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iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

We didn't have a HVAC thread so here goes.

I work primarily on large commercial and industrial systems, so the majority of my contributions to this thread are going to be that.

This thread may or may not me an excuse for me to post pictures of all the cool stuff I get to work on, but feel free to contribute or ask questions about your system.

Just a few primers:

* Never disable any safety devices on your HVAC system. They are there for a reason and you can burn your house down, die, be seriously injured, or all of the above if you disable them and something goes wrong.

* Refrigerant sprayed/leaked onto your skin will give you frostbite and is made up of hazardous chemicals. Do not mess with the refrigerant side of systems unless you know what you are doing.

* Electricity is dangerous. Seriously. It will kill you, and it will hurt the whole time you are dying. Again, if you don't know how to safely work with it, DON'T. Always turn off the power to whatever you are working on. Buy a quality meter and learn how to use it BEFORE you touch live electrical.

* Gas leaks will blow your house up, burn it down, or burn you. Shut the gas off before you take any pipes apart and make sure the space is well ventilated when opening up any lines containing fuel gas.

* Youtube will not teach you everything. Just because you see someone do something in a video doesn't mean it is the right way to do things in your particular case. I am not liable if you break something and it costs you your savings to fix.

This video is a good primer on how A/C systems work. It doesn't teach you everything, but you will learn the basic concepts.
https://www.youtube.com/watch?v=_lFUlA1PZ8U

The systems I work on the most have a capacity 150-600 times larger than a standard unit you would have at your house but they work using the same basic principles. Most of the time they are chillers, which chill water which is then pumped through the building to coils like the evaporator described in the above video. I do work on smaller units, but not as often.

I work in rooms like this a lot:


Sometimes on huge boilers half the size of a city bus:


Other times, it's large fan blades for a cooling tower:


Motor bearings on a 540 horsepower electric motor off a chiller:



Sometimes it's coils so clogged with bird poo poo that the machine won't run due to lack of airflow:


Or just a simple gas valve replacement on my parents' heater:

iForge fucked around with this message at 05:11 on Jan 24, 2016

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iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

Just some pictures of what I am working on right now. It is a teardown/rebuild of a centrifugal compressor 450 ton Trane Centravac chiller. The rating of tons is not weight, but the heat transfer that 450 tons of ice melting can do in 24 hours. Some of these parts are aluminum and weigh 50-100 pounds. Others are steel and weigh upwards of 1200 pounds.














Hung my hat up for the weekend.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Oh cool, and HVAC thread. I guess I can contribute here too!

I work on commercial units, mostly just package and split systems, up to like 50 tons. It's pretty much all the same stuff you have in your house, just on much larger scale.
Through I do refrigeration as well, everything from stand up fridges and freezers, to warehouse sized walk-in freezers and coolers. Oh, and ice machines, can't forget about ice machines!

Our company also does supermarket rack refrigeration, which is some cool mechanical stuff, and a whole shitton of electrical stuff. I'll have to grab some pics next time I'm out.
But, in the meantime, enjoy this picture of a compressor room from Google:


Yeah, I wish the rooms I worked in were that clean and organized.

The basic way of describing this imagine one compressor feeding multiple units. Or in the case of most stores, 3 monster compressors feeding upwards of 10 reach in coolers, 12 walk-ins, and a deli display.
Usually home pretty heavy duty stuff, big 3 phase 50HP motors, Big heavy compressors, and multiple panels completely filled with contractors, wires, and relays for the evap motors/defrost/monitoring system, etc. Plus these things take a shitton of refrigerant to run, upwards of 300lbs. (For reference your home split-system might take like 10lbs.)


So I'll be happy to contribute as best I can, and answer any questions about refrigeration you might have as well.


E. Question for iForge, do you work on any Ammonia systems? Or all just normal refrigerant systems?

ExplodingSims fucked around with this message at 03:05 on Jan 24, 2016

iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

ExplodingSims posted:

Oh cool, and HVAC thread. I guess I can contribute here too!

I work on commercial units, mostly just package and split systems, up to like 50 tons. It's pretty much all the same stuff you have in your house, just on much larger scale.
Through I do refrigeration as well, everything from stand up fridges and freezers, to warehouse sized walk-in freezers and coolers. Oh, and ice machines, can't forget about ice machines!

Our company also does supermarket rack refrigeration, which is some cool mechanical stuff, and a whole shitton of electrical stuff. I'll have to grab some pics next time I'm out.
But, in the meantime, enjoy this picture of a compressor room from Google:


Yeah, I wish the rooms I worked in were that clean and organized.

The basic way of describing this imagine one compressor feeding multiple units. Or in the case of most stores, 3 monster compressors feeding upwards of 10 reach in coolers, 12 walk-ins, and a deli display.
Usually home pretty heavy duty stuff, big 3 phase 50HP motors, Big heavy compressors, and multiple panels completely filled with contractors, wires, and relays for the evap motors/defrost/monitoring system, etc. Plus these things take a shitton of refrigerant to run, upwards of 300lbs. (For reference your home split-system might take like 10lbs.)


So I'll be happy to contribute as best I can, and answer any questions about refrigeration you might have as well.


E. Question for iForge, do you work on any Ammonia systems? Or all just normal refrigerant systems?

I have never worked on an ammonia system and as far as I know, we don't have any customers under contract that have ammonia systems so I won't be touching one any time soon. Glad to see someone else in the trade contributing, I've done very little with commercial refrigeration so feel free to talk about that all you want! I mostly do large tonnage chillers, cooling towers, packages, splits, and the occasional boiler.

literally a fish
Oct 2, 2014

German officer Johannes Bolter peeks out the hatch of his Tiger I heavy tank during a quiet moment before the Battle of Kursk - c:1943 (colorized)


Slippery Tilde

iForge posted:

Just some pictures of what I am working on right now. It is a teardown/rebuild of a centrifugal compressor 450 ton Trane Centravac chiller.
[photos of giant awesome compressor]

Someone bring me a Rolls-Royce Merlin. I found a better supercharger.

E: The Subaru's A/C compressor has started going TAPTAPTAPTAPTAP when it's hot/operating. Is this because it spent a couple of weeks upside down (not being operated), or did it just died?

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




So, that video that iForge posted in the OP is pretty basic intro to AC, so I figured I go a bit more in depth to really get this thread rolling.

I'm gonna try to break this down into simple parts, and we'll go over a basic rundown of the mechanical side, and the electrical side as well.
So, let's get this going:



This is your basic (Straight cool) home AC system, and it can divided into two halves, the low side, which is the side that cools, and the high side, which were the hot gas is.
The high side is mostly contained in you condenser unit, on a split system, and the low side is mostly in the air handler, which is usually in your garage, attic, or maybe stuffed in a closet.
Now every refrigeration and A/C system is made up of the four basic components, which we'll now go over:

1. The compressor, I'm sure you can guess what this does! This compresses the refrigerant, which is in a gas state, and sends it into the condenser. This feeds the refrigerant into the discharge line, which is very hot. Try not to touch it while in operation.

2. The Condenser coils. This is where the hot gas is changed into a warm liquid. Refrigerant travels through the coils, and the condenser fan pulls air across the fins, which removes heat from the refrigerant, allowing it to change states into a liquid. This can cause problems if the fins get dirty and blocked up, but more on that later. This feeds the refrigerant into the liquid line, which takes it to...

3.The Expansion device: This is what starts the cooling process, this is basically a small restriction that forces the refrigerant to flash back into a gas, and get cold. There's a couple different types of expansion devices on there, but on a home AC, you're most likely to find a TXV, Thermostatic Expansion Valve.

This part is made of the valve body, and the superhead. The way this valve works, is that there's a sensing bulb filled with refrigerant connected to the superhead. The sensing bulb is attached to the side of the the suction line, and depending on the temperature of the line, the pressure in the bulb changes, and forces the spring-loaded valve inside to move up or down, allowing more or less refrigerant flow through the valve body.



3a. Now some newer systems, especially higher end ones, may come with a EEV, Electronic Expansion Valve. This basically the same concept as a TXV, except it uses electronic inputs from a sensor to drive a little stepper motor to open or close the valve.

No matter which valve you may have this will pretty much always be located in the air handler, very close to the inlet of the evaporator coils.

4. The Evaporator coil. So now that we have a low pressure, low temperature gas, the cooling can begin. The gas travels through this coil, and the blower motor sucks warm air across the fins, and the refrigerant absorbs the heat from the air, leaving you with nice, cold air in your ducts. Much like the condenser, if this coil gets dirty it can cause some serious problems down the line. Change your filters! Now as a byproduct, the evap will accumulate moisture on it, due to it sucking the moisture out of the warm air, so you'll have a small drain pan under the coil to catch all this. This can and will get clogged up with slime.

And after the gas has passed through the coils, it gets sucked back to the compressor to start the cycle all over again!.

Now that's just a basic overview of the straight cool system, so there may be a few more steps involved if you have a heat pump system.
What's a heat pump? It's a system that can basically reverse itself, so that the evaporator coil acts as a condenser, and the condenser as an evap. How does this happen? Through the magic of the reversing valve!


This guys sits on the end of the discharge line coming off of the compressor, and before the suction line goes into the compressor.
It's basically a U-bend that sits on a track, and there's a solenoid that engages to pull it to one side. Allowing the gas to flow either to the evap, or condenser. When it calls for the heating the hot discharge gas is sent to the evap, and the then it runs the same process as cooling, only in reverse.

Now there are a few other parts on the line as well, so let's knock those out too.

Every refrigeration system needs a dryer on the liquid line. EVERY SYSTEM. This is filled with a desiccant that absorbs moisture out of the refrigerant. Why? Because moisture is the enemy of refrigerant. It will gently caress up your system, by acidifying the refrigerant, and that will lead to compressor destruction. If you open any system for repair, you must always replace the dryer. It should be the last part you put in as well.


Sometimes you might get lucky and have a sight glass too. This will let you see the refrigerant, and ensure that you have a solid column of liquid. It will also usually have a moisture sensitive paper in there, that will change colors if you have moisture in the system. Refrigerant is clear, so most of the time it will just look empty.

ELECTRICITY

So that's the basic mechanical overview. So let's move on to the electrical side of things.
So this can be divided into two sides as well, there's a high voltage side, and a low voltage side.

The High voltage side is usually 208V-230V. Don't gently caress around with this with the power on. This is what powers the compressor and various motors.
The Low voltage side is usually 24V. This is your control voltage, that powers up the thermostat, and energizes the various contactors and relays when your system calls for heating or cooling.

So, this is a basic electrical drawing of a system:

This is a kinda bad example, but it's the best I could find on GIS. I'm too lazy to draw my own. This is using a mercury bulb stat too, so bear with me here.

So lets start on the control side of thing. You have your power coming in from your disconnect box, and it runs to the transformer, which steps it down to 24V.
Now usually you'll have two wires running off of there that go to a terminal board that you hook up your thermostat to, If you have a digital thermostat, you're going to need 24V to power it up, so you can use the screen, and such.

So let's start at the Thermostat. This is basically a big switch that lets you control the way it runs. You know how this basically works. But inside, where you hook up the thermostat wires, is were the action is.
On the baseplate you have bunch of different terminals, all designated with a letter. Each one of these controls an action on your system, and has a color coded wire to go with it. Thermostat wire comes in a couple different varieties, but normally you'll either have 5 conductor, or 7 conductor strands, depending on if you have a heat pump or not.



So, what do these letters mean? And which color goes where?

R: R is your hot 24V coming in from the transformer. This what will power up the rest of the connections. Usually uses the red wire.
W: Heat. Usually uses the white wire. Depending on the system, you may have more than one form of heat, so that's why you have W2, etc.
Y: Cooling, this will engage the compressor contractor, and start cooling. Usually the yellow wire.
G: Blower motor. This engages the blower motor relay and fires up the blower motor. Can be set to run with or without cooling running, but will automatically engage when calling for cooling or heat. Uses the green wire.
C: Common. Sends completes the circuit to the transformer. You need this if you have a digital stat and don't want to run batteries. Uses the blue wire.

Now, you see how it has a designation for heat pump and conventional? That's because the heat pump has some extra wires.
For the most part it's the same, R, Y, G, C, are all the same, but there are a few other:
O/B: This powers up the reversing valve. It usually always gets 24V, unless you have it in heat mode. Uses the orange wire.
W2: Aux heat. If you have a heat pump, you'll usually have an auxiliary source of heat, usually some electric heat strips, and this will call for those if your heat pump can't keep up or is in defrost. This usually uses a brown wire, but it can vary.
Y2: Cooling, again, this is if you have multiple stages of cooling. This will call for the second compressor to fire up if the first one isn't maintaining temp. Color of wire varies.
S1 and S2: This is if you have a remote sensor installed somewhere. This allows for the Tstat to read the temp in that section of the room.

Now, the thermostat wire usually runs to a terminal board in the air handler, and that will run the power to all the other contractors and relays in the system, but there are some other components in the control system. Safety components!

Inside the air handler, on the drain pan, you'll have a float switch mounted in there. This will usually be tied into the red wire, and will kill the system if it opens. This happens when the drain pan fills with water, usually because the drain line is clogged with slime. When this happens you'll get water dripping down out of the unit, and all over what happens to be below it. If the air handler is mounted in an attic or hanging from the ceiling then it'll usually fill up an auxiliary drain pan with like 100 gallons of water and some tech will have to come out and drain it 5 gallons at a time with a shop vac, because some moron jumped the float out. NO I'M NOT MAD.

Inside the condensing unit you'll have two pressure controls, a high pressure switch, and a low pressure switch. These will kill power to the compressor contractor if one of them opens, due to either excessively high pressure, or very low pressure, as both of those can kill a compressor. Usually if the high pressure trips, it's because the condenser coils are dirty and need to be clogged out. Low pressure can mean that you may have a leak. Or that the evap coil is clogged or iced over. If this happens, then that means you can also have liquid slugging back to the compressor, which is bad news.



MORE TO COME LATER ON! STAY TUNED!

ExplodingSims fucked around with this message at 19:43 on Jan 24, 2016

iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

Thanks for doing that, I was going to get around to writing something up eventually. Well done!

literally a fish posted:

Someone bring me a Rolls-Royce Merlin. I found a better supercharger.

E: The Subaru's A/C compressor has started going TAPTAPTAPTAPTAP when it's hot/operating. Is this because it spent a couple of weeks upside down (not being operated), or did it just died?

Could have gotten a slug of oil in the wrong spot from being upside down and bent/broke something when it started, or it could coincidence and just died. Send me a video of it on whatsapp if you think of it.

slap me silly
Nov 1, 2009


Grimey Drawer

I'm just here for the pictures and boy are they awesome.

Oh I've got a random question though. Apartment buildings are springing up all over the place around me. Each unit has its own little system (heat pump I guess?) but surely there is some additional stuff going on for ventilation. How is that usually handled in modern "just-meets-code" type of multiunit construction?

slap me silly fucked around with this message at 22:21 on Jan 24, 2016

immoral_
Oct 20, 2007

So fresh and so clean.



Young Orc

On the other side of HVAC, there's the getting that cooled/heated air to where you want it, in other words, duct work.

That's where I've recently started working. I got into a Sheetmetal Apprenticeship in September of last year. I went into the place to fill out the usual employment paperwork, and the shop foreman was going to have me start spot welding some fittings together, well, they got a call from the field about some stuff needing to be delivered to a job site. So the foreman put me in a truck and sent me to the fairground.

Turns out, my brand new place of employment got the bid for the new Expo Center at the State Fairground. It's a pretty good size building, 300ft by 600ft for the main expo area, and two wings on the north and south sides for sundry storage/restrooms/kitchens.

I knew nothing about duct work, beyond it supplies the ac and heating, so I got a crash course on shooting hangers, banging together duct, cutting it to fit, lifting it anywhere between 8'-14' with a rickety duct jack, and the ultimate fun, pookying it.

Well, that wasn't so bad, it was still warm, and there were walls up, so it blocked most of the ceaseless wind, and the roof was roughed in, so it blocked most of the beating sun.

Fast-forward 4 months, and it's cold, the wind is still ceaseless, but now we get to hang spiral across the Expo bay. But this isn't any regular spiral, we've got 60" that steps down across the bay down to 36" with a few oval-to-round fittings to go between the I-beams and the roof.

Have some pictures:
54" oval-to-round with an 8' joint to catch the hanger
This is actually 54"
54"
Another 54" joint and oval a few bays down
Here you can see the oval-to-round with the 54" going to the reducer that steps it to 60" that is running to the supply
Here you can see where that 60" turns down the the baffle that goes to the supply, we don't have anything hooked up yet because we don't have the square-round, but it's gonna be a whole mess of fun to attach.
I wish I had a better picture, but these are our units, with a pipefitter for scale. These are 490ton units, and I forget exactly how many we have, but there are at least 6 of that size, and a few smaller ones.

e. images work now

immoral_ fucked around with this message at 22:32 on Jan 24, 2016

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Fuuuuuck ductwork man. On thing our company does not do is ductwork, and I couldn't happier.
Sometimes we have to do a bit, like when putting a new sideflow unit in place, or a split, (or if we accidentally burn down a 30' section of duct) and it always sucks. You get fiberglass all over you and mastic and poo poo.
I feel your pain man. Just wait til summer hits and you're working in a 120* room with fiberglass bits raining down on you.

immoral_
Oct 20, 2007

So fresh and so clean.



Young Orc

Lucky for me, the majority of what we've hung is unlined. Now, yeah all this spiral is lined, but it's not that loose fiberglass poo poo like what they hung one the wall in the one picture, but yeah, it's still annoying.

STR
May 12, 2006

I thought I was a nice jester


slap me silly posted:

I'm just here for the pictures and boy are they awesome.

Oh I've got a random question though. Apartment buildings are springing up all over the place around me. Each unit has its own little system (heat pump I guess?) but surely there is some additional stuff going on for ventilation. How is that usually handled in modern "just-meets-code" type of multiunit construction?

Definitely not someone who works in this, but I've lived in entirely too many apartments.

Most apartment sI've lived in with central HVAC - those with individual HVAC units and also those with chillers/boilers - always had an air handler somewhere in the apartment. Generally in the bathroom ceiling, with a return air duct in a hallway or common area. The air handler had heating coils if the system didn't rely on a chiller/boiler, otherwise it was just a fan and a small radiator (but still ducted). I've seen the units placed in hallway ceilings or walls too. There's an access panel to get to them.

Most of the places I've lived used a simple outside a/c unit with electric heat inside, aside from a couple of places with a chiller. I've only seen heat pumps in one apartment complex, though the entire property had been gutted and rebuilt (keeping only the exterior walls and rough door/window openings), and the management company wanted to get some kind of LEED rating. That place still had electric heat for days that it was too cold to run the heat pump.

One exception was a large 2 story apartment that my dad lived in, it had a traditional gas furnace + air handler combination that you expect in a single family home. But that was an apartment that was bigger than some houses, and also a bit older (1970s).

angryrobots
Mar 31, 2005



Oven Wrangler

Cool thread, cool pictures. I did HVAC and electrical straight out of high school for 4 years. Learned a lot that has saved me a pile of money over the years.

So when is somebody going to make a residential geothermal package unit for exterior installations? I'm definitely in the market if one exists. It seems like an obvious solution, not everyone has a basement or mechanical room. I don't want to stick it in the crawlspace, probably wouldn't fit anyway and too hard to service.

iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

slap me silly posted:

I'm just here for the pictures and boy are they awesome.

Oh I've got a random question though. Apartment buildings are springing up all over the place around me. Each unit has its own little system (heat pump I guess?) but surely there is some additional stuff going on for ventilation. How is that usually handled in modern "just-meets-code" type of multiunit construction?

I don't know much about residential codes and installs since I do commercial/industrial, but I'd imagine it's a small unit with a/c + gas heat like my apartment.

Also, have some pictures of a failed babbit sleeve bearing and scoring on the shaft! This bearing was absolutely bone dry, but that doesn't make sense as the system won't run if it doesn't see oil pressure and there were no clogs in the 3/8 line that feeds oil to the bearing. The pressure transducer 10 inches away from the bearing tests fine. More investigation required, but now to figure out how to get a 1600 pound motor out of this basement, crate it up, and ship it to North Carolina to be rebuilt. Fun fun!

Shaft diameter where the bearing rides is around 6.5 inches.



The lighter scoring is from the labyrinth seal rubbing, the deeper scoring inside that pocket is where the bearing sits.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




slap me silly posted:

I'm just here for the pictures and boy are they awesome.

Oh I've got a random question though. Apartment buildings are springing up all over the place around me. Each unit has its own little system (heat pump I guess?) but surely there is some additional stuff going on for ventilation. How is that usually handled in modern "just-meets-code" type of multiunit construction?

Every cheapo apartment place I've seen going up around here just have spilt-systems for every apartment. Usually some garbage tier Goodman junk or something, but that's about it. I'm not an expert in this though, I don't do installs. I don't think you really need much else. It's not like they're worried about building air balance or anything like that.


angryrobots posted:

Cool thread, cool pictures. I did HVAC and electrical straight out of high school for 4 years. Learned a lot that has saved me a pile of money over the years.

So when is somebody going to make a residential geothermal package unit for exterior installations? I'm definitely in the market if one exists. It seems like an obvious solution, not everyone has a basement or mechanical room. I don't want to stick it in the crawlspace, probably wouldn't fit anyway and too hard to service.

I'm not sure how outdoors rated these are, but ClimateMaster has a selection of products, both spilt and package, that look like they'd be pretty hardy outdoors. Again, I'm not an expert, as I've never really worked with geothermal stuff, but I've read up a lot about these guys. Seems pretty solid. http://www.climatemaster.com/index


In other news, sometimes contactors fail. Usually it's just the coil dies and they won't engage. But sometimes, contactors fail spectacularly.


Bet that made a noise.

STR
May 12, 2006

I thought I was a nice jester


Serious question, what's wrong with Goodman? They seem to have a good warranty, and several friends in the HVAC field have told me that they're one of the better budget brands.

angryrobots
Mar 31, 2005



Oven Wrangler

Same. My impression was that they were a good simple, reliable unit.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Every experience I've had with Goodman has been a pain in the rear end. They use cheap parts, have very thin sheetmetal panels that never fit right and can be a pain in the rear end to take apart.
Maybe we just got unlucky, but it seems like most Goodman units we install have something go wrong within the first year of install. We've even had one blow out two contactors right out of the box. I wouldn't say their warranty is anything special either, seems to be a pretty standard one for the industry.

Mind you, most of my experience with them is in the commercial package unit side, but there's nothing about Goodman that makes me want to buy one.
But I guess this kinda gets into Chevy vs. Ford type territory.

That's not to say that most of the other brands are too great.
Carrier has problems with panels fitting right. Trane makes blower wheels a pain to work on.
Lennox is pretty great all around though. They seem to build units that are designed around being serviceable.

Personally I'm a big Trane fan though, at least for residential stuff. They've got a lot of cool tech stuff going on.

ExplodingSims fucked around with this message at 03:01 on Jan 29, 2016

~Coxy
Dec 9, 2003

R.I.P. Inter-OS Sass - b.2000AD d.2003AD

Questions I don't know whether are answerable:

1) Home ducted aircon with a zone per room, close the doors of the cool rooms or open them?

If you close the doors you don't waste cooling power on the unused rooms.
If you open the doors the cool air can return to the intake.

2) What should be done with useless vents? There is a vent in the master bath that uselessly blows cool air so the master bedroom is positive pressure and leaks into the roof space. I've closed the louvres as best I can but is there something else to be done about that?

immoral_
Oct 20, 2007

So fresh and so clean.



Young Orc

You can buy magnetic covers to put over floor vents to help with that.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




So I promised pics of a proper compressor room, and today I finally had the opportunity to grab some pics.
Compressors


Backside. Note the ice buildup. That will come up later.


Compressor. This are fairly new Biltzer compressor. This store is a newer store, and has a lot of high end tech stuff running all the refrigeration stuff. Also the only store that uses shaft couplers for direct drive action. Which is slowly destroying the shaft seals and causing oil leaks!


Theses are also what are know as semi-hermetic compressors. You can take these apart and rebuild them. They're pretty similar to a car motor, they have heads, pistons, and a crankshaft.

Motor.

I also just installed that leak detector on this side about a week ago.

Pipework Nightmare.


Now this is why we were out here. That black thing there is the oil reservoir for the A rack. There's a identical setup on the other side. Anyways,we had to come in and add oil to the system, which means pumping all the refrigerant out of the that, valving it off, and then hand pumping 3 gallons of oil into it. Not a fun time. And as it turns out, it's leaking from there too!

So about that ice building up you see in the other pics. Now, some ice buildup is normal in refrigeration, you get areas where the insulation on the pipes doesn't quite cover it all the way, and it lets some air into direct contact with the pipe. Well in this case, it's way too thick, and was starting to buildup on the compressors. On these style compressors, that's a very bad thing, as liquid refrigerant can't be compressed, so when you get floodback like that, the refrigerant can cause the headgaskets to blowout, or worse destroy the pistons or conrods.

So what was causing this?
An evap had all it's fans down. Something was causing it to trip the breaking back in the panel.

The one on the farside there.

Now, this is a bad thing, because when you have refrigerant being metered through a system, it has to pick up heat to keep in a gas form. This is accomplished by dragging air across the coils, and having it absorb the heat from the air. But when the fans go down, the refrigerant flow doesn't stop, and it will still cool the pipes, and cause ice buildup. Ice is an insulator, so it will keep heat transfer from occurring with the outside air, causing the refrigerant to stay cold, and condense back into a liquid. You can see above for why this is bad news for the compressors.

So, we had to climb on up there and figure out what went wrong.

Hmmm, everything looks ok here.

Wait, what's that on the disco switch?


Oh dear.


It would appear that someone didn't seal the box properly, air got in, formed ice, and shorted it out.

ExplodingSims fucked around with this message at 00:57 on Jan 30, 2016

literally a fish
Oct 2, 2014

German officer Johannes Bolter peeks out the hatch of his Tiger I heavy tank during a quiet moment before the Battle of Kursk - c:1943 (colorized)


Slippery Tilde

My trick is a small sheet of metal/plywood/plastic, a towel, and a weight of some kind.

E: ^^^^ happened while I was posting. DUUUUUUDE. Awesome.

literally a fish fucked around with this message at 00:38 on Jan 30, 2016

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




~Coxy posted:

Questions I don't know whether are answerable:

1) Home ducted aircon with a zone per room, close the doors of the cool rooms or open them?

If you close the doors you don't waste cooling power on the unused rooms.
If you open the doors the cool air can return to the intake.

2) What should be done with useless vents? There is a vent in the master bath that uselessly blows cool air so the master bedroom is positive pressure and leaks into the roof space. I've closed the louvres as best I can but is there something else to be done about that?

Ok, so there's a lot to ask here.
1. When you say a "zone per room" do you mean that you have a zoning control system? Like you have electronic dampers and individual temp control for each room?
I mean, in general you want to keep airflow as unobstructed as possible, because you're not "wasting cooling power", you're making the blower work that much harder to suck all the air back into the system.
I'm not quite sure what your issue is here? Are your rooms too cold?

2. Why do you say this is useless? You want your rooms to be in a slight positive pressure. Hot air moves from hot spaces to cold spaces, so if you don't have a positive pressure in the building, then you're going to be sucking hot air in.
If you're that worried about it, then you're better off sealing up the leaky areas in your ceiling or whatever.

ExplodingSims fucked around with this message at 02:24 on Jan 30, 2016

~Coxy
Dec 9, 2003

R.I.P. Inter-OS Sass - b.2000AD d.2003AD

ExplodingSims posted:

Ok, so there's a lot to ask here.
1. When you say a "zone per room" do you mean that you have a zoning control system? Like you have electronic dampers and individual temp control for each room?
I mean, in general you want to keep airflow as unobstructed as possible, because you're not "wasting cooling power", you're making the blower work that much harder to suck all the air back into the system.
I'm not quite sure what your issue is here? Are your rooms too cold?

2. Why do you say this is useless? You want your rooms to be in positive pressure. Hot air moves from hot spaces to cold spaces, so if you don't have a positive pressure in the building, then you're going to be sucking hot air in.
If you're that worried about it, then you're better off sealing up the leaky areas in your ceiling or whatever.

First, thanks for replying. Yes, our system is individual temperature control.
The reason I ask these questions is only about maximising efficiency, because it's fairly expensive to run obviously.

1. If the door to the bedroom is open, then cool air is flowing out of the room and into the hallways. So this is better than sealing the bedroom?

2. It's useless because I don't want my bathroom to be air conditioned. The cool air just goes through the fart fan into the roof. The master bath vent is always blowing if the master bedroom zone is turned on.
Also, there are vents in the hallways that always blow cold air but I'm guessing this is by design since the intakes are in the hallways.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




1. Well if you have electronic dampers then they should be throttling the airflow down automatically as each individual tstat is satisfied.
But anyways, yes, leaving doors open is better. Air is going to be sucked back into the return either way, so reducing the airflow is just going to make the blower work harder.
Unless of course you have individual returns for each room, or if you have little jumper ducts over the doorframes that deliver the air back to the central return.
In which case it doesn't matter quite as much if you open or close the doors.

2. If your vent is running all the time it sounds like something is wired wrong. You do want your bathroom to be air conditioned, it's going to help with humidity control.
You may loose a bit of air through the vent, but that's ok. When designing an duct system this is taken into account, using the vent a method to remove air from the room.
This has to due with humidity control, as you'll most likely be sucking the hot humid air back to the air handler, which you don't want, so you can just blow it out.

STR
May 12, 2006

I thought I was a nice jester


e: nevermind

STR fucked around with this message at 13:16 on Jan 30, 2016

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




In an effort to keep this thread alive til summer, have some more rack refrigeration stories!

So today we were at a different store, for another call. This one's a bit older, so it has a older style stuff than the other store.
First off, the compressor room, which is less of a room, and more of a prefab'd building that keeps trucked into the store.


Bottom is compressors, top is all the store's electrical.



These are the belt driven compressors. The belts are about 6" wide and have 5 tracks



So, why were we here? Similar reason as last time, ice buildup:
(Spoiler: Pictures get lovely cause I'm literally in a display freezer with about 5' of standing room


As was previously established ice is bad because floodback.
But is this case, due to evap design, it's bad because it will cause the fan blades to bind up and burn out the motors.
But, since this is a supermarket and people are around and you have to worry about product getting wet and spoiled, you can't run a hose to melt down the ice, so you have to do the next best thing:


A combo of that and chipping away at the ice managed to break a good chunk of it free, enough that we can shut off the liquid flow to it and let it air defrost for a bit to de-ice.
Oh, and you know what happens to big, 6" thick chunks of ice when they start melting? Gravity takes over, and...

You get this raining down.

Why air defrost, because the defrost heaters are down, fun stuff. How can you tell? You have to amp out each heater strip and see if the one you suspect is drawing at all.
In this case it wasn't But, in case you were wondering how many heaters and fans might be in one store:


Each one of those contactors powers a either a fan, or a heater strip. There are 5 of these panels.

ExplodingSims fucked around with this message at 22:35 on Feb 7, 2016

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




So Friday was a fun day. What was supposed to be something that could be done in about 4 hours took about 9 hours due office fuckery.
We were out working in one of the oldest stores we service. This one's laid out a bit differently than most stores, in that the rack room is an actual room, they use older equipment, and everything is gross and covered in 3" of grease.
MOVING ON.

This is the dinosaur in question, a big ol' GE Motor that has open windings.
Note that these are also the older style compressors which also pretty big.

Now see those boxes in front of the motor there? Those are oil pressure controls, and the pressure controls. Those will prove to be a pain in the rear end later

One nice thing about this store is that it offers you a chance to get behind the compressors, and it makes it much easier to change belts or do a shaft seal.
Speaking of belts, there's a lot of them.


So these motors are heavy. Two people can lift them, but barely, and remember those pressure controls I mentioned earlier? Yeah, those get in the way, and if you crush one of those you're hosed.
Normally you could replace if they happened to get damaged, but in this case it would be worse. See those ball looking things on the top of the compressor? Those are valves that shut the flow of refrigerant off from the compressor, so you can isolate it for service. One of those is damaged, and will let refrigerant still seep by, so if you bust a pressure control, you still get refrigerant blasting out. This is not a good thing for a variety of reasons.

Now in most rooms they weld an I beam to the roof so you can hook up a hoist and move motors or compressors around with relative ease. But this store doesn't have a proper compressor room, it's walls with a drop ceiling.
So, you sometimes have to make your own solutions.


And that thing was still a bitch to navigate over to the cart.


Alright, new motor went in easy enoug- Wait, that's not right.


Ehhhh, nothing's ever easy here.


Biggerized motor:


Now since this is heavy duty, very high voltage (460V) stuff, you need heavy duty equiptment.
Enter the contactor, Gojo bottle for scale:


And wire it up and you're good to go!


Then wire it again because you mixed up the legs and running backwards!

ExplodingSims fucked around with this message at 22:34 on Feb 7, 2016

literally a fish
Oct 2, 2014

German officer Johannes Bolter peeks out the hatch of his Tiger I heavy tank during a quiet moment before the Battle of Kursk - c:1943 (colorized)


Slippery Tilde

Most of your images won't load for me

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




De-hugeified the pics a bit. Should load a bit better now.

literally a fish
Oct 2, 2014

German officer Johannes Bolter peeks out the hatch of his Tiger I heavy tank during a quiet moment before the Battle of Kursk - c:1943 (colorized)


Slippery Tilde

ExplodingSims posted:

De-hugeified the pics a bit. Should load a bit better now.

This actually turned out to be my ISP/web browser throwing a hissyfit

Awesome photos though. The juxtaposition of the new motor with the old compressor is particularly amusing to me

iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

Nice work, Sims!

I've been busy as hell and not doing anything picture-worthy. Parts came in for the motor on that Trane Centravac I've been working on, so reassembly starts tomorrow. I'll snap pictures if anything interesting arises

The Slack Lagoon
Jun 17, 2008



How stupid is this register/return/thermostat placement combo?

That return is the return for the entire apartment.

I can feel the hot air just getting sucked into return and this room just stays cold





How bad of an idea is this? Made a hood type thing so air gets pulled from lower in the room. Didn't sound like it was putting any stress on the furnace.

The Slack Lagoon fucked around with this message at 17:28 on Feb 14, 2016

Chillbro Baggins
Oct 8, 2004
Bad Angus! Bad!


My father was an HVAC tech from 1972 to whenever the gently caress he retired (2008-ish). Was service manager for his big brother's HVAC company from the time they came back from being Green Berets in Vietnam until my uncle retired, and Dad worked for another HVAC company for a few years until he retired. I apprenticed with dad for a few summers until I decided to work for Mom remodeling grocery stores.

Today Mom and I were in a store during a good 'ol East Texas thunderstorm, and the power went out.

Fact #1: A grocery store has just enough of a backup genset to run the lights and computers.
Fact #2: A grocery store on generator power is the epitome of the ol' deafening silence. Without the Muzak and the background hum of the ~kiloton (just guessing there) of refrigeration running the freezers, meat/produce coolers, and A/C, it gets rather creepy. It's one of those things you don't notice until it goes away, sort of like how you tune out the sound of your fridge, computer fan, and A/C at home, but when the power goes out the lack of background noise wakes you up, but on a grand scale.

Also they turn the automatic doors to "exit only" and flip the metaphorical sign in the window to "closed" (in practice, they had the newbie cashier stand outside the door and shout "we're closed!" at customers pulling in to the parking lot) when the power's out for half an hour, because after that point, opening the freezer doors costs them a lot of money/shortens the shelf life of the ice cream.

Edit: Fact #3: the standard policy for tornadoes is to herd all the customers and employees into the backroom freezers. The severe weather will pass before anybody dies from hypothermia, and they probably won't die from hypothermia given that the storm has probably already killed the power and there's plenty of ice cream to eat before it goes bad.

Chillbro Baggins fucked around with this message at 03:32 on Feb 16, 2016

sirr0bin
Aug 15, 2004
damn you! let the rabbits wear glasses!

We just got the stator, rotor and impellers from our Trane CentraVac 900 tonne back from getting rewound and dipped and all that good stuff. The entire unit is being overhauled, our 700 tonne was just done last year. Problem free for the next 10 years, right?

iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

very nice! I'm just starting a rebuild of a 1280 ton centravac at a hospital. Trane had it apart 3 years ago to do bearings but its leaking so the hospital is having us come in and fix what they didn't get right. Going to be very interesting, the motor weighs 3200lbs and there is very little room to work.

slap me silly
Nov 1, 2009


Grimey Drawer

drat! That's . . . not small.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




So, after a span that's been both crazy busy, and very slow, I'm back with fun new stuff.
So you may remember these little guys who keep your meats cold:


Well, something has to keep them cool too, otherwise they'll over heat and blowout their gaskets or cook their oil or other fun things. Now normally this has been done with a gycol plumbing system. Which sucks because it means getting extra pumps involved and things rust and jammed up and you get Smurf blood all over everything when you do service work.

Yeah, these guys can gently caress right off.

So, they've since come up with something better, enter the refrigerant cooled head:


This works like a small evaporator that wicks heat away from the heads. There's a TXV that feeds from the main liquid line in the compressor room, and feeds all those twisty copper lines.
Also, this comes with a new and improved oil cooler! Though as you can see, this adds quite a bit of piping to the system. I am not looking forwards to they day one of these compressors has to be changed out.

But, even these heads are far from perfect. So the heads are made of aluminum, the compressors out of steel, the lines out of copper, and the fittings out of brass.
So you guess what happens when you mix all those metals together in an environment with crazy temp fluctuations?

Corrosion.

So the manufacturers solution was to anodize the heads in this snazzy blue color.




Delivery McGee posted:

My father was an HVAC tech from 1972 to whenever the gently caress he retired (2008-ish). Was service manager for his big brother's HVAC company from the time they came back from being Green Berets in Vietnam until my uncle retired, and Dad worked for another HVAC company for a few years until he retired. I apprenticed with dad for a few summers until I decided to work for Mom remodeling grocery stores.

Edit: Fact #3: the standard policy for tornadoes is to herd all the customers and employees into the backroom freezers. The severe weather will pass before anybody dies from hypothermia, and they probably won't die from hypothermia given that the storm has probably already killed the power and there's plenty of ice cream to eat before it goes bad.

I seriously cannot think of anywhere I'd want to be less than in a walk in during a storm. Seriously, those are made out of paper thin metal and foam. They have no support other than being held to the ceiling by bailing wire, and the walls. They''re not even glued or anything either, just held in place by cam locks. You'd be surprised at how light and flimsy those panels are.

Well, ok, some older boxes may have some wood as well, but they still have very little in the way of support. If anything serious happened to the roof or the building those things will collapse so fast.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




This is your daily reminder, gently caress SALT.



Surprisingly, this thing still cools just fine. Head pressure's a bit high though.
The only thing wrong with it was a defrost board, and LOL Heat in Florida.

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iForge
Oct 28, 2010

Apple's new "iBlacksmith Suite: Professional Edition" features the iForge, iAnvil, and the iHammer.

I haven't been up to anything worth posting, really. I got pulled off that chiller rebuild job, so no pics of that. Spent almost a month at a data center going through 96ish 30 ton Liebert units, 10 air handlers, 3 rooftops, making a list of the needed repairs, and then fixing most of the stuff. Not allowed to take pictures in there by their security policy so I don't have pics of anything. Mostly replaced chilled water valve actuators, bearings, and fixed a few leaks on the coils.

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