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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. 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?
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Jan 24, 2016 13:07
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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 01:38 on Jan 30, 2016 |
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Jan 30, 2016 01:34
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Most of your images won't load for me 
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Feb 7, 2016 07:57
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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 
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Feb 7, 2016 23:46
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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.
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Apr 12, 2016 06:11
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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.
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Apr 12, 2016 06:44
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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.
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Apr 13, 2016 08:37
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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/nest-thermostat-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)
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Apr 14, 2016 00:28
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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
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Apr 15, 2016 00:16
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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.
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Apr 27, 2016 01:18
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Yup. System might just be undersized, too.
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Jul 18, 2016 01:44
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chedemefedeme posted:It's a private office with only 3 desks, one door to the outside world, and no windows. It's literally a 900sqft wood and sheetrock (w/ fiberglass insulation) office built inside of a 24ft high warehouse space, the remaining 2000sqft of which is the high ceiling warehouse. The "outside" unit is on the true roof, not inside the warehouse. Zhentar posted:The hot has to come from somewhere. If it's not from outside, and it's not from the sun, then where? What sort of climate control setup does the warehouse have, if any?
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Jul 18, 2016 08:50
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Not quite true, the computers etc will generate a small amount of heat, but it definitely shouldn't be enough for a duty cycle like that. I'd be checking the coils on the inside unit and making sure they're clean (buy a can of coil cleaner if not), and then getting an AC tech to check if it's low on refrigerant amongst other things. The way to prevent yourself getting hosed over is pretty simple, also - just don't let them talk you into anything expensive without a 2nd opinion.
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Jul 20, 2016 04:12
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ExplodingSims posted:How many wires do yo have, and what terminals are they landed on? This. Also, a photo of the wires where they connect into the AC unit itself would be useful (so we can see the unit's labels for things) Chances are that black wire needs to be hooked up to the C terminal, if you have nothing hooked up there. Black wire marked "E" sounds like "Earth" to me aka C/common.
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Jul 27, 2016 05:28
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kmcormick9 posted:
If switching the thermostat back didn't fix it then chances are it's not the thermostat's fault, pressure switches notwithstanding I can't confirm without a pic of the wires at the other end, but I'd wager that black wire needs to be hooked up to the C terminal on the Nest. That, or you need an add-a-wire kit since you don't have a C wire and you really need one for a Nest to work properly. literally a fish fucked around with this message at 02:23 on Jul 28, 2016 |
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Jul 28, 2016 02:21
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Qwijib0 posted:E is usually Emergency Heat, which the nest seems to have detected properly. I'll take your word for it as I am by no means an expert. AFAIK just a few pages ago we had a big long discussion where everyone concluded that Nests need a C to work properly even though they claim they don't (as their parasite-power function can confuse and disorient many HVAC units) so perhaps an add-a-wire kit is necessary. Before spending money though it's probably also a good idea to hook the old thermostat back up just to make sure everything still works (without pressure switches getting in the way) and that nothing's blown up
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Jul 28, 2016 06:15
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LV transformer failure?
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Sep 29, 2016 15:17
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Try to get as close to 35VA (existing rating) as possible, too. And yes, do check that you were checking white/black and white/red, not red/black and white/white
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Sep 30, 2016 14:57
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borkencode posted:Yeah I was checking black/white, and red/light blue. Yup, transformer's dead. Any 30-45VA 24V transformer ought to work (1.5A-2A or so)
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Oct 1, 2016 06:03
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