|
Want to say a big thanks to this thread, and MRC48B in particular, for helping me with my furnace wiring project. I just strung the 18/5 cable and wired up the relay to the furnace today. Got a functional common wire and the furnace turns on. Even better, the google nest works so my wife is happy. I’m pretty happy with how the wiring turned out. I had a spare junction box to contain the relay wiring. It’s a little cramped, but it’s ok with 18 gauge wire. Unfortunately the box cover didn’t fit with both screws (it’s like 1/8” off), so I’ll need to fix that later. Think about this some more, I didn’t have a grounding wire, so that box isn’t grounded. It’s only a 24 Vac circuit, but it could float semi-arbitrarily from ground if it touches the circuit components. I think I need to ground the box. Ok, what’s the right way to do that? I could run a wire to a nearby receptacle and ground to the house circuit ground wire. That’s a different breaker than the furnace, but it should be the same ground wire. Or I could walk back to the furnace and ground there. Grounding to a pipe feels like the wrong answer. I could also buy a plastic box and swap it out, but that will take time. 
|
#
?
Jun 4, 2021 21:32
|
|
|
|
| # ? Jun 6, 2024 01:25 |
|
|
C wire = Common which should be grounded. If you're using wire nuts properly there should be zero chance of a live box, unless your house has a vibration issue. If you're that worried about it (Don't, it's low voltage, there is no grounding requirement, and any potential +24 will have over current protection), add another wire to the C wire nut and screw it to the box.
|
|
#
?
Jun 4, 2021 21:58
|
|
|
MRC48B posted:C wire = Common which should be grounded. I get a little confused by AC circuits, particularly across a transformer. I’m a battery scientist, so I spend more time in DC electrical systems. I believe you, but I’ll need to draw out the transformer circuit and convince myself of the relationship between the common wire and ground. But 24 volts is touch safe, so there isn’t an issue so long as common is near ground. My only worry would be if the voltage became unrelated to local ground. This might not be a thing in well-built AC systems, but my mind jumps there because batteries can float away from ground and get to some surprising voltages.
|
|
#
?
Jun 4, 2021 23:50
|
|
|
Pittsburgh Fentanyl Cloud posted:Don't do mini-splits, I just had central air added to a 114 year old house with ducting added in the 1950s and it works just fine. Just had a 16 SEER condenser unit thrown outside and an evaporator coil thrown into the Trane XR95 furnace and everything works pretty good. This is piquing my interest. What's the layout of your home? I'm in a 125 year old house with similar-vintage ducting and a Trane XR90. It all works very well for heat. I want to ditch the Window A/Cs in the summer. The catch is that it is a three-story, two-family house. My living unit is the 2nd and 3rd floors. The 3rd floor needs the most cooling as it both gets the hottest and I spend the most time up there (bedroom, WFH office). The 1st floor unit had conventional A/C installed a couple years back and it works fine. But I've heard some "don't do it" about conventional and pushing cold air up three stories. Got one quick quote for an HVAC install and it was like $37K and I'm also not convinced it's actually the best solution. Mini-splits seem rather big on the wall and I don't need the heat functionality at all. admiraldennis fucked around with this message at 00:23 on Jun 5, 2021 |
|
#
?
Jun 5, 2021 00:20
|
|
|
admiraldennis posted:This is piquing my interest. How big is your home? Do you have attic space? My house has a retro'd unit in the attic because the regular furnace+AC just can't provide enough cooling on the second floor. It's got it's own set of vents and returns. (and this is a house of half the age you're talking about)
|
|
#
?
Jun 5, 2021 00:24
|
|
|
Motronic posted:Do you have attic space? That's a good question. There is no attic door or other access to the attic space. But the flat 3rd floor ceilings + tall gable/hip roof above it certainly implies attic space. admiraldennis fucked around with this message at 00:35 on Jun 5, 2021 |
|
#
?
Jun 5, 2021 00:31
|
|
|
admiraldennis posted:This is piquing my interest. What's the layout of your home? Mine’s a three story foursquare, 24x30’, only the first two floors and the basement.are ducted. The third floor is finished but it isn’t really used as anything but storage. The hvac guy outright told me that pushing it up three stories is impossible.
|
|
#
?
Jun 5, 2021 00:38
|
|
|
admiraldennis posted:That's a good question. There is no attic door or other access to the attic space. But the flat 3rd floor ceilings + tall gable/hip roof above it certainly implies attic space. Might be able to expose that/add access/see what's up there. It may be worth a shot. Just so you know, most of those attic systems are physically sized so that you can pull the unit up through the hole you cut as a return. They're kinda long, so you need some height to make the turn pulling them through there, but any decent HVAC company should be able to give you a guess at if it might work before you go tearing into drywall/plater and lathe.
|
|
#
?
Jun 5, 2021 01:33
|
|
|
Condenser unit for the downstairs heat pump has recently (the past few days) started squealing for just a second or two when the cooling temperature reaches the set point and the whole unit stops. How bad is this likely to be? I think it's the older condenser so I'm not sure how old it actually is.
|
|
#
?
Jun 7, 2021 03:47
|
|
|
weird noises aren't really something we can diagnose by forum post. maybe the condenser fan bearing.
|
|
#
?
Jun 7, 2021 04:20
|
|
|
MRC48B posted:weird noises aren't really something we can diagnose by forum post. maybe the condenser fan bearing. Ok, thanks! I wasn't sure if this was a long shot question or not. It sounds a little squeaky spinning up, just not quite so bad, so that's maybe a good guess.
|
|
#
?
Jun 7, 2021 04:30
|
|
|
Is the motor connected to the fan with a belt? Could be a belt just needs to be replaced.
|
|
#
?
Jun 7, 2021 04:35
|
|
|
SpartanIvy posted:Is the motor connected to the fan with a belt? Could be a belt just needs to be replaced. No, motor is attached to the top grate. Thanks though.
|
|
#
?
Jun 8, 2021 00:38
|
|
|
The owner of my condo rental cheaped out on a number of things and 1 was mounting the HVAC unit. It's in its own closet sorta half-exterior to the unit, but it's mounted on a cheap piece of plywood and the noise and vibration from it are unimaginably loud. Through the wall in the next room over, it's like a plane taking off (and I've lived near an airport). It wreaks havoc on my voice/video chats. I've got my half-year inspection from the management company coming through next week. Is this something I can push them on? Are there simple solutions? If I can't get them to budge, can I make a dent in this myself?
|
|
#
?
Jun 10, 2021 16:44
|
|
|
I have mystery water coming from my attic a/c. Turned it off last night, went up there this afternoon. Its 110F up there, you know. The condensate drain line is not cracked (it has frozen and cracked before, I was hoping this was the problem). Water is successfully draining to outdoors, fills a pickle jar in under 15 minutes. Everything in the attic is dry to the touch, now. The insulation on the line-set is in poor shape and the copper pipe has a visible glisten. Could it have condensed so much water that it soaked through the fiberglass insulation, then through the drywall? OR MAYBE The condensate line is slightly blocked allowing it to collect and overfill? Seems unlikely? Or maybe something else?
|
|
#
?
Jun 11, 2021 23:03
|
|
|
Both of those are possible options. Recommend you fix both, as Its not me who has to go up there.
|
|
#
?
Jun 11, 2021 23:19
|
|
|
Urgh. Seems like a lot of physical pain without knowing the source of the moisture. There isn't some old timer trick to tracking this down?
|
|
#
?
Jun 12, 2021 01:38
|
|
|
horse_ebookmarklet posted:Urgh. Seems like a lot of physical pain without knowing the source of the moisture. Yeah putting something very absorbent under it and changing their business name. If you're filling a pickle jar with water in 15 minutes then you should start by completely cleaning your condensate system. It's the obvious source of bulk water. They make tablets I think that you can put in the tray that will help kill the slime. If you can get a air line up there you can probably also blow out the line. That should limit your exposure to the hell world in your attic. Stick a cup under the likely drip point for the pipes. If it overflows there is your problem.
|
|
#
?
Jun 12, 2021 02:29
|
|
|
it is incredibly unlikely you're line set is condensating that much, it's possible if you're low on refrigerant, meaning you have a leak, that your suction line could be freezing, if you're worried about your condensate lines getting clogged consistently you either have inadequate filtration or your indoor evaporative coil is dirty/impacted or is rusting out
|
|
#
?
Jun 12, 2021 06:56
|
|
|
Tablets are an easy cheap call, I'll try that. Slime, gross. The last time the condensate line froze I put an air fitting and a ball valve (yes it is open) in line as close to the unit as I could, so I can blow it out. Last fall it doesn't sound like there is any pressure able to build up. But this doesn't cover the short 6 inches of pipe into the unit, or anything inside the unit... The coil could be dirty, and it could be rusty. The system was installed in '98 or '99. The ozone takes about a half pound of R22 for the team every-other spring, just topped it up. Also replaced filters at the same time. Been running again for a day and a half, no moisture. There has been less A/C demand as the heatwave passed. I'm going to put printer paper under the possible sources, hopefully it'll indicate where the drip comes from. That or provide bedding for mice.
|
|
#
?
Jun 13, 2021 02:30
|
|
|
you need a new air conditioner
|
|
#
?
Jun 13, 2021 02:41
|
|
|
horse_ebookmarklet posted:The system was installed in '98 or '99. The ozone takes about a half pound of R22 for the team every-other spring Ace of Baes posted:you need a new air conditioner
|
|
#
?
Jun 13, 2021 02:45
|
|
|
My first time repairing the condensate line I was barely a teenager, mid 30s now. I mean, yea the cabin needs a new AC, but also a ton of other repairs. $200 every other year is so cheap, especially for infrequent use. And the ozone hole is shrinking! Maybe not as fast as it could. Previous A/C out calls I've made to difference service companies, nobody installs attic units anymore. Minisplits seem ugly. This is my grandpappy's A/C. I need to keep it running to honor his memory.
|
|
#
?
Jun 13, 2021 03:32
|
|
|
The last service guy out here was probably 300 pounds. Said if he had to go up in the attic and crawl through the rafter webbing, he would have to call the fire department to cut him out. Wonder why nobody installs these in attics anymore
|
|
#
?
Jun 13, 2021 03:36
|
|
|
I was about to ask what the hell you were talking about with the "nobody installs in attics anymore" because....yeah, that's not at all true and you need a new HVAC company.
|
|
#
?
Jun 13, 2021 03:38
|
|
|
I had a similar issue with a 300 lb HVAC guy and went with a different company. How you make it as a contractor without being able to fit through anything less than a 36" door boggles my mind.
|
|
#
?
Jun 13, 2021 03:44
|
|
|
300lb Mason? Fine. Not repointing a crawl space but there is plenty of bricklaying to be done in the open. 300lb hvac/electrician/plumber? That's the wrong profession to let your diabetes get that uncontrolled in. You wouldn't be wrong to send them on their way without paying for the call out if they refused to get into your otherwise normal attic. That's the opposite of showing up "ready to work".
|
|
#
?
Jun 13, 2021 04:11
|
|
|
horizontal attic heat pump/gas splits are one of the most popular residential air conditioning set ups there are, if you're going to insist on keeping your piece of poo poo r22 clunker at least hire someone with half a brain to run a dye kit through it and identify where it's leaking and repair it
|
|
#
?
Jun 13, 2021 04:46
|
|
|
horse_ebookmarklet posted:And the ozone hole is shrinking! Maybe not as fast as it could. Thats not how this works. R22 is over a thousand times worse than C02 by weight for global warming.
|
|
#
?
Jun 13, 2021 04:53
|
|
|
I didn't see a question formatting post so let me know if you need any additional information to help me out with this question. Also I know due to labor shortages etc this will either take more time or more money than it would normally. I'm really just trying to get a feel for what is feasible/reasonable to do for my place. I own a condo in a 16 unit, four story building (no units on the ground floor though). I am on a high first. The building does not have central air so I have window AC units during the summer (it's only hot enough here that I need them from June to mid-Septemberish). These work alright but 1) they are loud and 2) it is definitely still pretty warm even with them on. I would like to get something better to help cool it but I don't really know what options are available between the end points of "window AC units" and "full on AC system." What are some things I might look into?
|
|
#
?
Jun 13, 2021 17:09
|
|
|
You probably want a mini split system.
|
|
#
?
Jun 13, 2021 17:18
|
|
|
Badger of Basra posted:I didn't see a question formatting post so let me know if you need any additional information to help me out with this question. Also I know due to labor shortages etc this will either take more time or more money than it would normally. I'm really just trying to get a feel for what is feasible/reasonable to do for my place. I'm assuming you meant "high floor" and not "high first"? You're going to be dealing with a bunch of heat rising from the other floors, so you'd probably need to oversize window units for the space they're in. Any sort of upgrade here is really going to require the ability to mount equipment on either the roof or outside of the building (the waste heat has to go somewhere!). Is your condo going to let you do that? That's going to be the first question before you even talk to any HVAC companies. These are essentially a mini-split in a window form factor - they are no louder then a regular floor fan. Depending on how many rooms you have, it'll likely be cheaper to buy a few and use them for a few years, and then consider getting something bigger installed. HVAC prices are likely hosed right now because on top of COVID, the summer heat has just begun. Now is a bad time to be starting this project.
|
|
#
?
Jun 14, 2021 00:56
|
|
|
devicenull posted:I'm assuming you meant "high floor" and not "high first"? You're going to be dealing with a bunch of heat rising from the other floors, so you'd probably need to oversize window units for the space they're in. I can personally stand behind the window unit referenced in this post. Extremely efficient, quiet, and powerful. If you don't mind it taking up some of your window, it's absolutely as good at AC as a proper mini split, though it doesn't have a reversing valve to work as a heat pump in the winter. But if you're happy with your building heating arrangement that shouldn't be an issue.
|
|
#
?
Jun 14, 2021 01:40
|
|
|
I work in a restaurant and we have a classic problem – dining room stays a little too cold, has tons of airflow, kitchen feels like it has no airflow at all. Landlord is claiming that there's no underlying issue and the system is running as well as any other, but I can't really believe that and I'm trying to understand what's happening. The HVAC system appears to be a Trane Voyager, set up as changeover bypass. Air returns are through the plenum. There are only two zones, the dining room and the kitchen. Dining room unit is a Varitrane F, whose setpoints directly measure air flow (cubic ft/min,) and the kitchen unit is a Varitrac which only sets airflow in damper position %. I'm specifically wondering about these diagnostic codes. (imgur album here)   I'm guessing the calibration failure may be connected to our airflow problem? In another screen, the static pressure reading seems to be 0, and if the bypass position is 0% (fully shut?) then it seems like the system is doing everything it can, but isn't operating properly. From what I've read, keeping a static pressure setpoint is essential to regulating airflow, so what we're getting is at the very least not normal, right? 
|
|
#
?
Jun 14, 2021 02:58
|
|
|
The compressor lockout is the bigger problem. You aren't getting cooling in that state. You need a HVAC technician to fix the system.
|
|
#
?
Jun 14, 2021 03:20
|
|
|
Thanks! That is good to hear. Any idea why we can still get cooled air in the dining room? Do commercial spaces have second units often?
|
|
#
?
Jun 14, 2021 03:35
|
|
|
It likely has multiple stages of cooling. Your landlord is being a cheap poo poo.
|
|
#
?
Jun 14, 2021 04:04
|
|
|
Thanks folks  we'll keep pushing on the landlord then.
|
|
#
?
Jun 14, 2021 04:22
|
|
|
handle posted:Thanks folks Tell them one of their compressors is showing a lockout fault. "I asked an hvac friend of mine what that meant and he rambled on then realized it was over my head and said it means it's refusing to turn on because it's broken." The first thing they will do is mash that reset button but it's highly unlikely to do anything beyond make it try to start 4 more times and lock itself back out, but so be it.
|
|
#
?
Jun 14, 2021 04:34
|
|
|
|
| # ? Jun 6, 2024 01:25 |
|
|
My guess from the many HVAC YouTubers I've watched is that the high or low pressure sensor is broken, or the radiator fins are clogged with grease
|
|
#
?
Jun 14, 2021 04:39
|
|