# Brownouts from our chiller



## StradivariusBone (Mar 17, 2020)

So a while back our building had a new chiller installed. Since then we've had periodic brownouts on the order of a couple to several per hour. We did a lot of troubleshooting and determined that the outside building transformer was fine, our county electricians put a really neat Fluke meter on our building mains to chart the voltage drops and found that they were occurring. We have a sister building that also got the same chiller upgrade but does not have the brownouts. It's enough to occasionally reboot a computer or sound board, which are all now on UPS. It seems to coincide with the compressor kicking on at the chiller. I've watched the lights dim at the exact moment the compressor motor starts up and the chiller shows a persistent alarm for the second compressor having a low current. They claimed it was a flow sensor switch that was faulty and they replaced that part, but I'm given to wonder if they were unsure of the definition of current.

I've heard of issues with loose lugs causing problems like this when a load is applied, but I'm getting ready to push the county to work on it again. Has anyone had a similar experience? Sorry if this is better suited in the electric forum. It seems to me to be more of a facility issue rather than one of lighting and electrics.


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## SteveB (Mar 17, 2020)

Sounds like they undersized the feeders on the compressor system. Likely as well miscalculated the existing load on the system. Possibly the utility company never upgraded the feeds on the street and they just went with what existed ?. Our local provider is Con-Ed and they routinely underfeed supplies all over the city, is why the buried feeders are always failing catastrophically and blowing up. This might be a problem getting corrected as utility companies hate being told they are wrong.


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## StradivariusBone (Mar 17, 2020)

Well the whole chiller plant is fed from the same main panel that our building is fed from. As far as I know they didn't replace the feeder when they swapped it out, but we never had this issue with the older chiller plant. I'll mention the feeder though. It's possible that it might be damaged in some way, we have had issues with our underground conduits and lightning damage causing all sorts of electrical gremlins throughout the years. A nearby school with an almost identical building got the same chiller and has not had similar issues.


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## BillConnerFASTC (Mar 17, 2020)

I feel like you need an electrical engineer on your side.


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## Ben Stiegler (Mar 17, 2020)

Can you compare the specs on old vs. new chiller to understand if the load has changed? If not, may point to an installer issue .. loose lug, etc. if new chiller draws more, even if it appears to still be under the panel limit, then the search scope expands ... upstream resistance at a splice, breaker, etc. or degraded conductor.

Not to be confused with an inebriated conductor, who caused me to lose interest in my college orchestra.
Good luck and keep us posted!


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## Dionysus (Mar 17, 2020)

Have you had your Power Factor checked not just on the unit itself but overall?


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## StradivariusBone (Mar 17, 2020)

I can't speak for the old chiller but the new one has info here-



I know a little about AC motors and how the current draw will be greater when a motor starts from the inrush of current and then stabilize as it gets up to speed. The brownouts are happening as compressor A turns on. From what I was googling, the LRA is the locked rotor amps where that current draw would be highest. It's interesting that the two compressors have different ratings, I figured they'd be matched and duty cycled, but maybe the additional one is only activated at peak use and hence why it's a smaller system? Perhaps the low current alarm on B is when that second kicks in as the other is already running and there's not enough current available, but it's quick enough where it won't trip the breaker? What I'm curious about is why there are two numbers for the LRA. 930 amps is more than the building's main switch is rated for. Granted, that inrush would be like a second I'd wager, but that's a lot of current! 

Anyway, the catch is there is an identical-ish building with an identical chiller that does not have this problem about 30 minutes up the road from me. So I'm inclined to believe that it's something unique to my building and not necessarily a mismatched chiller plant, though I'm prepared to be wrong of course.


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## StradivariusBone (Mar 17, 2020)

Dionysus said:


> Have you had your Power Factor checked not just on the unit itself but overall?



Maybe during the study? The main disconnect has a display that is indicating around .85. It would jump to 1 randomly and float up to .90. I don't know how accurate that is, but power factor has to do with how the phases are loaded right? I think I watched an ElectroBoom video on that. Or maybe Practical Engineering.


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## Dionysus (Mar 17, 2020)

Power Factor has to do with the difference between Resistive, Capacitive and Inductive loads. This effects the waveform and the lag on both each phase and all together. 
Between .90 and 1 are great. The further from 1 the more out of sync the phases are with what would be expected. When Power Factor is consistent its not a problem as well, but large instantaneous swings can cause brownouts (and other problems). The lower the power factor also the more you will be billed for your electricity.


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## MNicolai (Mar 17, 2020)

StradivariusBone said:


> They claimed it was a flow sensor switch that was faulty and they replaced that part, but I'm given to wonder if they were unsure of the definition of current.



Happened to see this thread while on the phone with my director, a mechanical engineer who works on CEP projects regularly. "Sound like they didn't account for inrush. A flow sensor switch wouldn't do anything like that."

The 2 numbers for LRA have to do with the starter. That nameplate looks like it's from Carrier, so in their specs it usually shows up at LRA Star, LRA Delta. For everyone else, LRA "Star" means "Wye". The motor starts up in a wye configuration, at about 1/3 of the LRA in a delta configuration, and then one the motor is almost up to speed it transitions over to the delta configuration. This is known as "Wye Start, Delta Run", and reduces the amount of inrush you encounter.

Trane's documentation is a little better, so here's a snippet from their guides.




Ultimately you will likely need an electrical engineer to investigate. It's probably cheapest (_free_) if you can get the electrical engineer who did the upgrade involved. Failing that, you will have to go third party.


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## Ben Stiegler (Mar 17, 2020)

Dionysus said:


> Power Factor has to do with the difference between Resistive, Capacitive and Inductive loads. This effects the waveform and the lag on both each phase and all together.
> Between .90 and 1 are great. The further from 1 the more out of sync the phases are with what would be expected. When Power Factor is consistent its not a problem as well, but large instantaneous swings can cause brownouts (and other problems). The lower the power factor also the more you will be billed for your electricity.


can you explain the billing impact, pleae?


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## BillConnerFASTC (Mar 17, 2020)

MNicolai said:


> Ultimately you will likely need an electrical engineer to investigate.



Yeah - what a good idea.


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## tjrobb (Mar 17, 2020)

Most likely, undersized conductors. Loose lugs are possible, as is a bad capacitor. You'll need an EE most likely. Or, maybe, both circuits are starting at a cooling call instead of being staged. There are other, much strange, options but those are freak occurrences. 

LRA only happens if the rotor stalls. 3-phase motors are self-starting so the breaker doesn't see that current unless something goes sideways. Which is what the breaker is for anyway.


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## MNicolai (Mar 17, 2020)

Few questions:

Are the brownouts _always_ independent of the chiller? If not, then it could be a utility supply problem.

Typically you can request the utility to come out and do a power quality analysis and they will provide the results to you.

Who is your utility? In talking with my colleague, most of our CEP electrical issues come from co-ops. They may have an underlying problem in their distribution that is being exacerbated by the load from the chiller.

For that matter, is your other building without issues on a different utility or a fundamentally different part of the power grid in your area?


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## StradivariusBone (Mar 17, 2020)

So far as I know it's only when the compressor motor starts up. We already had the utility meter their side and they said nothing is wrong. 

Here's the video I was thinking of that did some explanation of power factor-


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## StradivariusBone (Mar 17, 2020)

MNicolai said:


> Who is your utility? In talking with my colleague, most of our CEP electrical issues come from co-ops. They may have an underlying problem in their distribution that is being exacerbated by the load from the chiller.
> 
> For that matter, is your other building without issues on a different utility or a fundamentally different part of the power grid in your area?



Sorry missed the last two-

FPL is the utility and the other building is a 30 minute drive away and on a barrier island. Very isolated from us.


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## avkid (Mar 17, 2020)

This sounds so much like undersized feeder.
The utility has no problem on their side and EC will never admit it.
You need to get a EE firm with a logging power quality analysis system.


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## StradivariusBone (Mar 18, 2020)

So when you say undersized feeder, are you talking about the cabling from the panel to the chiller, the cable from the outside transformer to the main panel, or the cable from the pole to the outside transformer? The county did put a logging Fluke meter at the main disconnect for about 2 weeks and noted the voltage drops. They also metered our sister building with the same setup. FPL metered at the outside transformer as well and reported no issue. 

I'm friends with the head electrician and he is determined to help solve it, but it's been a back burner issue.


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## avkid (Mar 18, 2020)

It could be at any of those points, first 2 are most likely.


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## SteveB (Mar 19, 2020)

My first thought was feeder undersized. This was due to its a new chiller, possibly requiring a different feeder capacity then previous, did the engineer/architect do the math and require a new feed capacity ?, or try to save some money and go with existing.

My building had to redo the load on a linked section between 2 buildings, one of which was getting replaced. They specified a new 600A panel to be added to the remaining building, I reminded them that the remaining building had undersized feeders and should get looked at. That service entrance had been fed with about 2400 amp capacity on a panel stated at 3000 and they were now adding 600. Oops.... they replaced the feeders.


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## BillConnerFASTC (Mar 19, 2020)

Somehow I naturally assume a new- replacement - chiller should be more efficient than the old one and not require as much power - so seemed odd. 

Maybe instead of fixing feed you can renovate lighting to an all LED system, and reduce load substantially.


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## MNicolai (Mar 19, 2020)

BillConnerFASTC said:


> Somehow I naturally assume a new- replacement - chiller should be more efficient than the old one and not require as much power - so seemed odd.
> 
> Maybe instead of fixing feed you can renovate lighting to an all LED system, and reduce load substantially.



It's common for additions to the buildings or new buildings added on campus to get tagged onto the CHW loop so the upgrade may have added more capacity. If this is a county facility, there's actually a greater chance of this because they might be selling excess CHW to other properties nearby or leveraging this system to support other county facilities down the road. We also see a number of groups here in FL who do ice storage. They run the chiller system all night to make ice at off-peak hours, and then during peak hours turn the chillers off or run at a reduced load and just circulate water over the stored ice until mid/late afternoon. That way most of their HVAC loads are running while they get discounted rates from the utility.

Really hard to guess what the circumstances and former/new conditions are without looking at drawings though.


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## StradivariusBone (Mar 20, 2020)

That's an interesting observation, Mike. The original building was constructed in 1995, complete with it's own chiller plant. The main school campus is handled by two chiller units with several ice storage units. I'm guessing the thought was since the auditorium usage would center around non-peak hours for the main chiller plant, it would make sense to have it on its own system since the main chiller switches over to make ice for the night around 8 or 9pm. 

In or around 2007, they made an addition of a band room and ancillary offices and practice rooms to the back of the auditorium, but also added that facility to the chilled water loop of the auditorium plant. This was still the aging chiller from 1995. As far as I know, the band room addition is fed by the same exterior transformer and is not shared on our main distribution panel in the auditorium. At least there's no disconnect labeled band room in our mech rooms anyway. The interesting thing is the lights dim over there as well when the chiller compressor starts. 

So maybe 2016 or 2017 we finally made the cut to replace the old chiller with the upgraded one. No ice plant, but just a regular chilled water on demand setup, still feeding the band room. It is then theoretically possible that they went with a chiller with greater capacity, knowing that the original one might not have had that built in since the addition was not done until almost a decade after the original construction? That's speculation. Going from what you all have been saying about the feeder, I'm given to wonder if this is not an issue in the underground conduit? We have had a number of water intrusion issues over the years as well as lightning damage frying data lines in the underground runs. A faulty conductor under the slab seems like a potential issue here. In any event, this is all good food for thought. I'm going to submit another work order on Monday and get in touch with my county electrician friend. I'm hoping he's looking for rabbits to chase as well right now. I'll keep the thread updated as I find out more!


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## FMEng (Mar 20, 2020)

I agree that this needs an EE to investigate. It might be a good idea to go to a firm that has mechanical engineers in house, too. Quite often, both work together.


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## BillConnerFASTC (Mar 20, 2020)

FMEng said:


> I agree that this needs an EE to investigate. It might be a good idea to go to a firm that has mechanical engineers in house, too. Quite often, both work together.


Oh yeah, good idea.


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## StradivariusBone (Mar 20, 2020)

I'll mention the Electrical Engineer, lol. I'm at the mercy of people who don't like spending money of course and can't simply call 1-800-Engineer and press 4 for Electrical  I think given the context that the power factor could be increasing energy costs and the damage that may be occurring to equipment, I might be able to make a decent case that further study is warranted.


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## tjrobb (Mar 20, 2020)

Yeah, water is possible. I have a story of a receptacle circuit that the phase wire was completely corroded through, continuity was only provided by the water in the conduit (which is how they had 97V).


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## Jay Ashworth (Mar 22, 2020)

My snappy answer is that if you have a 460/480VAC internal distribution system, you should have a house sparky, even if he's not full time.

But yet, what everyone else said; sounds like your new chiller has a starting amp draw enough higher than the old one that it pulls the entire facility voltage below nominal. And that is likeliest to be the street drop, not internal, cause if it was just the wires *to the chiller*, it wouldn't affect the others as much. It would probably still dip them some, but...

What I'm wondering is why the power quality meter didn't show that. Did they give you a stripchart?


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## Dionysus (Mar 22, 2020)

Ben Stiegler said:


> can you explain the billing impact, pleae?



I THOUGHT I had replied to this... Here is a link to a power provider website talking about itt...







Power factor and your bill





app.bchydro.com


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## MNicolai (Mar 22, 2020)

I did some investigation and we're familiar with this project. We were the third-party Cx agent which basically means once the system is installed one of our mechanical engineers confirms it has been brought online and programmed correctly. I've reached out to the engineers in my Cocoa office who were involved in this project for more info.


StradivariusBone said:


> I'm at the mercy of people who don't like spending money of course and can't simply call 1-800-Engineer and press 4 for Electrical



Actually, the district kind of does have this in place. There is a master continuing services agreement for MEP Engineering services, which basically means there's an expedited process in place for procuring engineering services, particularly for these kinds of smaller projects. My firm as well as a couple others are part of that agreement. I don't know how far your maintenance staff have escalated this up the food chain but if you get approval from someone in your facilities dept there's actually very little red tape involved. Waiting to hear back from my team in Cocoa who they normally work with from the district that they could flag this issue to.


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## StradivariusBone (Mar 23, 2020)

Thanks for that, Mike! I spoke with my people here this morning so we'll see what comes of it.


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## Jay Ashworth (Dec 22, 2020)

Spammer reported.

So... update?


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## StradivariusBone (Dec 22, 2020)

Not much to update unfortunately. I contacted a few friends I have up at facility plant, but right now they're still just trying to finish the HVAC automation upgrades (which don't work great) among other things that were spurred by the flurry of legislation post-Parkland (e.g. lots of security cameras, gates, etc.). It's kind of a mess overall, brownouts are still happening, but it hasn't been as noticeable lately because we just haven't had as many events as we usually do. 


kopwqqaa said:


> The LED display controller from Europe



If the LED display is in Europe though, how does that help us here in America?


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## FMEng (Dec 24, 2020)

It shouldn't be that hard to track down. Measure where voltage sags and where it doesn't. If the voltage does not sag at the transformer, and it does at the lugs of the main breaker, then there is either a loose connection, or an undersized feeder between the two points. If it's good at the main lugs, and bad on branch breakers, then look hard at the the main breaker itself and the busses. 

It doesn't take fancy test equipment. Some moderately priced voltmeters have fast responding, min/max hold, and should be able to measure the problem. A favorite of mine is the Fluke 87V. I used one to find similar problems. Get the right test leads to get solid, safe connections for long periods of time.

An infrared thermometer or IR camera can also help. Voltage drop on a connection means resistance and resulting heat. Discoloration and damaged insulation are also signs of trouble.


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## Lyle Williams (Dec 30, 2020)

As many have said, this is one for an experienced electrician rather than the internet.

But it would be interesting to see if the brownouts were on all phases. eg Undervoltage on one phase at the same time as overvoltage on another would imply a different kind of fault.


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## Jay Ashworth (Aug 7, 2021)

Fun side trip: I like to describe our campus theatre/building as having "nuclear-powered air conditioning", a phrase I stole, from, probably, _The Hunt For Red October._ A little research this week, it turns out the central chiller plant that cools the 9 buildings on this campus, plus a bunch of other commercial customers, is a *3400-ton* Trane plant.


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## TimMc (Aug 7, 2021)

Jay Ashworth said:


> Fun side trip: I like to describe our campus theatre/building as having "nuclear-powered air conditioning", a phrase I stole, from, probably, _The Hunt For Red October._ A little research this week, it turns out the central chiller plant that cools the 9 buildings on this campus, plus a bunch of other commercial customers, is a *3400-ton* Trane plant.


That's a whole lot of ice...


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## JonCarter (Aug 7, 2021)

I'm with Bill Connor's comment way back last year. Get an EE involved, do some current load calcs, monitor the hardware, watch the voltages and current draws at critical points in the system and put together an info package of what's happening when and where. That's the only way you'll know if the problem is yours or the POCO's.


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