,, I'll take a leaf out of your book and find a work around) keep doing what you do. Thank you. For some strange reason some don't know what thank you means, it's a simple response to appreciate a person's time, ability or service and should be used a lot more, it cost's you nothing but appreciation for what the person or person's do. I am suprized that more open air jobs aren't being run after all if your by yourself who are you going to infect and even then wouldn't need to much distance. Keep safe look after your self and family and I'll join you in a wish for a better future. Thank you.
Hey Chris, Not an AC tech, I am a Security Tech but have an interest in AC and BMS. I think that all the UA-cam creators are great for sharing their knowledge but most fail on one point, the main point you excel at, you admit you do not know everything That is a massive statement to own in this day, where customers expect you to be a rocket surgeon in your field ;) As I used to tell the Pre Apprentices "There is only one stupid question in the world, do you know what it is ?" After they have a few stabs I used to reply " The only stupid question in the world is the one you do not ask !"
I'm guessing clogged evap, slightly low suction, high delta, valve slightly closing due to colder suction and possible overcharged to overcome the underlying issue leading to high sub and head pressure.
yes, i would have took a pressure measurement across evap and consult manufacturer specs on what it should be
At an old spaghetti factory I found two dampers that were installed in the return for some reason. I removed them and the unit worked with out Icing up. It’s tough depends on the install. Most duct in commercial has to be hard piped if they ran flex a duct could be collapsed in the drop ceiling
Whenever you get a high pressure cutout you have to check as much as you can with a compressor. Had the same issue on a RTU (voyager, imagine that) and a transformer kept tripping whenever the 2nd stage tried to kick in. I ended up replacing a crankcase heater for starters. Next I went through resistance, and then amps, compressor checked out good. Went to start the unit up, same problem. Had to reset Tracer and tug on some wires connected to a HP cutout. Unit started up no more issues.
If you're convinced airflow is the issue adjust what you can dude, don't beat yourself up about it. I've found installs not even complete: one business owner had a 4 ton system (thought was 5 ton), with open 4" supply branch in air handler space just hanging (didn't even see what it was supposed to connect to..), which was direct return... I blanked it off and told him he had a major ductwork issue, for free! I was just curious as to why his restaurant was 91 degrees with cool air dumping. If the install is that messed up then overhaul is the only option.
It seems that there is a whole bunch of cowboys doing some bad installations and giving the good tradesmen headaches.
@@redangrybird7564 I would say you get what you pay for but, that doesn't seem to be the case. I believe it's a major issue of installation not being taught but learned on the field. It's just criminal what you find out there, and there needs to be inspections done for every install.
Get the disco ball out it’s time to party, Great video Chris, Your channel ROCKS !!!!
Lol "Bubble party from Vegas" sad how some people get away with doing subpar work..it gives all of us honest Technicians a bad name. Keep up the good videos Chris-
First thing I would check is the motor amp draw at 60 Hz to make sure it's close to max with the door off. If it's low, then you aren't moving enough air. Check the blower pulley setting, belt, tension, and if the wheel is dirty. EDIT: I can see the VFD display says 7.2A, unit spec is 10.6A (upper left of display) so you're only running at about 68% of max airflow. Maybe need to adjust pulley for more airflow, I'd adjust it until I got 10.0A on the VFD with the door off.
Also, you probably know this, but hunting TXV superheat like you saw there is very indicative of low evaporator heat load because the TXV is being forced to operate in the very lower limits of capacity where the response isn't very linear. A lot of guys see hunting superheat and automatically assume the TXV is bad, but you really have to check both the charge and the evaporator heat load (not just airflow) to make sure you are in range. Sometimes in low latent conditions (like what you have there) you really have to ramp up the airflow (500+ CFM/ton sometimes) to make the evaporator heat load target (∆ Enthalpy in mQ) so the TXV can be in a capacity range with good hysteresis characteristics. You can get better efficiency doing this as well. I guess what I'm getting at is don't be afraid to tweak the airflow with a pulley or blower control adjustment if you see a hunting TXV and low airflow, just watch your static limits. For this 15 ton unit you probably want to see 7000 CFM or more of airflow. Interesting that measureQuick is also showing your airflow at about 2/3 of desired which matches the low amp draw amount, good program!
Agree, much more info needed though.. I was also thinking if that unit had humidity control or not, ductwork/blower dirty, actual air balance between exhaust/makeup, etc...Like chris said in video gotta figure out airflow first. AIR Conditioning
Great video !, one of the best Hvac-R content on UA-cam or anywhere really!
Assuming that this is a constant velocity unit, you should focus first on IFM amps. Has a proper start-up ever been done on this unit? You may be at full speed with VFD, but are the IFM motor sheeve and fan pulley the right size for proper airflow? IFM amps are key. .9 “ WC is not overly bad on a CV unit, 1” is generally ok. Check delta T. Manually open economizer and see if static pressure increases indicating undersized return or clogged air filters or dirty evap coil. Tripping on high discharge pressure? Check condenser fan motors for shaft play and check amp draw. Motors may be cycling on overload after run time, or after ambient temp increase, due to worn bearings. Adjust refrigerant charge for proper SC and check superheat, adjust SH as necessary. Recheck SC. Make sure all supply grills are open. With that kitchen exhaust fan location, unit will always be a problem.
Wow cool! Look at all those bubbles. I love watching your videos I even tried to play them on the family TV, the family were not as interested as me in HVACR videos 😀👍
If temp split is that much with low static personally would check. Blower motor maxed out on amps? Dirty blower wheel? Wrong pulleys?
EF issue: Install a 4' piece of glav. 18"? 20"? spiral with a companion flange mate to the fan so you can take it off each time to service. and/or install 2 or more large access doors in the spiral so you don't have to remove each time. Bonus, install a slightly larger piece of spiral, slightly below the lip of the fan to allow an airgap, which will bring fresh air to mix with exhaust air before it leaves the top of the spiral..
Edit: Thanks for uploading!
Love your videos...
like you say ....every day is a new day ...👍👍👍
That micro channel can really make some high head issues..especially with the grease...even if cleaned that grease coats the creases and really prevents the heat from being released from the coil. I have 2 r404 freezer units on the ground with alot of debris within the vicinity and it plays hell sometimes. If they dont care enough to fix...they will care enough to pay to keep you coming back Chris...JOB SECURITY BOSS MAN..👍😁💰
Totally Agree on this point!
Haha 🤣 it’s like a foam party that happens in one club in my town and we all know how foam party’s go
Definitely as per another comment check the VFD actual frequency generation is what the requested frequency generation is - and don’t assume that 60Hz is the *upper* limit - the whole point of VFDs is that they are capable of generating motor frequency inputs *in excess* of line frequency (although that may not be the the case for this RTU’s fans...)
Another issue with the airflow is negative building pressurisation - too much air is being sucked out through over enthusiastic exhaust / extract systems (hoods, building pressure control). This may be a transient feature if different exhaust fans are sometimes running, sometimes not (restrooms, the kitchen, makeup air systems....) - but when the building is having too much air removed, this will lower static pressure in that RTU’s SA duct run, but when the too-great exhaust air system cuts out, you’ll be back in a higher static pressure situation.
Really needs a duct designer / architect / airflow and pressure expert to investigate the building’s operation *as a system* - you’ve got insufficient data and measurement ability from your humble (!) position as the HVAC service tech (although you, of course, have to deal with the issue at the point where it is manifesting itself :-) )
Thanks so much for another great video.
90Hz is the highest I have seen on a VFD output for a fan mtr. The motors are supposed to be special made to support the extra drive Hz. VFDs eat bearings, and I have seen a 2,500hp MTR that someone forgot to install the anti-EDM rings, I have seen motors where the rings were blinded with grease, I have seen pump bearings that were ate up by edm because they used a metal coupling and the path to ground was easier through the pump bearings, VFDs keep me employed. Also there is no feedback loop to the VFD, just because it says it is sending 60Hz doesn't mean the mtr is running at that, I mean well more than slip, if you suspect something it would be wise to check the RPM to confirm that the mtr is running as it should.
simplest solution is likely adding a "stack" on top or raising the whole thing up on round duct so it's over top the unit.
with that close proximity, i'd feel inclined to put a filter medium behind the hail guard.
or plan-B, reverse the direction of the cooling fans to draw less greasy air from above and blow it towards the extraction fan (?)
Add peeps recommend Triple D coil cleaner on micros. But viper makes some good stuff. Good vid. Keep it up. Nice work. Love the vids.
And probably agree. Undersized duck. So common. On service old buildings
Just an idea, but maybe take isolated static pressure measurements to see how the separate units interact/overlap & perhaps where that supply drop occurs?
1. RTU only
2. RTU + MUA
3. RTU + MUA + EXHAUST
I swore off of the self foaming cleaners a while ago. Now I just use the Evap Pow'r-C and more time when I am doing the checkup/maintenance on the family and friends condensers.
Awesome videos and hey by coincidence I happened to do some fiddling on Google Earth and found the place where you were working at. Lol
try checking for higher than normal internal pressure In the kitchen, you may have the make up air bringing in way to much and over pressurising
Also a consideration worth checking out!!Good suggestion.
chris hilton wow. We have the opposite problem here in my little part of Florida. All MUA seems to be 25% low in kitchen as the big hood contractor always assumes the business is putting in conditioned MUA off the ACs.
Just a thought , for the grease issue / Try putting a screen between the them ( like a windscreen on a sliding door ) it would catch the grease and allow fair amount of air before becoming to coated / and just switching out the screen when coated and soaking it clean while another is in place. Just a couple of metal poles and screen ( or maybe a small chain link type ). As for the airflow. I agree with Chris that if fresh air unit is over powering the kitchen it maybe the humidity giving odd airflow reading (as it is thinning out air in cooling and leaving enough to balance the readings. Just a odd thought. ) Love your video, your vids have help me out a ton...i know bad joke. Keep up the awesome work.
Beyond my experience but enjoying the ride along.
At least they had the good sense to put hail guards on them. Go out to a site and the entire roof is covered with golf ball RTUs. Don't work worth a damn, but they sure are aerodynamic.
You really need a hot water pressure washer with a 1000 psi max operating pressure and a flow of 2 gal per minute. This combo would not hurt anything fin wise and flow enough volume to maintain enough heat to effectively remove the grease. Those condensers will wick away the heat really quickly if your GPM isn't high enough. You can also introduce your favorite cleaner into the system if you deem it necessary.
Also check to see if evap coil is dirty could be a small portion of the air flow issue.
Nice repair video 👍
They named it "Voyager"? A rooftop air-conditioning unit?!!
( to think, someone in their marketing department was actually paid to come up with that )
This may sound strange but Trane called it the voyager because it is ....... The voyage continues... It makes no sense to me either!!!
put a new outdor unit and A coil in a older existing duct system.started unit,found the problem with old unit.,no supply air or very little. check blower wheel.coated in grease and dust.no incline on blades.cleaned fan,what a difference.like night and day!
Sounds like a airflow restriction before the evap coil, either a dirty coil or filters. Could even be inline return grill filters on the registers or a dirty fan barrel.
I’ve installed spiral duct on exhaust fans to keep grease out of the other equipment.
Before seeing what you did as a solution for the kitchen exhaust fan/grease problem, I think I would do a wind screen type shield for that side of the micro channels,
Blower motor amps will give you an idea about how hard motor is working. I would check air flow at the supply and return grills with a flow hood
Wouldn't all the fancy energy saving stuff lower the output air if it detects high static pressure?
BEST 😎 INTRO 🤣 EVER ! 🥳
wonder if supply blower motor, if belt drive, is fully loaded? Maybe bigger drive pulley to increase blower RPM to full motor load, increasing static into main supply duct.
Could you use dish soap to clean the grease off? It wouldnt eat the metal
I've used dish soap before and the bubbles were insane!
@@HVACRVIDEOS Maybe dishwasher detergent would be better since it doesn't have a foaming ingredient.
Most excellent thought and Suggestion.I so know Dawn dish soap has a really great surfactant for Removing the greasy surface tension .But it also bubbles Alot! dishwasher detergent should be better ,i agree!
Thank you, for what you do.
How do you PM’s on walk in coolers and walk in freezers??
I gather you explained the clogging caused by being badly positioned next to the vent and the impact on the units performance and the need for a solution but I didn't catch if they wanted a solution.
I once experienced a greased air exhaust blowing onto the condenser coil... It was a job removing the grease,,, Eventually the customer directed the exhaust air the other way...
Nice intro and great video.
static pressures fairly low and cold supply, maybe the blower isn't on highest speed tap, worn belt slipping or getting slow from weak capacitor. same for condenser fans unless it's all 3 phase or vfd.
looks like one of them head scratching things and it sucking hot exhaust hood air sure isn't helping.
after the other post I heard you mention servicing with an extension being a pain, there should be quick release ones that just latch on and off easily, it wouldn't take but a minute more to service
Was the belt on the blower loose at all?
I was also thinking for the exhaust fan that maybe you could have a custom elbow made and have it throw the exhaust out on the opposite side, just a thought..
Maybe taller exhaust vent, like a couple of meters tall.
Wonder if the motor sheave was adjusted to a lower airflow, therefore not causing high static. Not sure why that would be done other than duct issues. If someone did that, they weren't thinking about suction temps
Well, you said it had a vfd, so probably scratch my idea
Another great video 👍👍👍
Don't know if u have seen it, but I've noticed that the 400 series refrigerant had drier issues. My theory is the poe starts to wax or the varnish starts coming off of the compressor windings.
I think it has to do with high pressure and the poe
What are they called package units and what are they called in different Tonnages?
Also. Are those yellow steel pipes gas pipes like natural gas?
I do mainly residential but I've hit commercial here and there the last 11 years of doing this. I've wondered about the tricks of getting that water out of the micro channels I've used nitro when it's on the ground or just take a lunch and let it sit with the cfms running. You in socal? Scenery looks familiar in some videos.
Woah, 30 degree split, that IS high
Microchannel condensers look weird on the video, probably because of the small hole pattern being really funky with the camera resolution. Always get some funky Moire patterns on the screen.
I make those units. Cool video
What kind of tools are you using to get your sub cool super heat on your iPad? That would be so beneficial for me in the field as well
Good work, Did you check the blower wheel to see if it is full of grease, and also check fire dampers? I have had both issues in the past with both restaurants and hospitals. Thanks for the excellent video[s.
I would check the Drive out put voltage between phases.. making sure blower motor is giving U 100% horsepower output. 👍
what happens to recovered gas?
The supply house takes it and sends it off to be cleaned and resold
Can you see the hz frequency feed back ? Sometime even if drive say 60 they aren’t running at that. It could be what the unit asking forThere are typically two things on drives you actually have your analog input what you’re asking to drive to run it and then you could have a Feedback telling you what it’s actually doing and that 60 Hz could just be what the units being asked to run at
Just a idea
Hey Chris, what is the app you use for diagnosing?
How about a fence inbetween the exhaust fan and the Unit... maybe made of that metal mesh/screen ...
4:45 mark. I think you mean low head pressure. You're never going to trip a unit on high head with the condensing coil saturated with water. Also at that same mark, it appears as though you need the rinse the detergent out of the coil and the unit. No way would I have left the all of the foam in the coil or unit.
Can those soap bubbles damage anything internally?
Hey Cris, what is the app you use for diagnosing.?
My first thought is maybe a sheet metal shroud only on that one side of the exhaust fan to keep it from blowing that direction?
I think the only real solution is a hood extension but its gonna suck when servicing the fan! They get high winds here so it has to be anchored down and able to handle 30-40 mph gusts....
@@HVACRVIDEOS Captive aire makes nice removable windband extensions that will clamp to the existing flat flange on their fans.
If you make one yourself, avoid galvanized, it is difficult to clean.
Sucks is the hood cleaning contractor usually destroys them smh.
Could you put a hood extension on and cut out an access panel on the side not by the ac unit. So you would be able to check the belt.
Great video bud
Great trouble shooting I feel system may possibly be over sized for ductwork
Low static high delta, blower issue ???
Maybe the system needs a little more static pressure? Close up the pulley a little and squeeze out a bit more cfm.
Def LOW on supply air flow,Agreed!
New to the channel, nice vids! What do you use to shoot your video? I do a lot of field work with industrial equipment and the post install videos are priceless, but the quality of my phone is only so so.
I actually use my phone a galaxy s10+
Will you try a steamer on a greasy coil some time?
Which came first, the HVAC or the Vent?
I’m having trouble understanding how you could have a high-temperature split with low static pressure. Low static pressure typically indicates good airflow, so it seems contradictory. I suspect the placement of your temperature probes might be causing the high-temperature split. Additionally, a high-temperature split should affect pressure on both sides of the unit, meaning pressure would be low throughout even if the unit is close to the exhaust fan. I’m puzzled by this discrepancy.
It's actually a Danfoss vfd in a box. Nice VFDs.
Hey Chris, I'm probably talking rubbish , but would it be possible that the exhaust being so close would take out a lot of the flow , so that there's not enough air flow left to be taken by the package unit return air so to speak , if that makes any sense ?
can you use a presser washer ( Electric ) 1000-1200 PSI
You should be sponsored by Groove.
If it wasnt for fly by night installers and Chinese and Mexican made parts our job demand would decrease about 50%. You burped that condenser like a proud dad. Funny stuff.
Great video Chris- Do you think they upsized that unit at one point and never adjusted the air flow?