7 ms·

This is when smart gets stupid. I'm a bit worried about this with my nest and other smart devices, but even with normal air conditioners there are a few stupid

by cbanek 2y ago

This is when smart gets stupid. I'm a bit worried about this with my nest and other smart devices, but even with normal air conditioners there are a few stupid simple problems that will cost you hundreds of dollars! A couple of weeks ago my AC blower fan stopped working, the compressor would run. I went up and found out that the capacitor was bad, and took a picture of it, buying a replacement. Took about 15 minutes to replace and I probably saved myself at least $400 (no AC is an emergency in the desert, and they will charge you accordingly). Fixing household appliances can be fun too!

asah 2y ago
+1. Repair all sorts of stuff... Capresso burr grinder, little plastic knob broke off inside, repaired with a 10c washer and glue... worked great for years and you'd never know...
SOLAR_FIELDS 2y ago
I highly recommend people who live in hot environments to keep a spare capacitor on hand. Even if you know how to fix it, if the AC dies when your local HVAC supply store is closed (eg not between 7am-7pm Monday through Saturday usually) you’re either stuck paying out the nose to a contractor who has one on hand during emergency hours or you’re sweating it out waiting for the store to open. While they are readily available components that consumers can purchase, they aren’t things that Walmart carries. But HVAC supply shops will sell them to you, you don’t need to be licensed or anything to buy them. You can also just get them on Amazon, likely for cheaper than the HVAC supply shop will sell them to you. It really is an easy repair. Needs a screwdriver and knowledge enough to shut off the electricity to touch the wires. According to code every one of these condenser units outside has a disconnect right there so you don’t even need to turn off the power at the breaker box. Just pull that disconnect, open up your outdoor condenser unit, snap a pic of the specs on the capacitor (it’s the only thing that looks like a soda can) and order one off Amazon and stash it somewhere. It’s a tiny part. It will take like 5 minutes max and save you several hundred bucks and a lot of sweat eventually. FWIW, when ac dies it’s usually in this order of root causes: Float switch: your condensate drain line got clogged because it just does and you need to clear it. You can proactively prevent this by pouring bleach or vinegar down the line periodically (what clogs it is usually some sort of gnarly plant like growth from all the moisture) or if it’s clogged you need to clear it. The hvac guys will charge you 300 bucks to blow pressurized air through the pipe or you can literally just duct tape a wet shop vac to the thing and suck it out yourself. Attachments can be purchased on Amazon for reasonable price. A capacitor issue is the second most common. If it ain’t the float switch almost always it’s the capacitor. You can increase your capacitor longevity and also decrease your electric bill by changing your air filter regularly but also hosing down the outside condenser coils every few months or so. Almost everyone knows about the air filter but few people know about hosing down the coils. This makes a HUGE difference. We are talking like 20-30% of your electric bill in hot climates if you don’t do it. Just take a hose and spray downward on the grates and get all that dust and dead grass from mowing out of there. You won’t hurt the thing. Why does this help? Well, it’s better to think of AC not as adding cool air. There’s no such thing as adding cool air. Only removal of heat. How does heat get removed out of your house? Through that condenser unit. If those grates are clogged up the heat cannot escape and the unit must work harder to do less effective job. So keep those coils clean. Everything else after that is way less common. Yeah compressors do die. Motors die. Refrigerant leaks. Computer components die. Thermostats fail. However it’s very rare that the issue is something other than these two things in comparison. Like probably 80% of all HVAC residential calls are probably the above two things I mentioned.
- biggc 2y ago
  How big can these capacitors be? Does replacing it require any safety precautions besides turning off the power?
  - pxx 2y ago
    the capacitors are connected across the motor windings and are there essentially as a way to shift the phase of the current waveform. note that this is a two-phase power special; you don't need start or run capacitors if you're using 3-phase power (uncommon in North American residential settings, but YMMV worldwide) when power is disconnected they are not charged at all. it's not like the capacitors you might find in a CRT
    - rocqua 2y ago
      So what you are saying is that the capacitors are effectively shorted with the motor coil, and hence they have a drain resistor that has effectively no resistance?
  - deleted 2y ago
    [deleted]
  - SOLAR_FIELDS 2y ago
    The capacitors size themselves are small. They slightly vary but are almost always the size of a medium Red Bull can. They are sized to your unit though so you can’t just buy one without looking at the specs and expect it to work. But the specs are printed on the side of the can and if not can be derived from the specs on the unit itself. As far as their danger there really isn’t any beyond getting shocked from dealing with live wires. Technically they can retain a bit of a charge so I’ve seen recommendations to wait X amount of time before touching them with your bare hands or to discharge it by touching it with an insulated screwdriver to discharge it but the risk is pretty low. Once the power is off (either at the breaker or via the disconnect at the condenser unit, power only goes in one way to those things so if you turn it off in one place there’s no way you’ll get a zap) it’s a soda can with 3 wires going into it. You just disconnect the 3 wires from the old soda can, remove it, replace and connect the new one. Not that much harder than changing a light bulb.
Nursie 2y ago
The great thing about Australia is that that is probably illegal here. We've got some pretty fucked up protectionist rules about what you can and can't do in/to your own home. It's nuts. Now, nobody is actually watching most of the time, so you're usually fine, but it's as stupid as being illegal to replace a tap or existing light fitting. Every so often state governments review the rules and get swamped by trade associations who say the rules are there to prevent people being 'scammed' by untrained 'handymen' and are there for your own protection. This regulatory capture means that legally you need to complete a four year apprenticeship before you're allowed to change a plug! And another one if you want to do any basic water plumbing. I wouldn't be surprised if what the guy did in this blog is strictly speaking illegal - for instance when it comes to data cables, you need to be a qualified electrician with data specialty to install them. You can plug ethernet cables into your computers yourself (wow! such privilege!), but if you install them even by getting some stick-on plastic conduit and passing the cable through that, you're in contravention and could potentially be fined, up to thousands of dollars. For sticking some plastic tubes to the wall in your own house.
- SOLAR_FIELDS 2y ago
  Reminds me how, in USA, it’s the only civilized nation I’ve been to where you must have a prescription to purchase contacts and glasses. Everywhere else I’ve been will just sell you whatever magnification you need at the pharmacy. Obviously there is some acceptable line here, but I think the States handles this decently well enough. In Austin where I live you can get what is called a “homeowners permit” in a lot of cases. Meaning the city will come look at your work and as long as it’s up to code you get a legal permit just like a contractor would get (https://www.austintexas.gov/page/homeowners-permit https://www.austintexas.gov/page/homeowners-permit). You can only do this to your own home so it’s not a shortcut to running a chuck in a truck business without a license.
  - Nursie 2y ago
    Yeah in the UK where I spent most of my life, it seems like you do whatever you want, pretty much. Golden rule - you don't touch gas plumbing. And you don't mess with your circuit breaker board/RCDs etc. I think installing new ring circuits may be off limits. Anything else? Go for it. I fitted a bunch of taps and a toilet, changed single sockets to double+USB sockets, changed light fittings, fixed poorly wired lighting circuits, installed Cat-6 through the walls to a few rooms, all sorts of stuff. And none of it was anyone else's business. You can (should?) get a professional inspection and safety certificate before you sell the house, but that's about it AFAICT. I'd be happy enough with the situation in Austin, so long as the city inspections were cheap or free. I'd be happy enough to do a short course in the basics before getting some sort of permit. Where we are now is nuts. (But at least I can buy a pair of generic reading glasses pretty much wherever here!)
XorNot 2y ago
The nice thing about my Mitsubishi Heavy Industry units is I've got a bunch of MHI-AC-Ctrl[1] modules tucked into them talking to the service interface with Home Assistant. The neat thing is it doesn't just control it, it also makes all the internal sensors and codes available. What I think we really need to do though is make publishing these control standards mandatory under right-to-repair laws - no one should need to be reverse engineering them, you bring a product to market you have to provide the complete spec for it's software interface and data. Do that, and I bet we'd find in a few years every new appliance would support a common serial port standard and come with a code page in the manual for it (ironically the prevalence of Tuya-smart stuff has come very close to making this happen, but they go to absurd lengths to lock you out of the wi-fi microcontrollers). [1] https://github.com/absalom-muc/MHI-AC-Ctrl https://github.com/absalom-muc/MHI-AC-Ctrl
- cbanek 2y ago
  I'd love this, but right now I'd be happy with a team reverse engineering these things and not getting hit with some kind of IP lawsuit from whatever company. I think there's going to be a lot of abandoned-ware IoT stuff, mostly because the company wants to turn the software off because they don't make money from supporting old products. My fitbit wifi scale, which I love and has been doing a great job for the last 10 years has now lost support to pair it with the new fitbit app, thanks Google!
  - XorNot 2y ago
    One problem I've found with a bunch of my own stuff though is microcontroller firmwares. Tons of devices have some type of microcontroller running them, and if the CPU is what goes (which happened on a bunch of Yamaha amps I've dealt with) then it goes right up in the air as to whether sourcing a replacement part is practical because you can't even get a binary blob to shoot onto it.
- girvo 2y ago
  Oh hey, thats neat. I have two MHI split systems in my house! Definitely going to have a play with this, very nice.
refurb 2y ago
I did something similar for a clothes drier. The thing was ancient (mid-80’s) but was fantastic. It was huge and you could dry maybe 3 comforters under an hour. It stopped heating and it turned out there are solenoids that control the natural gas flow. Quick disassembly (back when products were made for easy repair) and swapping out two $8 solenoids from Amazon and I was back in business.
- jamiek88 2y ago
  And doesn’t it feel great? Unironically one of the proudest moments of my life was when I fixed the the belt on our dryer. A $10 rubber belt and YouTube and voila!
- Scoundreller 2y ago
  Gas hot water heaters will often foul the flame detection sensor over time. Simple YouTube video to unscrew the thing, sand off the crud and back in action.
ApolloFortyNine 2y ago
Everyone reading this should find out what capacitor they need and buy one off Amazon, they're all <$20. I've done this repair myself, it takes maybe <15 minutes and is almost impossible to mess up. Even if you were find spending a couple hundred dollars to have someone come out and do it, you'd still go hours at least without AC. Which depending on the time of year can be miserable.
- Scoundreller 2y ago
  > and is almost impossible to mess up Just don’t cook yourself with the remaining good capacitance. Personally, I wonder what could be done to temporarily get the capacitor to “kick” for a few more times to get your home temperature down as you get your replacement. Chill the capacitor?
  - BizarroLand 2y ago
    It depends on the failure mode of the cap. If it has blown its dielectric, then chilling it may cause the plates to separate enough to boost the capacitance, but it is more likely to just be a waste of time. Aside from that, you could strap on other capacitors as long as their voltage is the right value. A daisy chain of 50mf capacitors to shore up the blown capacitance might buy you a day or so of usage. Best bet, if you have an old broken microwave nearby, would be to pull the cap from it and wire it in.
- quickthrowman 2y ago
  Please don’t suggest buying electrical parts off Amazon, that’s criminal negligence. On second thought, please do not give any electrical advice on the internet. Buy it from McMaster Carr or Grainger, please!! If you do this repair yourself, short the contacts of the capacitor (ideally with a correctly sized resistor) to discharge it before handling it so you don’t electrocute yourself. Start caps: https://www.mcmaster.com/products/motor-starter-capacitors/ https://www.mcmaster.com/products/motor-starter-capacitors/ Run caps: https://www.mcmaster.com/products/run-capacitors/ https://www.mcmaster.com/products/run-capacitors/
  - 2y ago

by cbanek 2y ago

asah 2y ago

+1. Repair all sorts of stuff... Capresso burr grinder, little plastic knob broke off inside, repaired with a 10c washer and glue... worked great for years and you'd never know...

SOLAR_FIELDS 2y ago

I highly recommend people who live in hot environments to keep a spare capacitor on hand. Even if you know how to fix it, if the AC dies when your local HVAC supply store is closed (eg not between 7am-7pm Monday through Saturday usually) you’re either stuck paying out the nose to a contractor who has one on hand during emergency hours or you’re sweating it out waiting for the store to open. While they are readily available components that consumers can purchase, they aren’t things that Walmart carries. But HVAC supply shops will sell them to you, you don’t need to be licensed or anything to buy them. You can also just get them on Amazon, likely for cheaper than the HVAC supply shop will sell them to you. It really is an easy repair. Needs a screwdriver and knowledge enough to shut off the electricity to touch the wires. According to code every one of these condenser units outside has a disconnect right there so you don’t even need to turn off the power at the breaker box. Just pull that disconnect, open up your outdoor condenser unit, snap a pic of the specs on the capacitor (it’s the only thing that looks like a soda can) and order one off Amazon and stash it somewhere. It’s a tiny part. It will take like 5 minutes max and save you several hundred bucks and a lot of sweat eventually. FWIW, when ac dies it’s usually in this order of root causes: Float switch: your condensate drain line got clogged because it just does and you need to clear it. You can proactively prevent this by pouring bleach or vinegar down the line periodically (what clogs it is usually some sort of gnarly plant like growth from all the moisture) or if it’s clogged you need to clear it. The hvac guys will charge you 300 bucks to blow pressurized air through the pipe or you can literally just duct tape a wet shop vac to the thing and suck it out yourself. Attachments can be purchased on Amazon for reasonable price. A capacitor issue is the second most common. If it ain’t the float switch almost always it’s the capacitor. You can increase your capacitor longevity and also decrease your electric bill by changing your air filter regularly but also hosing down the outside condenser coils every few months or so. Almost everyone knows about the air filter but few people know about hosing down the coils. This makes a HUGE difference. We are talking like 20-30% of your electric bill in hot climates if you don’t do it. Just take a hose and spray downward on the grates and get all that dust and dead grass from mowing out of there. You won’t hurt the thing. Why does this help? Well, it’s better to think of AC not as adding cool air. There’s no such thing as adding cool air. Only removal of heat. How does heat get removed out of your house? Through that condenser unit. If those grates are clogged up the heat cannot escape and the unit must work harder to do less effective job. So keep those coils clean. Everything else after that is way less common. Yeah compressors do die. Motors die. Refrigerant leaks. Computer components die. Thermostats fail. However it’s very rare that the issue is something other than these two things in comparison. Like probably 80% of all HVAC residential calls are probably the above two things I mentioned.

biggc 2y ago
How big can these capacitors be? Does replacing it require any safety precautions besides turning off the power?
- pxx 2y ago
  the capacitors are connected across the motor windings and are there essentially as a way to shift the phase of the current waveform. note that this is a two-phase power special; you don't need start or run capacitors if you're using 3-phase power (uncommon in North American residential settings, but YMMV worldwide) when power is disconnected they are not charged at all. it's not like the capacitors you might find in a CRT
  - rocqua 2y ago
    So what you are saying is that the capacitors are effectively shorted with the motor coil, and hence they have a drain resistor that has effectively no resistance?
- deleted 2y ago
  [deleted]
- SOLAR_FIELDS 2y ago
  The capacitors size themselves are small. They slightly vary but are almost always the size of a medium Red Bull can. They are sized to your unit though so you can’t just buy one without looking at the specs and expect it to work. But the specs are printed on the side of the can and if not can be derived from the specs on the unit itself. As far as their danger there really isn’t any beyond getting shocked from dealing with live wires. Technically they can retain a bit of a charge so I’ve seen recommendations to wait X amount of time before touching them with your bare hands or to discharge it by touching it with an insulated screwdriver to discharge it but the risk is pretty low. Once the power is off (either at the breaker or via the disconnect at the condenser unit, power only goes in one way to those things so if you turn it off in one place there’s no way you’ll get a zap) it’s a soda can with 3 wires going into it. You just disconnect the 3 wires from the old soda can, remove it, replace and connect the new one. Not that much harder than changing a light bulb.

Nursie 2y ago

The great thing about Australia is that that is probably illegal here. We've got some pretty fucked up protectionist rules about what you can and can't do in/to your own home. It's nuts. Now, nobody is actually watching most of the time, so you're usually fine, but it's as stupid as being illegal to replace a tap or existing light fitting. Every so often state governments review the rules and get swamped by trade associations who say the rules are there to prevent people being 'scammed' by untrained 'handymen' and are there for your own protection. This regulatory capture means that legally you need to complete a four year apprenticeship before you're allowed to change a plug! And another one if you want to do any basic water plumbing. I wouldn't be surprised if what the guy did in this blog is strictly speaking illegal - for instance when it comes to data cables, you need to be a qualified electrician with data specialty to install them. You can plug ethernet cables into your computers yourself (wow! such privilege!), but if you install them even by getting some stick-on plastic conduit and passing the cable through that, you're in contravention and could potentially be fined, up to thousands of dollars. For sticking some plastic tubes to the wall in your own house.

SOLAR_FIELDS 2y ago
Reminds me how, in USA, it’s the only civilized nation I’ve been to where you must have a prescription to purchase contacts and glasses. Everywhere else I’ve been will just sell you whatever magnification you need at the pharmacy. Obviously there is some acceptable line here, but I think the States handles this decently well enough. In Austin where I live you can get what is called a “homeowners permit” in a lot of cases. Meaning the city will come look at your work and as long as it’s up to code you get a legal permit just like a contractor would get (https://www.austintexas.gov/page/homeowners-permit https://www.austintexas.gov/page/homeowners-permit). You can only do this to your own home so it’s not a shortcut to running a chuck in a truck business without a license.
- Nursie 2y ago
  Yeah in the UK where I spent most of my life, it seems like you do whatever you want, pretty much. Golden rule - you don't touch gas plumbing. And you don't mess with your circuit breaker board/RCDs etc. I think installing new ring circuits may be off limits. Anything else? Go for it. I fitted a bunch of taps and a toilet, changed single sockets to double+USB sockets, changed light fittings, fixed poorly wired lighting circuits, installed Cat-6 through the walls to a few rooms, all sorts of stuff. And none of it was anyone else's business. You can (should?) get a professional inspection and safety certificate before you sell the house, but that's about it AFAICT. I'd be happy enough with the situation in Austin, so long as the city inspections were cheap or free. I'd be happy enough to do a short course in the basics before getting some sort of permit. Where we are now is nuts. (But at least I can buy a pair of generic reading glasses pretty much wherever here!)

XorNot 2y ago

The nice thing about my Mitsubishi Heavy Industry units is I've got a bunch of MHI-AC-Ctrl[1] modules tucked into them talking to the service interface with Home Assistant. The neat thing is it doesn't just control it, it also makes all the internal sensors and codes available. What I think we really need to do though is make publishing these control standards mandatory under right-to-repair laws - no one should need to be reverse engineering them, you bring a product to market you have to provide the complete spec for it's software interface and data. Do that, and I bet we'd find in a few years every new appliance would support a common serial port standard and come with a code page in the manual for it (ironically the prevalence of Tuya-smart stuff has come very close to making this happen, but they go to absurd lengths to lock you out of the wi-fi microcontrollers). [1] https://github.com/absalom-muc/MHI-AC-Ctrl https://github.com/absalom-muc/MHI-AC-Ctrl

cbanek 2y ago
I'd love this, but right now I'd be happy with a team reverse engineering these things and not getting hit with some kind of IP lawsuit from whatever company. I think there's going to be a lot of abandoned-ware IoT stuff, mostly because the company wants to turn the software off because they don't make money from supporting old products. My fitbit wifi scale, which I love and has been doing a great job for the last 10 years has now lost support to pair it with the new fitbit app, thanks Google!
- XorNot 2y ago
  One problem I've found with a bunch of my own stuff though is microcontroller firmwares. Tons of devices have some type of microcontroller running them, and if the CPU is what goes (which happened on a bunch of Yamaha amps I've dealt with) then it goes right up in the air as to whether sourcing a replacement part is practical because you can't even get a binary blob to shoot onto it.
girvo 2y ago
Oh hey, thats neat. I have two MHI split systems in my house! Definitely going to have a play with this, very nice.

refurb 2y ago

I did something similar for a clothes drier. The thing was ancient (mid-80’s) but was fantastic. It was huge and you could dry maybe 3 comforters under an hour. It stopped heating and it turned out there are solenoids that control the natural gas flow. Quick disassembly (back when products were made for easy repair) and swapping out two $8 solenoids from Amazon and I was back in business.

jamiek88 2y ago
And doesn’t it feel great? Unironically one of the proudest moments of my life was when I fixed the the belt on our dryer. A $10 rubber belt and YouTube and voila!
Scoundreller 2y ago
Gas hot water heaters will often foul the flame detection sensor over time. Simple YouTube video to unscrew the thing, sand off the crud and back in action.

ApolloFortyNine 2y ago

Everyone reading this should find out what capacitor they need and buy one off Amazon, they're all <$20. I've done this repair myself, it takes maybe <15 minutes and is almost impossible to mess up. Even if you were find spending a couple hundred dollars to have someone come out and do it, you'd still go hours at least without AC. Which depending on the time of year can be miserable.

Scoundreller 2y ago
> and is almost impossible to mess up Just don’t cook yourself with the remaining good capacitance. Personally, I wonder what could be done to temporarily get the capacitor to “kick” for a few more times to get your home temperature down as you get your replacement. Chill the capacitor?
- BizarroLand 2y ago
  It depends on the failure mode of the cap. If it has blown its dielectric, then chilling it may cause the plates to separate enough to boost the capacitance, but it is more likely to just be a waste of time. Aside from that, you could strap on other capacitors as long as their voltage is the right value. A daisy chain of 50mf capacitors to shore up the blown capacitance might buy you a day or so of usage. Best bet, if you have an old broken microwave nearby, would be to pull the cap from it and wire it in.
quickthrowman 2y ago
Please don’t suggest buying electrical parts off Amazon, that’s criminal negligence. On second thought, please do not give any electrical advice on the internet. Buy it from McMaster Carr or Grainger, please!! If you do this repair yourself, short the contacts of the capacitor (ideally with a correctly sized resistor) to discharge it before handling it so you don’t electrocute yourself. Start caps: https://www.mcmaster.com/products/motor-starter-capacitors/ https://www.mcmaster.com/products/motor-starter-capacitors/ Run caps: https://www.mcmaster.com/products/run-capacitors/ https://www.mcmaster.com/products/run-capacitors/
- 2y ago