THE DINING AC IS NOT WORKING

This was a call on their dining room ac not working, it had a tripped breaker and I found an interesting issue.
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[@Samsquanch96]

I know absolutely nothing about HVAC. I have no idea why KZbin recommended this channel but I'm glad they did. I have no idea why this is so entertaining. I think it's the way you explain things so well. I'm subbing.

[@HVACRVIDEOS]

Thanks so much!!

[@RichGT350r]

I Stand Behind My Work!!! ..... Far Behind... So if it blows up, I Don’t Get Hurt! Thanks for sharing! 👍

[@russellhltn1396]

As an electronics tech, something that caught my eye was that line of dirt on the bottom of the main board. Dirt can become conductive, especially when the humidity rises and then you'll get all kinds of weird problems. Just part of how I roll when it comes to big picture, inspecting, and doing it right. I use an acid brush that I've cut the bristles to half length to stiffen them. That and a vacuum cleaner.

[@FerroequinologistofColorado]

The placement of that fire sprinkler by the ladder is just an accident waiting to happen. Great video as always.

[@lwilton]

And I bet it is mandated by the local fire codes. A sprinkler in the top of a chimney to keep it cool.

[@mman454]

l wilton I would’ve expected to see that in his other videos where he shows the roof hatch then.

[@kittyztigerz]

i have seen one guy got his hat caught in it n set off sprinker ROFL easy way get away with it put big cup with duck tape on it that way doesnt get caught on something when ya coming up there

[@alanr585]

Haha, yes, love it! lol each time I saw it in the video just thinking of it and it being caught on video too. I'm glad I didn't choose your trade when I left school but I love watching you doing such an important job in often horrible conditions. Respect to you.

[@graemebardsley-smith4394]

Almost certainly mandated by code - would be here in Aus. So in reality the failure is on the part of the architect providing insufficient space for access (fairly normal from experience) or failing to provide other suitable access -,eg external. That of course brings in a much bigger picture and that has always been the issue with facilities design for engineering services. In the end, it’s the service tech. wearing the problem. I think a cage over the outside of the head would avoid triggering the head but might reduce available space too much. Another two inches on the access and much better!

[@arthouston7361]

As soon as they came out with the first Prodigy, I learned to replace every controller with a new display as well.

[@rickharris4258]

Super videos, 50 years in our trade but still learning. I will never forget my instructor so many years ago saying for the first five years you know nothing. Keep safe.

[@PeterParker-tb7ce]

Looked up Spec on that VFD (FR-D720-100-NA). It looks border line in it's sizing. It's rated at 10 A up to 122°F. It should have over temp protection. But from all that dirt I see from the cooling fan means the heat sink is most likely dirty. Thus reducing it's cooling capacity. If this is an common issue look at replacing them with the FR-D720-165-NA model. It's rated for 16.5 A.

[@lwilton]

It's also probably running closer to 150 F ambient mounted in that unit on the top of a roof in So Cal. You can see two of the main filter caps have died, and this was quite likely from the prolonged high temperature soaking. I strongly suspect those caps failing was the root cause of the VFD failure, not a (stupidly) borderline current rating.

[@stephenhunter70]

@@lwilton Not to mention dirty supply from all the contractors and motors etc in the various AC's etc/ But you are right the caps are not going to like sitting out there in the hot sun all day at 150f/65.55556c. That's going to be a bit hot even for the micro controller inside of the VFD too. I'd go as far as 50% de-rate them, go find one that will supply the required amps after 50% de-rating it.

[@443DM]

@@lwilton Seems like a business to re-solder new caps.

[@analogmoz]

I'm going to pay to put up a bunch of upside-down billboards in Chris' service area and watch him slowly slip into madness.

[@blazeeisner9620]

Hey Chris. Great job and video again. The haters sometimes criticize you for using tech support. But we mechanics don’t know each and every machine. The folks with tech support many times make us look like heroes. When I was in the field; I loved Lennox units. At Emcor when I was there, we took care of a lot of National accounts. Many times it was a hassle to deal with them but bottom line; they put food on my table. Most of the Target stores that I serviced in San Diego county had those Lennox boxcars. I hope that your business is doing excellent. Stay safe and careful out there. Have a great Thursday evening with your family. God bless.

[@lwilton]

Pretty fair guess about what happened to that unit: Looking at the VFD innards, it is immediately obvious that two of the main filter caps have failed. Others may have also failed, but those two probably were enough. They were probably bad enough that they were supplying AC to the VFD logic when it should have been DC. This probably wouldn't have damaged the chips, but it trashed their operation, and they got completely confused. Somewhere in their confusion, they turned on two or maybe all three phases at once, shorting the line across the power MOSFETs in the driver part of the board. The result was a lot of black greasy smoke and shrapnel all over the inside of the VFD. A lot of nice greasy conductive smoke, probably along with a nice hot arc for a very short time. Probably the arc migrated from the power MOSFETs into the logic chips. From there it fed back along the control lines and momentarily put 208 onto the logic of the main control board. The VFD control may be partially isolated, but not enough so. The short pulse of HV didn't completely smoke the control, but it was enough to confuse the heck out of it, and possibly fry some logic as well as wiping out the flash/EEPROM memory in the unit. You are probably right that having that VFD in a more climate controlled room would have preserved it. I suspect if you put a recording thermometer in the VFD case you would find that it is way over the max continuous operating temperature for a good part of the day in summer. I'm not an air conditioning guy, so I might seriously consider going to Lowes and getting a 5000 BTU room AC and and ducting it into that electrical area of the package unit. Might be real cheap insurance. (And I'm sure you can think of some more reasonable idea.)

[@zjeepgozweeln]

The better designed units have a hole to leak a small amount of conditioned air through the controls compartment during operation.

[@joelacosta2082]

@@zjeepgozweeln a little suggestion put the vfd in the blower compartment it's colder

[@Magiobiwan]

Joel Acosta then you run into Condensation issues with the VFD.

[@lwilton]

@mark robertson I'm not sure if that is a deliberately snarky comment for reasons I don't understand, or if maybe the comment means something completely different that I don't understand. What does describing a probable VFD failure cause have to getting venereal disease?

[@dashcamandy2242]

That opening clip... I cringed so hard. Brought back memories of working in a certain home improvement chain's local distribution center. A sprinkler head was RIGHT next to the warehouse racks, and there were many than occasions where we had to shut down and evacuate because someone on powered equipment had taken off the head and triggered the fire alarm. I kept suggesting to anyone that would listen that we should install a small cage of rebar around it to protect it from impact, but nobody cares what the fireman's son has to say about the fire alarm system. OOOF, those exploded capacitors on the VFD are definitely the cause of the tripped breaker! I wonder if they failed due to high temperatures on the roof? High temps cause the dielectric to breakdown and the caps then basically become shorts. Mitsubishi also had an issue with bad capacitors in some of their cars' ECMs in the '90s because they used a cheaper brand instead of their own parts - they dried out under the harsh temperatures inside a car and failed. As you said, putting the VFDs in a cooler environment will extend their lifespan. Judging by the incredible scorch marks inside the dead VFD, I guarantee some HV arced over to the LV sections, if I had to offer a theory (much simpler, but similar to I wilton's theory) the faulty caps became dead short, high voltage arced to low voltage sections, and from there basically grenaded the daughter board and probably parts of the main board.

[@coffeecoffee5914]

shaming for calling for tech support is as bad as those that throw out the wiring diagrams

[@alexex3030]

God bless you for working at so many restaurants, I imagine it’s like pulling teeth at times convincing people they actually need things repaired/replaced

[@Eddy63]

Man , this was a good vid Chris ...Love the little Prayers before start-up ...Lol ... Very bourbon worthy ...

[@sebastiannielsen]

suggestion: When filming the prodigy boards - try using a slightly longer shutter time (in most phone models if you use a phone to film - have a "advanced" or "pro" mode to set shutter). You might need to reduce apeture tough. If your phone or camera allows saving profile, try getting a good profile for just prodigy boards, and then save it as 2 profiles, one for "normal" filmning and one for "prodigy". Play around with the camera settings - should be pretty easy if you have a prodigy board at home, until you get a nice view.

[@chakflying1]

Usually wouldn't work as the outdoor sun is too bright for a slower shutter speed. We use ND filters for that, but finding one for phone cameras might be difficult. An easier way might be to just put sunglasses / welding goggles in front of the camera and let the auto exposure adjust.

[@pepsicolachao4537]

Remember this place where the main exhaust fan was replaced?

[@HVACRVIDEOS]

Yep

[@johankling9994]

Damn, you could've had a real problem if you broke the vial of the sprinkler.

[@OcRefrig]

At a minimum that sprinkler should have a wire cage around it.

[@johankling9994]

@@OcRefrig that would seem like a smart thing to do.

[@jazbell7]

The environment for electronics in a unit like that is terrible, comparable to an automobile. High heat, very cold in winter, vibration and lots of dirt. Not to mention lots of big motors being stopped and started, causing power line transients. VFDs are now everywhere, clothes washing machines, garage openers, residential A/C.

[@mikeydk]

Even fridges got VFD's in them now. Pretty cool (no pun intended), I can never hear my fridge running under normal circumstances. Only time I can hear it very low, is if it has been powered off, or a lot of new stuff has been put into it.

[@m8onethousand]

On the bright side, the epoxy (?) coating on the new M2 seems thicker which should help a bit.

[@OrangeRAZ]

Most units have vent holes that keep that compartment warm, some times

[@fortfun46835]

Drives don't care about cold except maybe condensing water. However, in the heat you need to derate those drives. I would have gone up a larger drive if that was the second one blown. We use a lot of those Mitsubishi drives and I've never seen one fail like that. Surprised that if they are only using two speeds they would go through the trouble of a variable output. Just set the two different speeds and use the RH and RM input to select.

[@443DM]

Stupid to have a VFD at 59hz. It should just bypass at that point, run at 60hz and let the VFD electronics take a rest.

[@thephantom1492]

With a proving circuit, you now have 3 possible states: - Open: wire is broken - Shorted: Wire melted or detector tripped. - Supervisory state: All is fine. How it often work is with a simple resistor. Basically the resistor 'soft short' the wiring at the end of it. If the panel see the resistor, then the wiring is intact. Open then something is broken, and sorted it mean it tripped or the wire shorted/melted. Some system will use two resitors, one end of line (the first one) plus another series one with the detector. Now you can have 4 states: open, close, EOL resistor or the tripped resistor. Those can therefore detect between the shorted or tripped condition. Those can help to avoid some nuisance alarm due to a nail in the wiring.

[@feelingtardy]

gotta love tech support. you can ask the same question to 3 different people and get 3 different answers sometimes

[@matthewsykes4814]

It's the worst thing to come into a fault half way through the fix, stuff's been removed and the bolts have wandered off ..... great to see just that little bit of detail. Makes life so much easier, especially when you've bolts of different lengths.... that's always fun. I've the same issues at work, you can't fix everything first time. Sometimes you get lucky, most times you open up a whole can of worms....... it's why I like my job. It's boring for the most part but there are moments of happiness when I'm sorting problems out.

[@Athstavr24]

Hey great video very informative but did you actually remove the balloon??😂😂

[@HVACRVIDEOS]

Yeah we pulled the whole economizer out and cleaned them all out there were like 4 in there, it just didn't make the final cut

[@semifavorableuncircle6952]

Why the hell do these units have no fuses for just about anything? Normally there would be fuses or breakers for the drive, motors etc. Looks like electrical regulations in the US are really lax about this. No surprise the VFD fails that way. When these blow here, even with 400V mains, the input fuse blows and there isnt any damage beyond the power module and it usually can be repaired.

[@riccardoz2953]

it should have also a self protection cyrcuit.. was a mitzubishi if i didnt see wrong.. how can fail so badly?

[@semifavorableuncircle6952]

@@riccardoz2953 Normally VFDs dont have any internal fusing and require external, properly sized, current limiting, fuses.

[@semifavorableuncircle6952]

@Timothy Salomon Idk about HVAC, in my field of industry, we frequently have to deal with really old, hard to replace parts and often go for component level repair, sometimes going as far as to qualify as re-engineering.

[@russellhltn1396]

Fuses are about protecting the wire. In this case, I doubt if any amount of fusing would help much. The protection circuit has to allow enough energy to run the fans - which is more than enough energy to go "bang".

[@russlehman2070]

Kind of looks like the VFD IS the fuse. Why sell a $5 fuse, when you can sell a $50 VFD . Or whatever the acctual prices are. I just pulled those numbers out of the air.

[@uxwbill]

Just like the switchmode power supplies to which they're very closely related, the active components in those VFDs have almost no tolerance for errors in their controlling circuits. I'm always fearful of those sprinkler heads when pulling network cables and putting up wireless APs, that some absent minded movement is going to trigger a major disaster through the whole building.

[@watermanone7567]

Nice job: You can't beat the older style units that have only relays that operate the stages and systems. Sometimes the new tech stuff cost more that it saves. Thanks for the video.

[@gordonrichardson2972]

Waterman one Watching this video was fascinating, but also a infuriating. Why so complex? KISS...

[@DocNo27]

@@gordonrichardson2972 thank our "environmentalist" buddies. Don't get me wrong - I'm all for conservation. But how about conservation with some common sense that's not completely divorced from reality?

[@OcRefrig]

@@ItsMrAssholeToYou 👍. Agreed.

[@russlehman2070]

Yeah. I'm not in the industry, but I have to wonder if that VFD and all the circuitry that controls it is really more economical than a two speed motor controlled by relays and contactors.

[@hgbugalou]

@Sean That is throwing the baby out with the bathwater. Nothing wrong with using chips and such where it makes sense. It just doesn't make sense to use them for ~5% energy savings while sacrificing ~25% in the reliability.

[@TheLenaweeTrekker]

Thank you, for this video. I have not seen these here in Michigan, yet, but given the energy regulations and the closing of coal fired plants, it's only a matter of time before I have to deal with these VFDs. Thanks to you, and your experience, I will have a leg up. Thank You.

[@neon-john]

Real electrical engineers know how to do multi-speed motors with no electronics. This gratuitous electronic is being put in there simply to generate service calls. True variable speed units like the mini-splits I installed in my retirement cabin are a different matter. Even then the chicoms are running the power transistors at absolute max rating which is why one driver board has already failed.

[@FreshRoastCoffeeOhio]

i know nothing about hvac at all, but these vids are just very interesting for some reason. keep them coming

[@haydenuk02]

Who in the hell put a sprinkler right in the way of the ladder to the roof excellent work and thanks for the awesome content stay safe and take care

[@Dont-come-at-me-24]

Why not just use a two speed fan ? So for first stage it runs at 50% speed and then 2nd stage 100% would be a lot cheaper then a VFD

[@irfp460]

Lower power, less energy efficiency and depending on volume probably not even cheaper.

[@38911bytefree]

When something blows up like this, probably the lov voltage got shorted to the high voltage side as a result, and tooks with t whatever is connected to it on the LV side. Nice they tear appart as explode, so you it will catch your eye instantly.. Good job man, seeing a pro in his trade has no price.

[@chieft3357]

I see taking a picture with your phone of the elect control panel helps to make sure the connectors go back in the proper place?? I hope you have a employee with you so he can learn from what you are doing. You are doing so really good troubleshooting right now. Nothing like hands on training for the troops.

[@SalDarkSeed]

Anyone else just enjoy watching him fix stuff?

[@HappilyHomicidalHooligan]

19:33 And that right there is likely what killed the old VFD... It got dirty, overheated and went BANG! These things really need to be cleaned regularly, once every 6 months just isn't going to cut it. Clean them every 4-6 weeks or you'll likely severely reduce their Lifespan...

[@lilpbass]

Lennox suck. Over engineered junk. Basically the Mercedes Benz of ac.

[@caerusdharken57]

I've been watching your Videos for the past two weeks now, even though I'm not even remotely connected to HVACR I'm an electrical engineer, but I picked up a fair bit and after reading up on some terms that meant nothing to me like superheat etc. I even start to understand how and why you do things. So you do a pretty good job on explaining and methods. Probably will never put that knowledge to any greater use since the HVACR guy at our company didn't even take me serious as I told him that it sounds like a bearing in the compressor is about to die (compressor died 2 Weeks later, took them 3 months to get a new unit installed, industrial carrier cold water circuit, those roof direct air units are very uncommon in europe) but it never hurts to know things outside of your job, so thanks for providing :)

[@sampantiliano]

I love Lennox rooftops but their supply houses and tech support are absolute garbage... 🗑 They never have the part in stock your looking for and at least in North Jersey the guys at the supply house are slow slow slow and rude to boot.

[@Anonymous01416]

Lennox supply house employees are trash and ass holes!!!

[@marknaravas318]

Don’t worry about the sprinkler. I’m a truck driver and had a load to an enclosed strip mall that had a height hog 13’6.5”. My truck is 13’6”. The day before they had lowered the sprinklers 2”. I took off 4 sprinkler heads; it looked like a Roman fountain goin off on the top of my trailer. It was quite scenic. Not!

[@wiedehopf9068]

Feels like those VFD drives should just have versions with more fans and changeable filters. That way they don't get as dusty inside and should last a lot longer. For this application having them be very compact doesn't matter. Maybe have an attachable intake fan + filter? But that would reduce sales for the VFD guys so... not sure if that would happen ... also maybe that use is too niche for those drives?

[@thenewsshow]

it is interesting, I don't think I have ever seen a running VFD that was not full of dust.

[@James_Bowie]

An alarm code (46) with no description? Hey Lennox: how the hell did that pass software testing?

[@Jonoth]

I've worked with Allen bradley drives that have had "unknown" errors they their tech support didn't even know about

[@James_Bowie]

@@Jonoth Clearly these manufacturers don't give a damn about testing.

[@MattTrevett]

I don't know if you (or anyone) will ever be in this situation again, but it looks like the D700 series is able to have a minimum frequency programmed in relatively simply, so instead of reinstalling the contactor while you waited for the board to be ordered, you possibly could have set a minimum frequency for the VFD which could have saved some installation time.

[@gregpfister6991]

Maybe I'm showing my age, but why not a multi-tap motor instead of VFD? With all the cost necessary to keep these failed boards and modules working, it would be cheaper for a multi-tap blower motor. It would only take a two contactors with an interlock - when calling for one, the first contactor kicks in and delivers to one set of windings. When the call for second stage, the second contactor is engage, releasing the first, and power is delivered to the next set of windings. Not rocket science, and don't go "boom". Worst that can happen is either a winding short, short to ground, or shorted contactor. Contactors are considerable cheaper to replace than a VFD drive system.

[@44R0Ndin]

It's all in the name of efficiency, apparently using a VFD on the motor can give you a better power factor or something like that. The real problem with the VFDs is exactly as Chris mentioned in the video. They're putting them outside when they're not rated for that. They need to be in a conditioned space. Were it me, I'd mount the VFD and the control board in a space that was in the airflow from the return air duct to the blower housing. Easy way to keep the electronics inside the RTU and still have them in an environment that's much more conducive to longevity of the unit. I think some other brands do this already, I guess Lennox hadn't caught on yet when this unit was manufactured.

[@gregpfister6991]

@@44R0Ndin If power factor is a big issue, then run an synchronous MG set. Gives you the best PF, plus it saves the electronics from line bumps and spikes, as long as it's not undersized. I wouldn't be surprised that if you ran the numbers with 5+ units with VFD's vs no VFD's and synchronous MG set, the MG set would give you a better ROI.

[@ke6gwf]

@@gregpfister6991 a vfd is cheap, and programmable. Meaning that they can adjust airflow with programming, for air balancing, etc.

[@gregpfister6991]

@@ke6gwf VFD is CHEAP, in comparison to a multi tap motor? Again, I believe that if you add the costs up, you will find that VFD is NOT cheap over the life of the equipment. Further. when you look at the inherent dangers of operating mosfets (as we see in static UPS's), the cost associated with protecting them and the destruction caused when they do fail it's just not worth it. In this video alone, we see the example that one board causes the VFD to destroy itself completely, and the recommendation to replace the main board and the cost associated with THAT. Just because you CAN do something doesn't mean that it's GOOD. In my years, I've seen many "advances" in technologies, and have been at the forefront of many of them. However, ROI is king, and always should be. If a product is going to eat itself every 3 years, as apposed to 10, I'll pay 50% more for the product that will last 10. Why? Because of the cost associated with the downtime, loss of business, how costumers perceive the outage, cost of repair, etc.. You have to look at the big picture, not just "new tech, so cool".

[@Zyxlian]

@@gregpfister6991 I'm not in the trade (I'm in IT/programming) but, and correct me if I'm wrong, aren't VFD's supposed to be used for power /curves/, and not just 2 stages? A VFD in this just seems like crazy overkill if all you need is 2 power stages. Even if you had to have 2 "programmable" stages, it seems like there could just be something like two variable resistors (I don't know the correct pieces of hardware) that controls the amount of power for each stage, and a relay to change between them.

[@sherwinalvarez7365]

Yo Chris i just wanna say thanx for all your hard work and vigilance bringing us these videos. I enjoy watching you making it a little easier for us new guys. ✊🏽

[@GottSegneDich]

Check out the shit-stain by the VFD at 4:19 😬 Edit: Currently a 4th gen locksmith but these videos have me thinking of a career change. Edit #2: It was dust. Ignore my ignorance.

[@jhp110]

Great video amazing how complicated these units can get to meet energy consumption requirements. I’m an electrician and what I find odd is the fire alarm supervisory circuit should not be dependent on the units power supply, the supervisory power should come from the fire alarm panel/sub panel and should just monitor the continuity of the alarm wires and the smoke detector it shouldn’t matter if the unit has power or not to cause a supervisory alarm. I think you may have had a surge on the system power side that may have damaged the board maybe that unit was the closest to the surge is why it was the only one effected. Just my two cents, great video and great service skills to get that unit working temporarily.

[@jojomorgan8556]

Merch is our way of supporting you and advertising your channel while getting something cool in return love the videos keep it up

[@carlosedwardos]

Those black electrolytic capacitors in the VFD are toast! - see how puffy they are?

[@RichMelvin]

If you turn off the shutter in your camera (or set it to 1/30 second) the LED displays on the units will display properly.

[@k.sullivan6303]

Nice work Chris. Good job on getting things up and running temporarily with the contactor.

[@wwolf771177]

You forgot to flip the contractor cover over. 😂🤣😂

[@elijahtalbot5288]

I agree that is a stupid spot for a sprinkler

[@CM-dt1et]

That's a nice rooftop!

[@samueleddy3112]

Seems like we’re starting to go from HVACR techs to computer techs. I’m on the ice cream side and it’s always one board doesn’t communicate with the other and now I use my meter more than my gauges.

[@lwilton]

Watch the "South Main Auto" channel for a little bit and you will see that car diagnostics and repair are now all poking at a computer screen and only occasionally twisting a wrench. Its pretty much the wave of the future (present) for most all trades, I suspect.

[@ischmidt]

@@lwilton Funny you reference SMA. On this video when I saw the blown-up VFD I said "Well there's your problem, lady!" in my best Eric O voice (which isn't very good).

[@thenewsshow]

Same thing happened in the telephone industry... went from hardware debugging and repair to all software and just replace the sets when they go bad over the course of only like 10 or 15 years. whack.

[@OcRefrig]

Wilton - sma rules.

[@RedAzukiCake]

The reason why the camera can't see the displays is because they're doing something called multiplexing. It's much cheaper/less wires to display certain segments of a display at a time rather than every led at once.

[@russellhltn1396]

A lot of that is the camera is doing a high shutter speed due to being outdoors in the sunlight. Put a neutral density filter on it when you're outdoors and I'll bet the LED start looking a lot better.

[@michaelsassenus3154]

“stand back man” lol, made me feel like I was there on the roof with you,

[@marty0715yt]

Typical jumpered system running , install the new parts, system down, re-install the parts when it worked. Like performing a 3 hour Field Modification Instruction and it don't work. Spend another 3 hours putting it back to to where it was when you walked in. Regretting going back to attempt the "UPGRADE" again. We used to make crap work by cannibalizing new and used parts to get out of Dodge! Great save.

[@zjeepgozweeln]

I think VFDs are great when they're of good quality and properly installed. They allow you to do so much with just one motor. Low demand or a need for de-humidification? Low and slow... High demand? Full speed ahead! You can maintain static pressure or airflow based on feedback... the options are endless. VFDs typically are set up with 3 I/Os. start/stop, analog speed (or in this case a pre-programmed 2nd speed), and a dry contact for alarm. Of course you can configure a lot more I/Os for other things as well. The better units can be configured for a lot more. Alas, here you see what seems to be a poor implementation. 3 compressors and other equipment sharing the same space on a roof that can reach extreme temps, baking in the sun. Sounds like a recipe for disaster if I've ever seen one.

[@gordonrichardson2972]

zjeepgozweeln Fine summary of a waste of good technology!?

[@Colt-wr6wx]

Damn don't you hate having to install what you just installed. I rebuilt a 208v fan motor today n the wheel blower assembly was all jacked up and had to rebuild with new blower assembly. No biggie just frustrating

[@rmarkesteijn]

Small tip from a hvac tech taken a brush and brush the dust from the circuit boards dust can make a short and with the low control voltage that the board needs can give strange problems VFD went due to bad capacitor nice video again Chris

[@shentx]

How tempting is it to just leave the contactor in and call it a day?

[@deineroehre]

Hmm, energy efficient switching of two speeds would be easy! Mr Dahlander from Sweden developed the solution for the two speed Problem already around the year 1897. VFDs for only two speeds are nonsense and tend to fail if mounted in this dirty cabinet, fanless design of VFDs would be possible and could help, but cost a fortune.

[@DocNo27]

There are three speeds on this unit (it has three stages)

[@deineroehre]

​@@DocNo27 Wouldn't it be in this case sufficient to use the lower speed for stage 1 and the upper speed for stage 2+3? I don't know these energy efficient laws, but given a VFD has some efficiency losses either (otherweise he wouldn't need cooling with fans), it would be sufficient to use 2 speeds and still be efficient. Or using an tap on the motor for the less used stage, fans are controllable by voltage and this is reliable and archived with rather cheap contactors and some brain instead of these VFDs. Just saying! There will be engineers who already thought about this issue and management who disturbed this thinking with costsaving. ;-)

[@HVACRVIDEOS]

Yeah the unit is setup for two stages, the second and third compressor turn on with the second stage

[@DocNo27]

@@deineroehre I don't necessarily disagree with you on the real total cost of ownership (TCO) for some of these hair brained ideas, but you can thank our pandering politicians proliferating ponderous energy policies that sometimes force these ridiculous design decisions. It's probably a wash in the real world, but for energy star they probably don't factor in things like cost and e-waste from the 10 VFD units an AC unit like this will consume over 30 years, yet they can meet some efficiency mandate that looks good to the pencil pushers that are often divorced from reality but instead seem to live only in this magical place where Murphy really was an optimist after all. Another perfect example of regulations gone mad - my parents Acura RDX kills the engines at stop lights. They live in the desert southwest. What the do you do for AC with that kind of a system. It's supposed to stay on if it's hot but the engineers idea of hot is completely different from a sane person. Plus it introduces wear and tear. Yeah they oversize the batteries and starters - but it still increases wear. It's amazing the number of people who don't religiously disable the daffy system and let their cars power off and on every time they stop, then have problems (often miraculously just outside of warranty) and then complain. I'm hoping someone comes out with a ROM or other hack to permanently disable it cause it's dumb to have to push a button to start the car then push another to keep it running every time you get in :p I know they did it and don't let you disable it because it probably let them claim a few MPG on the fuel efficiency regs. And just think what kinds of even dumber crap we would have if Trump hadn't canceled the completely unrealistic Obama mandates. But I digress - a little. It's all related.

[@ACHVACTAB1]

The new Vfd-Bad Board scenario : Maybe just program the Min-Vfd speed to 100% i.e. same as the Temp Contact ,, This way it makes no difference what the boards calling for the Vfd runs 100% no matter what !!

[@EnderMalcolm]

Gonna be honest, these VFD drives seem to be more trouble than they are worth. If they keep blowing up like this some day they are gonna start a fire or some other bad thing. I can just imagine the issues if you have a unit that's not grounded and the VFD blows and shorts to the unit casing. Some poor chap gets up there late in the evening to fix the thing and it blows up in his face. That might be a stretch, but for the energy cost you save with these VFDs, it doesn't seem like you'd really save anything. Constantly having to have techs come in and replace them, they go out on backorder, all that hassle when you could just bite the bullet on the energy cost and run a relay or something simple. I get that it's regulation in some places because of the electric grid and all that, but it just seems like such a mess dealing with these units. Just my personal rant and thoughts.

[@stormeagle28]

Why the US manufacturers don't know Dahlander motors? A VFD is only good if you need full variable speed control or a speed above the 60Hz rotating speed. For a two-speed drive only, you can easily use a Dahlander motor with old-style contactors and you will never have a blown-up VFD.

[@HansakaChaturanga]

@HVACR VIDEOS if i face this kind of situation ,most of time ill remove pcb stuff and modify the controllers in my way,which could save lot of money and client also satisfy,VFD u can controle with out expensive PCB .

[@Evergreen64]

NOBODY should give you crap for calling tech support! The ONLY people that know how the unit is programmed, and it is a microcontroller in there, is the manufacturer. If I have a programable microcontroller in something I can tell it to do anything I want in any way that I think it should be done and I don't have to tell anyone how it's programmed.

[@chriscooley906]

Nice video Chris, you covered the entire cooling operation with this call, I would recommend you get a pair of MAGJUMPERS instead of skinning the insulation on the control wires, Thanks for sharing bud !

[@Moalho]

Great job, I have learned from you something about VFD troubleshooting and how to jumper it out ( temporarily) … Thank you for that, I would really like to know how you discovered or recognized the two control wires that should be hooked up to the contractor’s coil ?

[@mechanicwarrior20]

It would of been really nice if that RTU came with a VFD Bypass option! That would of saved you a lot of trouble! I am happy that the customer didn't flip out at you! I hate it when you have to go back to the customer multiple times telling them they are more problems then what was previously quoted? But It's part of the HVAC&R Field! Great Video!

[@CHOMAHOMA]

Good video. I really liked this one and I agree with Russell's comment. I wouldn't know what to charge for a type of work like this when it takes different trips plus replacing very expansive parts. Thank you again for filming this type of work. It is not easy do film and work at the same time.

[@BillyN31]

I’m just curious, when you were looking for 24v to energize the contactor, couldn’t you get it from common and G off the terminal port?

[@1shagg420]

I really really really hate this proprietary controls. Lennox, Aaon, etc , my God they suck. Those Aaons require a special plug in adapter just to properly diagnose problems.

[@teatrolites3446]

I honestly don’t understand why people dislike videos. Like just don’t watch it if you don’t like the topic.

[@rubenrojas8632]

Thank you for the video. The company Forgot about maintenance. the new Units Have More Electronics Parts the require maintenance.

[@knockitofff]

17:45 good call, looks like Irish skin? that shit's made for dark pubs, NOT sunny rooftops LOL

[@Rewind_Start_Over]

The sprinkler in that location does suck. The worst for me is when the hatch hardware fails or someone removed the hardware including the spring. Now you have a hatch that doesn't want to open or better yet on your way down the hatch comes crashing down and about knocks you out. Worst case scenario is that it knocks you off the ladder. Which brings me to the most disturbing part. You report the problem and when you come back months later it is still broken. Why is it that people wait until somebody gets injured or killed before the problem is addressed. Ok, i feel better now...... Had to get that one off my chest. Btw, are these videos being filmed in SoCal?

[@ninamcclure2193]

I forgot to say, I hate it when I call tech support and get a foreign person with broken English lol. I don't have a problem with foreign people by the way. Just hard of hearing and cell phones don't go together well. Thx again.

[@ares3914]

Dont clinch to hard lmao, you may squeeze something out that can ruin your day and underwear. I'm glad you called tech support. I always tell other techs is necessary on some of these components. And boards can may have improper voltage but current is constant so that may keep board running but not doing what its specified to.

[@ninamcclure2193]

I'm betting that was a cheap fix😁. Thx man that looked like a stick booger. Bet you lost a tad bit of sleep on that one, I know I would have.

[@cranbers]

I take it you are in AZ? or somewhere that gets insanely hot in the summer. That VFD drive has a fan in it, and its sitting outside on a roof where it can get 120 degrees in the summer? Imagine how hot that "drive" gets im surprised non of those electronic computerized components melt..

[@jimgill5706]

That is an insane sprinkler head placement.

[@majstealth]

"error 37... ERROR 37!!! WHAT THE FUCK IS ERROR 37, AND WHAT ARE THE OTHER 36!?!?!?"

[@zarnaihjeneborra9292]

You're great man i learn lot of you thank you for your videos i hope my skill and technical experience it's getting more improvement to learn kind of this jobs and ideas, keep it up my friend.

[@Mrcaffinebean]

Well that was I interesting, the VFD adds a few challenges. But now you know what to look for next time they fail.

[@mrbyamile6973]

I think I would have stuck with the contactor, needed overload protection though as the VFD provided that. Way to hot inside that compartment for a VFD as Chris eluded to when he mentioned the dust.

[@doctorjohn-burgtekie]

Fire sprinkler head is right were it is supposed to be. Fire sprinkler plans approved by the professional engineer of the fire department authority having jurisdiction.

[@travishamilton1659]

Chris you're awesome man! Way to find the problem then find a temporary solution and then come back and fix it totally. Awesome video man keep up the great work

[@OldePhart]

As for the VFD, the caps are swollen, common problem over time and with heat, dirty fan would indicate that's a possibility. The destruction can also happen in startup when the spare VFD has been on the shelf for a long time (years) and the caps lose their polarity. You have to "reform" them with a slow introduction of the supply voltage. That is far less common but it worth knowing about. Another advantage of the VFD is that they don't care about the phase rotation.

[@Anonymous01416]

I work on a lot of Lennox units and I haven’t ran into a Lennox unit that didn’t have a blower motor contactor to by pass the VFD incase it took a shit. Majority of the drives I see are inside by the blower motor.

[@jasongirvan6729]

I just love how the main power cables are coming thru the box without a bushing but you never addressed it either. Did you noticed?

[@IFIXCASTLES]

Could have a brownout. Had a store where I was constantly replacing burned out 24 coil contactors on the a.c.. It turned out the feed lines to the store in the ground were effed up.

[@ForgottenLore]

It would be very dumb if you had to replace the front panel, it should literally be a dumb display board and buttons.

[@OcRefrig]

Whenever You Are Changing the Air Filters Those vfd's & circuit boards Need Blown out with Dry nitrogen too. I Have 2 - 50' - 1/4" Yellow Refrigerant Hoses that i use. Air hose can work too. I use the same hoses to Fill the Tires on my truck.

[@neon-john]

Dry nitrogen isn't needed for that. Ordinary compressed air passed through a dryer is more than adequate.

[@RubenKelevra]

If you expect that a system has no power it's actually better to use the NCV function of the multimeter, additionally to checking AC voltage with the leads. It makes sure there's no backfeed from a different circuit you didn't expect.

[@byrd203]

I agree that was the stupids place to put a sprinkler head but also you should have got a rope tided it to your bag and climbed up to the roof then pull your bag up on the other side away from the sprinkler head

[@mjmej4734]

Can u do a video on vfd. Your videos are very good and helpful. I have been on the refrigeration side and now find myself on the ac side due to covid.

[@RoboSkyrat]

Impact rated/bashable screw drivers are the #1 tool in any tool bag.

[@davidl2650]

VFD needs good venting otherwise they can overheat and blow, generally they should be installed outside with a cover for good ventilation

[@OcRefrig]

At a minimum - the door should be ventilated with louvers in it. A simple fix is install a Return air grill in the door with a rain shield 🛡 / piece of sheet metal inside door.

[@thornmountain8129]

Just waiting for tech support to tell you to change out the whole unit....😂😂😂

[@ehsnils]

To me that looks a bit like the damage you could get from a lightning strike. But wouldn't a VFD also require a control over both incoming and outgoing air so that the air balance is kept in order, so one for the incoming air and one for the outgoing air? Having the VFD in the unit makes sense to me as this would be close to the control board and the load - minimize the amount of wiring is usually a good idea and makes it easier when trying to find problems. But I agree that the electronics should be a bit more protected so that they don't accumulate dirt or bugs.

[@66bigmike]

i dont know if anyone seen but at 12:12 just above the blue wire with the yellow connector on the contacter, there is a spark i only seen it that time and no other time