|
Just had sort of a shower thought and I figured I'd toss it out there and see how stupid it might be. Could one run the hot line of an A/C system through a cold water pipe and gain extra cooling efficiency when the water is flowing? Since the indoor part of a central air system tends to be colocated with the water heater I was thinking one could put such a system on the input side of the heater, thus using waste heat from the AC to reduce the water heater load and also eliminating the problem of surprising someone with hot water where they want/need cold if you connected it up anywhere else in the system. My A/C tends to kick on while showering or running the dishwasher for obvious reasons and I was thinking if it did something like this it might be more effective at cooling the house while simultaneously extending the time before I run out of hot water by warming the input. Of course this is purely hypothetical as well, I'm not about to go trying to re-engineer my home's water and cooling systems any time soon.
|
#
¿
Aug 16, 2016 18:36
|
|
|
|
| # ¿ Apr 29, 2024 20:16 |
|
|
Does EcoBee actually require the fifth wire to work? Nest recommends it but generally works fine on a standard 3/4 wire system. It connects a small amount of power through that's not enough to trigger the system in most cases but is enough to charge.
|
|
#
¿
Dec 7, 2016 20:23
|
|
|
devicenull posted:Yes, it does. Well then, good and moderately annoying to know. I was considering switching over to one because I hear they're easier to integrate with homebrew scripts and such, but I only have four wires.
|
|
#
¿
Dec 8, 2016 06:41
|
|
|
That's a decent solution.
|
|
#
¿
Dec 9, 2016 05:20
|
|
|
So to be clear, you only have two wires coming in to the thermostat, W and R? (Rh and Rc being bridged is normal and it's just called R in that case) As noted in the above post about the Ecobee, a standard household thermostat is just basically an automatic switch that puts power on different wires to activate the various systems. R is the 24vAC supply. W is the signal line that requests heat. Connecting R to W tells the heater that you want it to do its thing, and it's going to stay on until that connection is broken. Without a C line Nest devices can sometimes run a small amount of power through the available connections to charge their batteries if they're not kicking on enough to leech power normally, this can cause components to kick on unexpectedly but there's no way for it to cause the heat to run slower. If you also had a G line I could see the potential for weirdness if the way the fan was operated was different between thermostats, but with a two-wire heat-only system you should be able to just literally twist the wires together and the heat will kick on normally. Everything else is under the control of the heater itself.
|
|
#
¿
Nov 28, 2017 20:38
|
|
|
You could always bypass the thermostat altogether and just connect R to W directly for a few minutes and see how things feel. That's all a dumb mechanical thermostat would be doing.
|
|
#
¿
Nov 28, 2017 21:53
|
|
|
If by four-wire you mean RGWY then that fits pretty well with the HVAC system not being friendly to Nest's power trickery and adding a C wire if possible should solve the problem, otherwise you'll need something not Nest. If it's RWYC then that probably just means the Nest itself is broken.
|
|
#
¿
Nov 29, 2017 15:29
|
|
|
Crotch Fruit posted:I find the appearance of the Ecobee displeasing and I think the Nest just seems to have more features I want like automatically learning my schedule. Is there a difference between the cheap and expensive Nest? What other options should I consider for something that looks good, has auto change over between heat and cool, easy to program, and has wifi that plays nice with Google Home? My current thermostat (Honeywell TH8320U) has R, W Y G and C wires and a jumper from Rc to R. Aside from the obvious display and physical construction differences, the cheap Nest doesn't support multi-stage heating/cooling or humidifier/dehumidifier control. This won't matter for you or most people with standard forced air systems.
|
|
#
¿
Dec 11, 2017 22:04
|
|
|
nine16thsdago posted:thank you! I have read somewhere that trane/AS use "B" as "common," and in the trane installers manual (edit: i.e., the one for my model number), that seems to be indicated in the wiring diagram. so moving the wires on my current thermostat to the ecobee, i'll map the following: https://nest.com/support/article/Should-my-B-wire-go-in-Nest-s-O-B-connector-Or-is-it-a-common-wire-that-belongs-in-the-C-connector
|
|
#
¿
Dec 16, 2017 05:52
|
|
|
Bad Munki posted:I’d like to hook it up to a thermostat like the Honeywell I have in my house, which I can control from my phone. Problem is, the unit has its own built in controller. Would it be reasonably viable to bypass the built in stat and use a standalone unit instead? Would I likely be able to use the 2-stage design of the unit for better efficiency? When I converted a freezer in to a kegerator I just set the built in thermostat to the coldest position. When the external thermostat gives it power the internal thermostat immediately kicks it on. Seems like the same idea could work just fine in the opposite direction, set the built in thermostat to some cutoff temp above where you'll ever want to actually set it to. That also would provide a safety factor if your automation system fails which you'd lose if you bypassed it.
|
|
#
¿
Feb 4, 2018 00:21
|
|
|
How big of a deal is two-speed operation? My girlfriend's brother and sister-in-law just moved in to a new place that has a two speed Carrier HVAC system but only a classic round Honeywell thermostat. Would upgrading to a fancier thermostat that can take advantage of that be worthwhile? It's probably only wired for four conductors at this point but there's easy wiring access from the basement so it wouldn't be more than an hour or so to run a new line. Also if we were to do that, would ethernet cable be acceptable or would we be better off getting something thicker? Obviously the colors wouldn't match but I have a sheet of those flag stickers that come with a Nest.
|
|
#
¿
Dec 31, 2018 20:42
|
|
|
devicenull posted:Furnaces can usually be set to handle two speed operation by themselves (run at a slower speed for awhile, then kick up to high speed if there's still demand). Changing it probably wouldn't do a lot for you. I skimmed the manual the other day and kinda got this idea from it, but wasn't entirely clear. Probably not worth the effort then.
|
|
#
¿
Jan 2, 2019 05:56
|
|
|
Gotcha, yeah I wasn't sure what the current levels would be, just knew 24v AC.
|
|
#
¿
Jan 2, 2019 16:14
|
|
|
Motronic posted:It depends. You should just be energizing contactors on the unit(s), but some of those contactors can have quite a draw and can be pretty far away in cable feet (like the contactor for the outdoor compressor). That's pretty much what I was figuring based on STR's response, that it probably would work fine in some cases but there's a chance it'd be overheating the wire and without actually measuring this specific unit we'd always be risking failure. With devicenull's comments about the unit probably handling speed changes automatically agreeing with what I read in the manual we're probably not going to bother changing anything at the moment, but if they ever want to do a Nest or other fancy thermostat we'll get some proper wire to be safe. The idea of using ethernet cable was pretty much just a "well, I have a spool in my trunk pretty much always, so we could do it basically for free next time I'm over" type thing. Also as a random aside, I found out that Belden actually makes an 18ga ethernet cable for industrial applications. Cat5e certified and enormous. 
|
|
#
¿
Jan 2, 2019 18:16
|
|
|
Pollyanna posted:How can I find the biggest source of heat loss in the apartment? I hear windows are the biggest offenders, and there’s some bubble wrap or something you can apply, but is there something else I can do too? Keep in mind that I can’t just replace the hilariously old heating system, cuz I’m not the landlord and I’ll be hosed if I sink any more money into this slum. Low hanging fruit that you can do something about for relatively cheap will probably be door and window seals, sometimes outlets on exterior walls.
|
|
#
¿
Jan 29, 2019 17:27
|
|
|
H110Hawk posted:In theory UV is the thing that kills bacteria without secondary effects but you have to change the bulbs regularly (annually?) Obviously that'd still be fine for installation inside a duct but people should definitely not get the idea that they could install UV lamps around their house to keep things cleaner.
|
|
#
¿
Aug 4, 2020 20:17
|
|
|
Pollyanna posted:How do old-style thermostats work? If you don't know how a thermostat controls a central heat/air system in general that part is at 2:31. The part specifically about basic analog thermostats starts at 4:41.
|
|
#
¿
Oct 19, 2020 16:17
|
|
|
kastein posted:That's pretty cool, I had no idea bacnet existed. I wonder why it's not bigger in resi hardware, maybe perceived cost? There's no technical reason Nest couldn't have a local REST API on the thermostat itself, it's just a Linux computer with a few GPIOs connected to SSRs, but that doesn't benefit Google and the majority of buyers don't give the slightest bit of a gently caress. And of course don't even get me started on the average non-technical consumer's belief that wireless everything is a great idea.
|
|
#
¿
Dec 9, 2020 16:43
|
|
|
H110Hawk posted:I am a mature adult who is a professional. Also, technical people can be some of the worst when it comes to thinking wireless-everything is a great idea. On the other part I think we need to be careful to divide gadget people from technical people. Both tend to like to have tech in their homes, but the choices made and reasons for those choices tend to differ significantly. Of course it's not black and white, there's plenty of overlap in this venn diagram, but at least in my experience those who actually understand at least the basics of how wired and wireless communications work tend to prefer wires where practical. Those who see it as more or less magic tend to be the ones who want wireless everything even when it doesn't make sense. corgski posted:I keep hoping someone will release a root and custom firmware for the Nest that does this so I could at least make mine somewhat useful. Annoyingly some of the earlier models even had a ZigBee radio but it was never used. edit: I just had a horrifying thought of someone trying to implement communication to dampers and such using the HVAC ducting itself as the medium for something like a one-wire protocol. edit2: Did a bit of searching around to see if anyone had done further work on jailbreaking, the answer seems to be a hard no, but it was pointed out on the original jailbreak that at some point Nest dropped a package that will supposedly build you a complete bootable firmware for one of the first two generation models, minus the Google proprietary software (the GUI and control software) but it doesn't look like anything's really come from that either. http://opensource.nest.com/NestLearningThermostat/4.x%20Opensource/nestlabs-open-source.tgz https://nest-open-source.googlesource.com/ wolrah fucked around with this message at 20:14 on Dec 9, 2020 |
|
#
¿
Dec 9, 2020 19:49
|
|
|
MRC48B posted:there are a few commercial "heat recovery' chillers that can heat water to 180f on one side and chill to 45f on the other.  So you're saying a machine exists that could sous vide my dinner while chilling my beer with the same electricity?quote:they are expensive and uncommon. 
|
|
#
¿
Mar 5, 2021 16:00
|
|
|
MRC48B posted:If you're just using it as a glorified IOT thermostat on the RGYWBO, knock yourself out. Hell, even for that when I was contemplating DIYing a thermostat I was still designing it with relay-based interlocking so it couldn't physically call for hot and cold at the same time and a connection to an external mechanical thermostat that would disconnect the Arduino until manually reset if it was triggered to ensure the pipes couldn't freeze if it stopped working. Obviously not entirely necessary, but when my homebrew code on a cheap device would have the potential to cause thousands of dollars in damage if it went wrong while I wasn't home I wanted fail-safes. I ended up not doing it because my landlord was already sketchy about my Nest after the heater failed (four years later, and due to the flame tubes rusting out rather than anything a thermostat could cause) but still. wolrah fucked around with this message at 21:49 on Apr 16, 2021 |
|
#
¿
Apr 16, 2021 21:44
|
|
|
IOwnCalculus posted:AZ here, I've never seen an air handler for a heat pump installed in a conditioned space. Most (including both houses I've owned) have the air handler in the attic and the outside unit mounted on the ground. My mom's house is the only oddball I've been up close and personal with, but even then one air handler is in the garage and the other is in an exterior-opening closet by itself. The only time I've ever seen an air handler outside of the conditioned space in a single-family home was my grandparents' house outside of Las Vegas, but that was more or less a commercial barn with a living space rather than a normal home.
|
|
#
¿
Jun 29, 2021 17:18
|
|
|
Motronic posted:Most gas air handlers are not freeze safe anymore, because even the lowest efficiency units will produce condensate while heating. AC only units, or heat pump only heat/AC are mostly fine to be in unconditioned spaces even where it freezes. The regional differences in the way we build our houses are always neat to learn about.
|
|
#
¿
Jun 29, 2021 21:06
|
|
|
IMO it should just be considered a hard rule, if you can reasonably run a wire you should run the wire. Wireless is for things that need to move around and things that need to be installed in locations where running a wire isn't worth the effort.
|
|
#
¿
Oct 20, 2021 16:23
|
|
|
Relevant Technology Connections video: https://www.youtube.com/watch?v=V-jmSjy2ArM The tl;dw version is simply that for resistive heaters, wattage is all that matters. The amount of power they take in is the amount of heat they put out.
|
|
#
¿
Aug 16, 2022 20:06
|
|
|
|
| # ¿ Apr 29, 2024 20:16 |
|
|
If anyone has a Rheem with their cloud connected features, you might want to pay attention: https://twitter.com/klinquist/status/1593996134103453696 MQTT is a message queueing protocol, kinda sorta IRC for gadget control traffic and data reports, used in a lot of connected devices. At the moment it seems like it's just a data leak, but even if so it's a strong indicator of the system not being well designed from a security/privacy standpoint. wolrah fucked around with this message at 18:10 on Nov 19, 2022 |
|
#
¿
Nov 19, 2022 18:07
|
|