Fnord Motor Company

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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SLIME.

This has been a bad week when it comes to things full of water.

First, early in the week, I was walking down a corridor at work when a big fat raindrop got me right in the eye. I jumped a little and this caused my shoes to hydroplane on the wet floor.

Upon further inspection, it was coming from a large overhead AC unit. The drain was clogged. I used a wet vac to clean up and finally to forcibly blow the snot rocket out of the line.

Then the toilet tank in my apartment spontaneously cracked open and tried to start a flood. It started with a bang, ended with the somber howl of a Home Depot cheapie wet vac.

Then I was informed that water was pouring thunderously down the side of the building while I was at work. The fault was one we’re not unfamiliar with.

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The thing in the foreground is a large ballcock like that which would fill your toilet. Something was wrong inside it and it wouldn’t stop gushing so I reduced the water flow to it from a roaring geyser to a smaller, “someone left the sink on” flow and went back inside.

Later, the 11 pm news had just ended when I heard a very odd noise in the building and started trying to track it down. My first thought was maybe the water level in the tower had fallen, but there was still water pouring off the roof, so that couldn’t be it. It seemed like a lot, actually. And that’s when the temperature alarms started going off….

I switched on a backup ac for our most critical server room and took a look at the pool on the roof. The first thing I noticed was it was overflowing but I didn’t hear much water flow in it and the fan wasn’t on. I peeked inside again and realized that this time I couldn’t see the sieve at the bottom anymore. I opened the filler valve back up full blast so I could also use the garden hose up there.

Uh oh. I located a stick and started poking around. I found the sieve had become totally occluded with a mat of algae.

Scrape
Schlorp
Bloop
Slurp
Squirt, squirt
Chatter
Bang
Gurgle

The next thing I knew, I was looking at the sieve…. but no water. It was running down there as fast as it filled the basin, but now it was also raining down through the fill like it should, albeit slowly.

It continued to do this a while as the entire system refilled.

My only thought is that the entire system had basically started sucking air back through the overflow pipe adjacent to the main drain/return as the sieve plugged, and the pumps had cheerfully returned all the water back to the overflowing tower until there was just about nothing left but the small amount needed to churn back and forth in the pumps and make awful sounds.

Once refilled, I found all the AC units cooling once again, and the awful sounds absent.

But why the slime? There’s a system to prevent that….

Oh

Heck

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The barrel. What’s in it?

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Nothing. In fact there’s algae in the barrel itself…

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Algae and calcium build up all over

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A pump that sounds fouled

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And a cool looking skyline

So at least there’s that

Also, for no good reason one of the air handlers seems to have experienced an accidental thrust reverser deployment and yacked all over the place

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And it’s still pissing itself. At least everything is staying cool…

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Good night from beautiful Broadcast Key, Miami, Florida.

Industrial elegance

This unit is an old Honeywell thermostat. Wait for it….

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Waaaait for it

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TUBES.

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The fan contactor:

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Breaker panel. These Pushmatic breakers are known for being a little flaky. It’s all decommissioned.

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Why black and green? The National Electrical Code says green is ground. Nothing else. Ground. I dunno. This is outside of my pay grade. 😉

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Nooooooooooooooooooooope! That’s the worst possible error!!

Fair Weather Air Conditioning

So I figured if I’m gonna rant about stupid construction, I might as well also mention how not to run a facility air conditioning system.

First, the chillers.

A chiller is essentially a giant version of what’s inside a drinking fountain. It sucks heat out of water and kicks it into the air (usually, but not always… I’ve seen one that heated a swimming pool!)

Or in this case, it does fuckall nothing.

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That’s the unit, installed outdoors. The long insulated weinerschnitzel on the bottom is the heat exchanger that circulates water around the evaporator coil of the sealed refrigerant system. This one uses, or used, R-134A. I wonder if it’s all still in there? The two devices on top are a pair of compressors.

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Or, maybe, “were”.

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Well, it works

I’d always wondered upon seeing airflow readings in cfm displayed on a room thermostat on a VAV (variable air volume) system as to where that data came from.

Well, here’s my answer. Inside a VAV box displaced during construction, I found this peeking out.

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The top tube with holes in it faces the incoming airflow and is thus a  Pitot tube. The dome in the middle covers and shields the end of the other hose which is the static pressure tube. A differential pressure sensor in the control unit that measures the difference in pressure can thus derive the speed of airflow, and multiplying that by the area of the duct opening gives you the volume. Simple as that.

This is actually kinda simple as vav terminals go. Some are more intricate and contain blowers. All this one has to control the airflow is a butterfly valve damper.

VAV is one of those things that looks good on paper but in practice leads to weird comfort issues. Thankfully our facility averts those all by simply never getting cool enough, so the airflow just runs full tilt all the time. Problem solved, now get me a curry chicken empanada.

Another day, another dead air moment

About a year ago I installed a little Dayton thermostat in the interlock line to Mr. Harris, set to open at 110 degrees F. Last night at about 1:39 am, it tripped while I was sleeping. I couldn’t figure out looking at the telemetry data half asleep what was up, and just decided to go check it out.

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The fault was a very common and dumb one, a seized a/c condenser fan motor. However what I found down there was…. Amazing.

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Old Rheem… Just about as cost engineered as it gets without going all the way down to Goodman / Janitrol (Junktrol).

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Uh oh!! This is either “Game Over” or “just wait a few minutes for the reset”. Thankfully it was the latter. The thermal breaker reset after I started hosing the crap out of the evap coil.

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All Rheem units of this vintage and design have the wires to the fan and compressor running through barely rounded off holes in the sheet metal electrical box. Rubbing was visible on some so I field modified a bit of nonmetallic conduit into a pair of protective sleeves.

But then well, uhhhh…..

Here’s where the fan motor run capacitor is supposed to go.

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Here’s where I found it.

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What in the ever living fuck???!!!

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After removing it from that cardboard and self-amalgamating tar tape coccoon, I found it tested good. Weird!! It was even exactly the right shape and size to mount in the flange seen above, WHY was it like this?!

Also, we’re not going to talk about the fact that a single phase fan motor was inexplicably plopped on a 3 phase unit? (Every Rheem I’ve seen is like this.)

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What a weird mess. Maybe I should have been an HVAC tech. Or maybe not… I’d probably get excessively mad at someone first day on the job and slice them to death with a sharpened condenser fan blade hammered into a shuriken of death.

Wouldn’t that just be perfectly METAL? \m/

 

EDIT: The underlying fault was that the condenser fan bearing has a bad spot. If it stopped in a certain place, the motor would not have enough torque to start turning the fan again. This caused it to pretty much become the worst form of roulette wheel. Our A/C guy brought out a replacement motor but we goofed – I read “208” in giant numbers on the side and assumed that meant it was a 208/240 volt motor… he put in said motor and it went AAAAAAAAAAAAAAAAAAAAAAAAZZZZZZZZZZ*POP* and let the genie out after about 20 seconds… ON 480 VOLTS! Oopsie noodles. 🙁

Gonna try again tomorrow.

Also before anyone comments on electrical safety hazards with my rings and stuff — this unit was disconnected at TWO different points and verified to be 100% voltage-free before I went at it at all. There was just no way anything nasty could happen. I took a nice solid hit of 480 on Halloween night in 2000* and it was one of the most painful things I’ve ever experienced. It is an experience I do not want to repeat. Thus, I would not even get near the unit until I’d opened both disconnects in series with it. NOOOOOOPE!!!

One of the weird side effects of this was that it caused nerve damage. The human nervous system has a remarkable ability to rewire and retrain itself, unfortunately, it didn’t exactly follow the blueprints quite right and the nerves in my hands actually start misfiring very bad phantom sensations if I *don’t* at least have something sitting against my wrists. wpid-IMG_20120114_181019.jpgYou can see my old workaround for this here, and that actually WAS free of any electrical safety hazards. Some of them even glowed in the dark.

The peculiar advantage to this? I don’t need a logic probe to figure out if a pin on a chip is being pulled up to 5v… I just have to touch my thumb to ground and hold a nail or other small conductive object between two other fingers and I can feel it. digitalRead(); this, baby.

* I make it sound more interesting than it actually was – it happened due to touching parts of two adjacent yet not electrically bonded escalators that had just been freshly miswired and put into service. It was just a dumb coincidence it happened on Halloween.