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MRC48B
Apr 2, 2012



Glad I found this thread, I currently work Residential, but was thinking about moving into commercial and refrigeration.

Content:

https://www.youtube.com/watch?v=NO8eOjQAKUg

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ExplodingSims
Aug 17, 2010

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




MRC48B posted:

Glad I found this thread, I currently work Residential, but was thinking about moving into commercial and refrigeration.

Content:

https://www.youtube.com/watch?v=NO8eOjQAKUg

This pretty much sums up my feelings on working on rooftops.

In other news, I went through my phone and found some pics I've been meaning to share.

Why size the evap correctly for the space you're cooling when you can just do this?



And then there was this work of art:



I'm done. Nope, not even diagnosing the system. New compressor time.

Armacham
Mar 3, 2007

Then brothers in war, to the skirmish must we hence! Shall we hence?

Can I ask you guys a quick question about wiring? My wife and I want to get one of those newfangled wifi thermostats, but our HVAC is old as hell, so we don't have a CWire. I looked at the wiring diagram and it looks like there are a couple of blade terminals marked with a C. Should I be able to use one of those? For reference we are looking at the ecobee3 and our HVAC is a Rheem RRNL series. The wiring diagram I have matches the one on page 66 of this manual. http://www.rheem.com/docs/fetchDocu...b9-c1d235364323


The unit is on the roof, so I haven't gotten a chance to actually look at the control board itself, other than through the diagrams.

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

C in that wiring diagram means Common, or (as you can see by the line running from the left hand C lug to the little symbol that looks like a rake) the ground wire.

You don't need a C wire, the 4 wires running to your current thermostat should be all you need. A quick check on the Nest website, for example, shows that just R, Y, G, and W will work just fine with a Nest, and all the other universal wifi thermostats should be the same. The other wires are present on the wifi thermostat bases for compatibility with systems that DO have them present; yours doesn't, it'll be fine.

Armacham
Mar 3, 2007

Then brothers in war, to the skirmish must we hence! Shall we hence?

My understanding was that the ecobee3 does require a C wire. It does include a kit that lets you operate without running a whole new wire, but you still have to hook the power extender up to the C wire terminal at the control board.

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

Interesting. I guess they're using that to avoid the parasite power issue that some Nest systems have. Use the 2nd C lug from the left, the one that connects to the transformer.

ExplodingSims
Aug 17, 2010

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




If it's like every other digital stat out there, you need the common wire if you don't want to have to use batteries on it.

It'll still work, but you'll just have to change batteries every once in a while.

Armacham
Mar 3, 2007

Then brothers in war, to the skirmish must we hence! Shall we hence?

Thanks for the information! The battery on the ecobee is just for maintaining the settings in case of a power outage. It won't run for more than a few days without power.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

literally a fish posted:

C in that wiring diagram means Common, or (as you can see by the line running from the left hand C lug to the little symbol that looks like a rake) the ground wire.

You don't need a C wire, the 4 wires running to your current thermostat should be all you need. A quick check on the Nest website, for example, shows that just R, Y, G, and W will work just fine with a Nest, and all the other universal wifi thermostats should be the same. The other wires are present on the wifi thermostat bases for compatibility with systems that DO have them present; yours doesn't, it'll be fine.

A Nest will "work" but the internal battery will only charge when you call for heat/cool/fan without a C wire. It's generally not a great way to go and ends up with you needing to take the thing off it's base and charge it with a USB cable occasionally.

STR
May 12, 2006

I thought I was a nice jester


No C wire on my install, and my Nest has yet to ever ask me to charge it.

During the late fall and early spring, we'll often go days without running the HVAC.

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

Without a common wire, Nest will leak a small amount of current through the control terminals to charge itself even when you don't switch on the HVAC. This has caused some issues with some systems never shutting off because nest's small charging current is enough to turn on the relays in some setups. If you have a look on their forums you can find some people complaining about this, the good news is that Nest policy seems to be that they'll cover the cost of getting a licensed tech to install an add-a-wire kit.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

literally a fish posted:

Without a common wire, Nest will leak a small amount of current through the control terminals to charge itself even when you don't switch on the HVAC. This has caused some issues with some systems never shutting off because nest's small charging current is enough to turn on the relays in some setups. If you have a look on their forums you can find some people complaining about this, the good news is that Nest policy seems to be that they'll cover the cost of getting a licensed tech to install an add-a-wire kit.

That must be a new-ish thing (in comparison to when I got mine/was doing the research on them). Originally they definitely did not do this and people who used them for heat only and.or had long springs/falls where they din't need to run the system were finding their stats dead when the needed them again. (cue: "its freezing/100 degrees and my nest won't turn on" posts all over the forums)

ExplodingSims
Aug 17, 2010

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




Yeah, I've never heard of a Tstat being able to charge off of just the 24V. Every digital stat I've installed needed a common to run without batteries.

But we don't use nest thermostats at all, so I guess that must be something only they do.

Armacham
Mar 3, 2007

Then brothers in war, to the skirmish must we hence! Shall we hence?

I know my Rheem system's manual states that it is not compatible with "power stealing thermostats" and it was installed in 1998.

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

I'm pretty sure this is a feature that's exclusive to the Nest, and maybe the newer generations of Nest only - here's an article from a tech journalist that details the issue http://www.businessinsider.com.au/n...-problem-2014-1

As mentioned it's an idea that's been around for a while (and makes sense if you're using bare relay coils as your control inputs, you could conceivably run 10mA through those without turning them on) - but Nest appears to be the only ones who are still using it, since it's clearly caused a nonzero number of problems (and Ecobee for example just include an add-a-wire kit)

STR
May 12, 2006

I thought I was a nice jester


We have a 2nd gen Nest, FWIW, given to us by our power company. Just double checked, looks like I registered my account with Nest right at 3 years ago.

They hadn't started the free tech call-out yet, I remember the manual saying you would need to pay to have someone come out if that were the case. We actually have 8 conductor cable in the wall, so if I did need to connect a C wire, it wouldn't be a big deal. As to how we wound up with 8 conductor cable... the house was originally setup with a heat pump w/gas furnace backup, but the original owner of the house decided to rip out anything related to a heat pump and make the furnace the primary heat source. The original ac/heat pump was a massive clusterfuck of hosed wiring and hacks - the only thing they left inside it that was related to heat pump operation was the reversing valve (but cut the wires right at the valve). No idea why they did that, and I'd still like to kick their rear end for it.

Armacham posted:

I know my Rheem system's manual states that it is not compatible with "power stealing thermostats" and it was installed in 1998.

We have a York furnace from 1994 (original to the house), and a mid to late 00s Trane a/c. Manuals are long gone, but it's been working fine with the Nest for 3 years now. There's a little bit of a buzzing from the furnace now, but beyond that it hasn't protested. One of these years I'll probably go ahead and hook up a common wire.

STR fucked around with this message at 08:02 on Apr 14, 2016

angryrobots
Mar 31, 2005



Oven Wrangler

I'm surprised to see as many HVAC knowledgeable persons in here using a nest tstat at their home.

I get the advantage for the "set it and let it work" ability to get some efficiency/comfort for the average homeowner.... Is there some other advantage it has over my 7-day programmed tstat? I know it has an occupancy sensor, but rarely do I want it to run outside of normal schedule based on occupancy.

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

It looks up the weather forecast and will run the heat or AC in advance of the weather cooling down / heating up so that you don't have to go manually turn it on, blah blah... I don't actually use one myself (still not available in Australia) so someone like STR should be along shortly with some more info

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

angryrobots posted:

I know it has an occupancy sensor, but rarely do I want it to run outside of normal schedule based on occupancy.

That was exactly it for me. It's in my home office (in an outbuilding) not my home.

I also like that I can turn the "away mode" off from my phone when it freaking cold outside before I take a shower and walk out to the office while also having a min/max threshold (always running computers in there, so I'd like to keep it below 90, paint in the cabinets so also above freezing).

I'm not always on a regular schedule because of the type of work I do, so it's perfect. I also have radiant heat and forced air gas in there as a second stage. Not many t-stats handle radiant well (they tend to overshoot). This does. When I am on a regular schedule it's smart enough to start the radiant long enough before time to actually get the office up to temp without using second stage based on room temp/downloading the weather forecast/i don't know what the gently caress. But it does.

I did look into using commercially available occupancy sensors (for lighting) and a bunch of relays. This was the easier and more reliable path at the time. I'd rather more control than this super "consumery" thing, but I have to say.....for the most part it just does what it says.

angryrobots
Mar 31, 2005



Oven Wrangler

I can absolutely see the advantage in your case. Interesting about the way it is able to keep it within range with your 1st stage heat.

I didn't think about that... My Honeywell tstat is advertised as having algorithms and adjusting "on" time to hit your setpoint, but clearly it's nowhere near the accuracy of the nest. I just accepted the occasional "dumb" activity of the tstat as the way it is. Mostly it gets especially confused when you have daily wide temperature swings in the spring/fall. Often I just turn it off this time of year.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

angryrobots posted:

I can absolutely see the advantage in your case.

As much as it works for me......isn't this an edge case? I can't imagine my usage is typical.

( yeah, I know I kinda defended it before...but I get it...what is the mass market use case that it's superior at?)

angryrobots
Mar 31, 2005



Oven Wrangler

I think we're on the same page with that? That's why I was surprised to see so many in here that seemed to use it (and you in particular, but I didn't know your specific usage).

I suppose it makes sense when I've recommended a (dumb) programmable thermostat to everyone when it's come up, and I know exactly no one who has acted on it. I'm sure it's far more efficient than leaving the temp at your comfort zone all the time, like so many people do.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

I guess in that respect the "killer" nest feature is that it learns your preferences. If you adjust the temp for a few days/weeks it will autoset the schedule for you.

So basically for people who can't be arsed to read a manual and program a thermostat.

Seems like an expensive toy if that's what it' getting used for.

I've got a regular old programmable t-stat in the house. I don't see the value in putting a nest in there because it's a pretty regular schedule. I set it once a few years ago and.......well, that's all. It just does what it's supposed to.

Motronic fucked around with this message at 21:41 on Apr 15, 2016

ExplodingSims
Aug 17, 2010

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




I don't really see the appeal of the Nest. I get where it's coming from, at least from the efficiency standpoint, but really, your AC is on or off. Unless of course you've spent the money for the really crazy effeciency boosts in the form of ECMs, Variable speed compressors, multi-stage units, etc, then you're not really getting a huge gain.

Motronic posted:

I did look into using commercially available occupancy sensors (for lighting) and a bunch of relays. This was the easier and more reliable path at the time. I'd rather more control than this super "consumery" thing, but I have to say.....for the most part it just does what it says.

I think might want to take this to even more of an extreme. When I build my own house I'm thinking I'm going to drop the cash for a Danfoss AK-SC255 or something similar, to run everything.

http://products.danfoss.com/product...tem-controller/

These things are pretty great. We use these at all the stores we work at and it's a one-stop place for everything. A/C, Heat, Sprinklers, lights, everything can be controlled from the one box. And you can have up to 99 relay boards, that each about 9 relays and sensor inputs on them, so you can run quite a bit all at one. So you can monitor pressures, supply temp, return temp, Water temperature, set alarms, monitor run history, all kinds of fun stuff.

Mind you none of this is cheap, but it is a great way to keep on top of it. And I'm sure there's some turbo-nerd who'll explain how this can all be done with like arduinos or something, but it's nice to be able to have it all in one finished, easy to use package.

You can also go on Danfoss's website and download the software to play around with the controller and set up your own programs. It's pretty neat.

Motronic
Nov 6, 2009


MOTRONIC FOR MODERATOR, MAKE AI GREAT AGAIN


Grimey Drawer

Oh hell yeah. Full on building automation controllers kick rear end.

Just open your wallet and be prepared to do the equivalent of what would now be scraping up a computer that has a serial port and can still run DOS 6.22 with a working floppy drive in 10-15 years to control it because they will abandon the interface/software for the next best thing long before it's useful life is over.

angryrobots
Mar 31, 2005



Oven Wrangler

Motronic posted:

I've got a regular old programmable t-stat in the house. I don't see the value in putting a nest in there because it's a pretty regular schedule. I set it once a few years ago and.......well, that's all. It just does what it's supposed to.
Same. I think it's the same sort of appeal that any new gadgetry has for some people, with the added feature of possibly saving money.

The one thing I think a programmable tsat could use, is an outside temp sensor. I know some have it just so it can display outdoor temp on the tstat, but afaik none of them incorporate the information into its operational threshold.

If I'm wrong about that, somebody let me know, cause I'd install one.

Armacham
Mar 3, 2007

Then brothers in war, to the skirmish must we hence! Shall we hence?

angryrobots posted:

Same. I think it's the same sort of appeal that any new gadgetry has for some people, with the added feature of possibly saving money.

The one thing I think a programmable tsat could use, is an outside temp sensor. I know some have it just so it can display outdoor temp on the tstat, but afaik none of them incorporate the information into its operational threshold.

If I'm wrong about that, somebody let me know, cause I'd install one.

Supposedly the ecobee takes weather forecasts into account as part of the smart recovery feature.

ExplodingSims
Aug 17, 2010

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




angryrobots posted:

Same. I think it's the same sort of appeal that any new gadgetry has for some people, with the added feature of possibly saving money.

The one thing I think a programmable tsat could use, is an outside temp sensor. I know some have it just so it can display outdoor temp on the tstat, but afaik none of them incorporate the information into its operational threshold.

If I'm wrong about that, somebody let me know, cause I'd install one.

I don't think most thermostats do that since there's not a whole lot to gain from it. Nothing you can't do yourself anyways.
I might be a bit biased about that since I tend to keep my house's Tstat locked at around 73*, because ~Florida Humidity~

Although some commercial package units do use an outdoor temp sensor to their advantage. Lennox units use it to engage free cooling when the temp is low enough.
Basically they lock out the compressors, and open the fresh air dampers 100% and just let the outside air flow through. You get cool, filter air with no compressor.
At least until the sensor fucks up or the economizer breaks. (Or the store requires you to screw all the dampers 100% shut)

Now, if could work a fresh air intake with motorized dampers into your home's system, then you could certainly get a pretty cool thing going.
Throw a filter on there and get all the fresh cool air you want! I know Trane makes a part just for this, and I'd assume a few other companies may as well.

And before someone starts sperging out attic fans, no, those are terrible since they put the building in a negative and just suck dirt and pollen and everything else in.
At least with fresh air intake you're blasting air out.

angryrobots
Mar 31, 2005



Oven Wrangler

Yeah, I was thinking mainly of days where we have wide temperature swings, and the tstat has the unit unnecessarily running in heat at the recovery time.

Yes, it's something I can turn off myself, but you could say that about every programmed tstat function.

Kurr de la Cruz
May 21, 2007

Put the boots to him, medium style.


Hair Elf

I installed one of those add-a-wire kits and it seemed to work great for about week. Then last night the AC would kick on, there'd be a weird buzzing sound, and then 30 seconds later it would kick off. It kept doing this until finally it just stopped altogether.

I cracked open the furnace to find that it has a 5A automotive fuse in there, and sure enough, it was blown.

A quick trip to the store for a box of fuses, I replace the fuse, power everything back up and the fuse blows immediately.

Thinking it's the add-a-wire doing it, I remove it and switch back to the old battery powered thermostat.

Power it back up and boom. fuse blows again. (That's 3!)

Now I'm a bit worried as I'm almost out of fuses, and no clue what the gently caress is going on. I check the terminals on both end and ensure there's no shorts or anything. Everything looks fine. Fan works fine on manual mode. Furnace kicks on and heats just fine. So it has to be the AC unit outside.

I tested it by removing the wire leading to the AC unit from the Y terminal, and power it back on. Set it to cool, the fan kicks on, everything is fine! Making progress here, right?

So I go outside to check the AC unit and this is what I find:



Yeah, that's the wire, someone stripped off the external insulation, and then apparently wrapped it with electrical tape where it was severed. Repeatedly. Overzealous landscaper is my guess, but what a lovely fix.

I ran a fresh length of cable to the unit and spliced it in as best I could, heatshrink tubing around the splices and then gave it a good covering of electrical tape. Think that will be enough? I'm not eager to rip open the unit if I can avoid it.

Do you think it's safe to put the Add-a-wire and the fancy Tstat back in?

Also, I should probably replace that insulation on the coolant tube, right? Is that something any jackass who isn't afraid to tinker with poo poo (like me) can do?

ExplodingSims
Aug 17, 2010

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




I don't really get what the add-a-wire kit does, but if it was working fine before you should be fine to set it back up.
Unless you wanna do it properly and run a new 5 wire cable down to the tstat.

As for the suction line insulation. You can replace it, they sell Armaflex at Homedepot, or you can buy it online.
Make sure you get Armaflex, not the lovely water pipe stuff though, and just split it open, slide it over the line, and glue it back up.

MRC48B
Apr 2, 2012



If you're going to go through the effort of running a cable, run an eight conductor cable. You or someone else in the future will thank you.

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

Seconding the above. That wire is the clear cause of the issue, not the add-a-wire and thermostat; but if you're able to run a new 8 conductor cable all the way from the unit to the tstat, do so.

ExplodingSims
Aug 17, 2010

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




You know what's really fun? Working on stuff all day then coming home to find your own A/C not running.
The cause? Cap died.



For reference, caps are supposed to be flat on the top. Not bulging out.

Nerobro
Nov 4, 2005

Rider now with 100% more titanium!


My AC wasn't working when I started it up this year. The system is new, as of three years ago. (I'll look up the brand..)

I had my HVAC contractor come out, he refilled the system, and it's cooling now, but he believes that the problem is the evaporator coil, and that the evaporator has sprung a leak.

Seriously, three years?

So, what leads to early evaporator death. What's the typical manufacturer warranty on parts like that? (is there one?) What should I do to prevent it from happening again? And should I have the whole system leak tested?

Thanks.

ExplodingSims
Aug 17, 2010

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




If you have a halfway decent contractor he should do a leak test before refilling.
Either electronic, with soap bubbles, or the best way, pumping the system up with nitrogen.

Warranty depends on the brand, but most have at least a 5 year parts warranty.
As far as prevention goes, there's not much you can do, if you have a leak in the evap it's either from a corrosion issue, or lovely manufacturing.
Of course, this is why you do leak searching, so you can pinpoint the leak. If it's actually IN the coil, then replacement is necessary. If it's on one of the end bends, or other joints then that can be fixed.

Speaking of evaporators, here a fun unit I got to service the other night.


A 36 ton split system. Each one of the RTU looking things are evaporators.
It's driven by 2 hugeass compressors, like the one's in supermarkets. It was pretty cool.

ExplodingSims fucked around with this message at 01:25 on May 26, 2016

Chillbro Baggins
Oct 8, 2004
Bad Angus! Bad!


ExplodingSims posted:

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.
Maybe it depends on the chain, the ones I've seen (even in new builds) aren't attached to the ceiling and have what appears to be pretty beefy lumber around the edges inside the panels. They store extra shelves and poo poo on top of 'em, so they can't be that flimsy.

Either way, it's gotta be better than being out on the sales floor in a vast open space (once the roof gets ripped off) full of small glass objects in a tornado.

ExplodingSims posted:

In other news, I went through my phone and found some pics I've been meaning to share.

Why size the evap correctly for the space you're cooling when you can just do this?


I've seen some just-over-100-square-foot computer rooms in stores with the single-fan version of that. Presumably built back when the computers were much less efficient, and now they're always uncomfortably cold. OTOH, in the newer builds that just use the regular A/C to cool the computer room, they're uncomfortably hot.

iForge
Oct 28, 2010

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

Ive been working at secure sites a lot lately. Can't have a phone in those datacenters, so I can't take pics of the stuff I find. Prepped a motor to come off a chiller today. 4160v ~800hp motor was smoking over the weekend so they shut it down. They had a company come out and test it in place, but we all knew it would have to come down. It is grounded and needs to be rewound, and the customer wants to buy spare motor from us just incase this happens to one of their 5 other identical chillers. The new motor is probably $70,000, and the rewind is probably $30,000. Add in labor, and this breakdown is costing them (ballpark) north of $110,000. Business is good.

slap me silly
Nov 1, 2009


Grimey Drawer

iForge posted:

$70,000 $30,000 $110,000
Jesus

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MRC48B
Apr 2, 2012



Advantages of HVAC: You can get in snowball fights in June.



Not shown: the two inches of snow on the evaporator. Didn't think to get a picture before I defrosted it.

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