Category: HVAC

Just cool it, FUCKWEASEL.

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I should not have to be repeatedly giving attention to the innards of HVAC chillers, but here I am because everything fucking sucks significant amounts of elephant pisstube.

It’s hot and the air is barbecued toxic shit outside so I’m not going to bother taking exterior pictures of the chiller in question, but here’s its story.

It started out life as a perfectly fine York unit with four Copeland Scroll compressors, four inverted A-frame coils, and six axial fans on top to suck the hot air out after it’s moved across them.

Then someone decided, hey, Turbocor compressors are pretty boss, let’s swap it over to one of those. Okay.

Hey, let’s also try to give it variable speed fans, based on…. uhhhhhhh…

Whatever This Shit Is. Uhhhhhhhhhhhhhh—-

Now let’s put a water misted cooling pad system on the air inlets and make it look like something that was field expediently whacked together in the back of a barn OH FUCK GO BACK NO

Here’s the end result. At some point someone cleared out the electrical cabinet of everything but the main disconnect and rebuilt it with……a mountain of weird shit. This is the left side where the contactors for the compressors and fans would have normally been. I don’t know what the deal is with that thing that looks like a transformer, it’s just an 3 phase “reactor” – an inductor.


Not particularly visible at the bottom: a set of current transformers on the Turbocor’s power wires that set off the water misters when it begins to spool up, and a pair of fans rigged in the bottom to keep the VFDs cool…ish. They’re powered through the barrier strip on the far right.


In the compartment which would have formerly held the logic board that controlled the old setup, the two relays to the left of the Turbocor interface board turn on the cooling fans at the bottom, and…. well, I have no idea what the second one does. I couldn’t trace this out and there’s no documentation left with it. In short, I have already run out of fucks to give.


Um, what the fuck happened to R12? Again, lack of fucks to give, the thing still runs ok. Not sure what the LEDs are indicating but when D5 through D8 flicker periodically.

I’m fairly sure the Turbocor must actually be capable of commanding variable frequency fan drives to cool the condenser, but oops, someone put that weirdass blue pressurestat in place instead. That thing is fucking weird. It sits there and does nothing until the pressure is like 4 PSI below setpoint, then the command voltage it sends just abruptly leaps up from 0 to 10v, making the variable frequency drives… not so variable…


Anyway the reason I had to mess with this thing is one of the drives lost a 24VDC cooling fan. Our HVAC contractor looked into ordering a new fan and found out that a replacement would be at least SIX MONTHS OUT. The original, an NMB 3110KL-05W-B50 (80mm, ball bearing, 24v, 0.15A) appears to be Fuck You NLA. In fact, almost all 80mm 24VDC fans appear to be unavailable. I begrudgingly, out of desperation, dug into my own supplies and grabbed a little switching buck converter that’d take the 24VDC from the VFD and step it down to 12V to run a fan that actually IS available and extremely common.

Now the dumb thing spits out cold water again and I’m not quite as mad. I’m still going to swear at the fucking bellend thing though.

Steamed.

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I’m a little annoyed with having to deal with air conditioning nonsense right before a weekend I don’t get any time off from work because we’re so understaffed. We have an HVAC contractor who is supposed to deal with this but they’re completely clueless when it comes to large systems. They have one guy in the company who understands the Metasys controls and somehow I know more about them than he does.

🎵 Look at this graph 🎵

The last big issue I had was with this one air handler / fan coil unit on the roof that cools both control rooms and our newsroom via a Medusa head of VAV boxes. First it had been shutting down, it turned out the variable frequency drive was on an HVDC overvolt fault and didn’t automatically restart. I programmed it to do so. The service company looked at me like I was speaking Martian COBOL when I explained this to them.

I also asked them if the belts to that blower it runs were too loose. They don’t know. They couldn’t advise me on this and didn’t know how to check. I’m not touching this with a social distancing pole.

Today it was acting up in a different way and I found Metasys reporting the cold duct pressure was 0.1″ water column. When I opened the blower access door on this totally turdly air handler, it jumped up to 0.7″ and the VAV boxes actually started, you know…… working. Opening the door took an unreasonable amount of force and only after I opened the door, the system started calling for less than 100% blower speed. Hmmmm.

Gee I wonder why there’d be that much airflow restriction on the inlet? Let’s see, shall we?

Gaaaaaaaaaahhhhhhh

These coils were supposedly cleaned! Uh…. No.

On a side note, the fact that our chiller’s variable output capability is simply not used and instead it was just saddled with this foam rubber covered Chipotle burrito tank and set to on/off cycle makes me wonder

the spaghettinator

Here’s to hoping this hot weekend goes uneventfully.

Treat the variable frequency drive with kindness

kg4cyx2 Comments

Variable frequency AC drive controllers are all sorts of amazing. They rectify AC power to DC then give you 3 phase AC at the desired frequency to let you run the motor at the desired speed, anywhere from just a few RPM up to full tilt. They can also, if misconfigured, drive you up the wall at 60 cycles per second.

I’ll save you the pain of having to watch me scream about Johnson Controls Metasys, here’s the data showing that this one air handler is not happy. This graph is showing its air output temperature. This morning I came in to find half the facility nearing meltdown and decided to see if I could do anything about it.

There’s the drive for that unit’s blower. I found it shut off on a DC bus overvolt fault. The automatic fault restart was not enabled, so it just sat there.

I restarted it and watched it ramp up to full speed…. fearsomely. After it’d let the place cool down a while I revisited the settings. This Yaskawa controller actually has pretty good documentation and a setup routine designed to aid in quick deployment (I CANNOT say that for all the controllers I’ve come across in the wild). Right away I noticed the amperage and wattage limits set in the controller did not match the motor, which did not appear to be original to the unit.

Yeah uh I’m gonna have to recommend you not do that. I filled out the proper values in there, turned on fault restart, and ran the auto tune, which sounds like angry crickets on this unit.

Aside from the drain pan looking suitably foul, I’d say it’s happy again.

I dunno, I realize that variable frequency drives are probably a bit of crazy black magic to a lot of HVAC people, but pleeeeeeeeeaasseeeee make sure you have the thing configured right for whatever motor you’ve wired to it! It does make a lot of difference!

Oh, and the Johnson Controls corporation is a bellended bagbiting cockwomble. There i said it ok

assfoam

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I can’t even. The wall shaker A/C was iced over when I got to the site and a mix of frost and mildew was coating the front grill. I set it to fan only and let it sit there and think about what it had done while I went up to the Ace Hardware and got some coil cleaner. Here it is initially, after most of the ice melted.

slinger ring fan description
that sloshy noise making thing

Then I shut it and the small backup unit above it off, applied the coil cleaner to the evaporators and condensers of both, waited ten minutes, hosed them down thoroughly with my pump sprayer bottle full of water, and turned them back on.

Seems I forgot about four important things:

A) both sets of condenser coils and evaporator coils had a massive amount of oily smoke residue from the wildfires and the transmitter fire on them;
B) when you use this cleaner, it saponifies oily (non polar) residues into a soap that will bind to water molecules for easy removal, using a nice amount of sodium metasilicate as an alkali reagent;
C) the drain pans on most modern wall/window A/C units RETAIN some water and use a slinger ring on the condenser fan to throw it on the coils;
D) this action will cause a lot of air to be entrained in whatever condensate water runs into the pan….

I heard the fan speed slow on both units after they’d been running a while and looked out to find this great outpouring of suds that smelled strongly like ass. Assfoam. ew. ASSFOAM!!! Get it out of here! Ugh.

While this was all happening, one of the neighbors came walking up, noticed my Golden State Pinball Festival shirt, and asked me how a Death Save is supposed to work. I admitted to him that while I know how it works, I’ve never been successful in coming away with anything but a bunch of tilt warnings and sore hands. (It’s banned in tournament play as it can cause player injury and damage to the pinball machine. Don’t do it on someone else’s game, or on yours if you don’t like the idea of damaging the legs and cabinet, mmkay?) Video of a successful Death Save below.


Here’s the Death Save in action. It’s fairly brutal. If the ball right drains on me I just let it go, but I’ll certainly shake the game around a bit to try to bounce the ball out of the outlane area before it decides to sink in there!

Here’s the more dangerous (to the player!) left-handed brother, the Bang Back… it doesn’t appear to be as likely to damage the game, but as they mention in the video, you can break your wrist trying to save the ball!

Of all games they could have chosen to demonstrate this on— they chose the mighty, heavy, widebody Twilight Zone!!! Hardcore.

Here’s another video where several different types of nudges are shown as a game is being played and explained, including forward nudges to bounce the ball off of the rubber parts near the outlane to get it out of harm’s way, and sideways nudges for slap saves of balls headed straight down the middle [SDTM].

 

More old Honeywell thermostat fun

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Previously, and thermionic valve based.

One of the sites I work on has two old Honeywell thermostats on the wall that are like nothing I’ve seen elsewhere and it kinda intrigues me. These have a small bellows inside and act upon temperature changing the pressure of gas sealed within it. I wonder if they have to thus be calibrated for altitude?

I’d guess circa 1960s-1970s based on the date of other gear at this site.

First, the cooling thermostat – it’s a pretty straightforward mercury switch two-stage type. BIG mercury switches, though – much bigger than Honeywell would have put in their standard home HVAC controls…

The setpoint is adjusted using the hex screw on the side.

Next, the heating thermostat, which really had me scratching my head:


The contact arrangement is curious. This thermostat does not appear to just switch on and off, rather, its output appears to be a variable wirewound resistor! Said resistor is also mounted far from the bellows, so it’s definitely not just an anticipator resistor. This makes me wonder if it was actually more of a remote sensor to something fancier—? Apparently it’s a “proportional control” and I wonder what the original heating system up there was. The original HVAC system has been mostly removed and replaced with a boringly modern one.

 

Aww shim

kg4cyx4 Comments

So that buzzing sound my 2014 Forester’s a/c compressor made since last year? Yeah it wasn’t supposed to do that.

I checked the clutch gap today after suffering mild heat exhaustion in 102 degree weather with the A/C blowing warm… .82 millimeter… Factory specs say 0.1-0.6mm.

Thus it was time to subtract a shim from the shaft.

And then my workday jumped to like 10 hours and crap so what follows:

There’s actually nothing to stop this from turning so I just grabbed it with my hand and used the wrench on the center bolt because I’m some scary beast

The compressor drive plate before cleaning

Pulley side after removing all three shims and before cleaning

I saw it recommended to torque the center to 10 foot pounds which worked fine with my bare hands, once again….

Now it seems I just have cold air constantly and no buzzing noise (was that it slipping??)

Update and data for the purposes of making this a little more indexing friendly: This compressor is a Valeo DKV-10Z
Subaru TSB number 10-84-16R indicates there’s a known issue with the electromagnet that contributes to this and that the official fix is to replace the compressor. However, the issue is actually entirely confined to the clutch itself and I’ve seen a clutch replacement kit available for about $90. If your vehicle is under warranty, go to the dealer for service. If not, the $90 kit should do, and you don’t have to evac/recharge the system. Looks to me like the only interesting tool you might need would be a snap ring plier and maaaaybe a puller and the spanner wrench for the rotor (since not everyone can just grab the front plate of the clutch like I can!)

bUt wE’re ProFEssIonAls nOt YOu

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Local HVAC service contractor: “Oh, yeah, we know what’s going on, your condenser coils are just dirty.”

Technician shows up and sprays the coils then promptly leaves.

Air conditioning continues to not work. Vital equipment starts to warn of impending thermal shutdown.

I go out and take a look at the condenser for literally four seconds.

ICE ICE BABY

how. HOW DID YOU MISS THIS???!!! Were you too busy trying to capture our ample local supply of rock and bug type Pokemon or something and never bothered to look at ANYTHING???

Pissing the night away—-

This is as obvious as the nose on your face. Damn thing’s iced over. That’s why we had no cooling. I set the unit to fan only and the amount of water that came flying out the condensate pipe was stunning.

Also, when the other tech came out to actually check everything, I got horribly, seriously confused by his gauges.

 

25 Cent Life Hack: Stop Ceiling Fan Wobble

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Got a wobbling fan?

Stop the fan and tip it with your hand. Don’t hit the ceiling.

Move it slowly and watch as it rocks and settles down. The high side needs a balance weight.

As suggested by the title, I stuck a quarter up there with a double sided tape pad from the junk drawer.

Adjust / repeat as necessary.

* may also work with a penny, dime, two quarters— your mileage may vary. Probably won’t work on “hugger” style low profile fans as easily as you can’t tilt them – just try the weight on each blade until you see the best improvement then fine tune by moving it in and out on the blade.

The problem with air conditioned cabinets in Florida

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These boxes are everywhere around here because certain equipment that needs to be stationed outdoors isn’t happy with the 96 degree F summer outdoor temperatures. They’re an outdoor weather resistant enclosure, with an air conditioning unit attached through one side.

Chill.

Air conditioning units have two functions. They reduce temperature and humidity. The amount of humidity they remove is proportional to the amount of time the unit is in cooling mode.

This cabinet is very well insulated and has a very low heat load… Watch this Nautel loooooaf along…

Standing next to it, I saw that little a/c pack start maybe once every 10 minutes, for about a minute at a time.

 

Brace yourself, the results ain’t pretty.

 

Fungus Among us?!

 

This curious white fungus is attacking rubber parts…

 

 

Various points of moisture or fungus damage…

 

And as an added bonus, open this cabinet on a hot humid day and you’ll be treated to the horrific sight of the equipment becoming soaking wet while still actively running…

 

Insects have been attracted to the cabinet by moisture… This is after a big vacuuming, the junk stuck to the cabinet ain’t gonna yield to that alone…

 

So what’s the solution? I can think of a couple things.

A) do not oversize the air conditioner. This is tricky as heat load is unpredictable and failure to remove enough heat would quickly cause a shutdown or equipment damage.

B) place constantly on LED lights inside to inhibit this mold/fungus growth.

C) use humidity controls on the a/c or a dehumidifier if possible. Not sure if you could easily fit a humidistat to this unit as it’s got its own integrated microprocessor control (hidden behind that piece of filter)… But who knows.

 

 

Fnord Motor Company

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Last weekend, when I was making the drive to Derp Island, deep in the Florida Keys, it was pretty hot but stormy out and I was driving down there with the A/C on in the car set to use outside air, since the air down there is not 97% diesel spooge like it is up on the mainland. As I was going down the road I noticed the A/C started getting slightly warmer, then the airflow abruptly dropped as if the blower was burning out or the system had sucked in rainwater and soaked the cabin air filter. (I’ve had both happen on that car. We wear out A/C system blowers here in South Florida like mad.)

Then smoke blew out of the vents……!!

I pulled off at a gas station, stopped, and was looking around trying to figure out what Let The Smoke Out, unsuccessfully. Then I started the car again and… maddeningly… everything worked fine, although I had the reduced airflow problem every now and then afterwards.

Last night, I was driving down what I like to call Miami-Dade County’s emergency exit (I’m not telling, otherwise EVERYONE will try taking it!). The road was empty and as it started raining, I hit the vent button again. The airflow faded away again after a burst of fog came out of the vents, then the airflow cut back. I suspected a coil freeze. Sure enough.. I turned off the compressor and cold wet air began to gradually blast out of the vents.

For sake of illustration, a typical, severely frozen over A/C coil. Watch out – this often leads to flooding.

Later, with the A/C back on again, the airflow started to fade away… then the engine misfired(??) and shut down impolitely. I shifted into neutral and coasted into a well lit parking lot to investigate. I found three blown fuses.

Now I was thoroughly baffled, why did things SHORT OUT? I pulled the glove compartment off to look at the area where the cabin air filter is, and found that a wiring harness runs along the plastic air duct. Just almost out of view in the center console area, that ran between the duct and a razor sharp edge on the dash frame.

The plastic duct had swollen up from the ice buildup and pinched the harness, cutting into some wires.

Sorry, no pictures as the clearances were insufficient to get my phone into the space. I was working with a flashlight and a dental mirror!

I fixed the issue for the time being with electrical tape and cable ties to hold the harness out of the area where it’d gotten pinched, and cut up a plastic bottle to serve as a protective sleeve.

 

Lessons gathered from this:

A. fnord!*

B. Never trust lazy automotive engineering.

C. Don’t let your A/C refrigerant get low.

 

 

* Fnord? What is fnord?

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