OMFG; I am in Perth, I have the same system, the very same problem and solved it almost the same way and was in the process of writing it up.
The system uses RS422, with a base64 encoded AES key in the aaservice binary, and I was contemplating building an esp32 based open source implementation of the controller.
What the hell, why does a control system need an AES-secured control channel at all? The only possible intention is to make interop more difficult. If they wanted security then they wouldn't use a hard coded AES key.
Anti circumvention laws don’t require good locks to provide the manufacturers a legal cudgel to use against anyone with the temerity to think they have the right to use and fix things they have paid for. The law (DMCA in the US, it looks like something called the Digital Agenda Act in Australia) is the real lock, not that AES key.
In theory, connected devices that control large energy loads ("large" on a household level of energy consumption) can be coordinated at scale to "attack" the power grid via instantaneously switching 1000's of units on and off at the same time.
That being said it's more likely the hardware mfg is just trying to claw in more margin.
I've got one of these systems too. Mine hasn't died yet, touch wood, but I was concerned enough about the possibility that I went as far as documenting the comms protocol and starting to design a pi hat to talk to the main control board.
Do it!
I don't live in Australia or have on of these systems, but I was intrigued by how the OP had gone around the company to save themselves 1500! I'm curious to see how people are resolving things like this, so that if I have issues myself sometime, I have ideas on where to start or what is necessary :)
sounds like the memory storage is failing on some sort of logging systems for these to be going down at the same time-ish (same number of logs per day written etc over cheap flash).
It is a conversation I have had with many a jr dev. 'ok you are logging this how much space is that going to take? how long do you want to keep it? what is your rotation schedule?'
I usually get the 'oh did not think of that' because logging is a serious afterthought in many cases. It is boring and you just drop in log4j and log away right?
Reading the original post, wouldn't be a super cool idea to make a little ESP or RPI based system which acted as a controller for the airco and a network bridge? Then literally anything could interface with it. You wouldn't even need to wire it up. No need to install some shitty app from a company who are quite clearly c*ts.
I'm sure that they made things more difficult by employing proprietary hardware wherever they can (also to discourage competition), but yes, there are a bunch of sensors and actuators in there and any board with the appropriate i/o capabilities should be able to interface to them, however writing a working firmware would be next to a nightmare: how do you find developers who want to spend months reverse engineering an AC and also know enough about ACs to put together something that works?
Replacing household appliances brains with open counterparts would be a heck of a business opportunity to revive or prolong the life of dead/obsolete products, however I guess finding people who are interested enough to do that with FOSS, essentially selling only hardware and installation services would be really hard.
Timezone effect, I think. Just us and the whole of East Asia online now. The Poms and Europeans are just about to wake up, and the Americans have logged off for the night.
They skimped on the tablet, grabbing a <$100 device for cheap. It should be a ruggedized / semi-industrial device with an expected lifetime as long as the device it controls, so at least 15-20 years.
You have no idea how true this is :). I had to upgrade everything, the old site didn't even have SSL. But this annoyed me so much I wanted others to know how to fix it.
Super fun read. Reminds me of the old software cracking days… totally appreciate you sharing it, even though i likely will never have one of those AC units.
> You have no idea how true this is :). I had to upgrade everything, the old site didn't even have SSL. But this annoyed me so much I wanted others to know how to fix it.
People like you are the ones that make the internet worth logging on for.
I have some freak brain (and IKEA experience) which usually let's me do IKEA pretty well. What was it that happened in your case? I'm curious what brought you to that point.
I love it too but this only becomes worthwhile if you manage to promote this post in social media somewhere. If you don't already have a strong social media presence or don't personally know anyone who does you can forget about it.
And here on HN you really have to get lucky, post at the right time and hope the flagging gangs don't get you.
I could not disagree more. This sort of thing is a public service. Even if only a dozen people find it valuable, it can be exceedingly valuable to them. It's worth putting this sort of thing on your website for that reason alone.
It just doesn't matter that much in my experience. If an issued command didn't work, it's easy to tell anyway (it's hot/cold), and you can just repeat it. HomeAssistant also has bits of special handling for items that don't communicate their state back, called "assumed state".
For the rare times I want to control my AC when being away from home, I have an air monitor nearby. I can just check if the temperature/humidity has changed, and repeat the command if it didn't work. If you _really_ cared you probably could script it to do it automagically, but I didn't feel the need to bother.
The remote has no feedback. I have found Tasmota IR 100% reliable over 3 years.
It sends the whole state on every transmission so the IR has no receiver.
If the message sent over IR always contains the full state, then it's only a matter of checking that the message was received.
If you are in the room, you'll know soon enough, otherwise I guess it could be possible to rely on the audio feedback (a light beep) that the AC probably emits when it successfully receives a command. (and add a temperature sensor to check that it's working properly)
AC is typically something you only need when you are inside the house so it is not like any freak situation would occur. If it happens only super occasionnally at worse you just set it the homeassistant state using the remote manually.
I guess you should hide those remote in a drawer and remove the batteries when you start using homeassistant
Similar problem here. I've thought of getting IR receivers to also listen for the remote's IR signal, since you have to be able to encode the IR protocol anyways. But even then sometimes the AC unit doesn't get the signal from my remote, so I'm unsure if that's a remote issue or receiver issue.
The completely overkill setup would be to get a different remote control, get my DIY receiver to accept that and convert it to my AC unit's IR code, updating HA while at it. The remote's state would be out of sync still, but it'll keep the units in sync with HA.
A lot of remote controlled air conditioning systems (like mini-splits and windows units) send the entire state of the remote via the IR blaster every time a key is pressed so there's no chance of the two getting de-synced.
I got the Daikin for the same reason. You have to pay extra for a wifi module but after reading the reviews on their app, they mostly said, it kinda worked but largely useless.
I built an esp32 IR sender and put Tasmota IR on it. It has first class support for the Daikin. It can't receive but it seems no need as it's 100% reliable.
For Daikin, https://github.com/revk/ESP32-Faikin works well, and is tidier (and I think more featureful?) than an external IR port. Its existence is why I bought a Daikin!
I have a lennox heat pump in my house and the main thermostat controller went out a few months ago.
Lennox uses a proprietary system like this one but the old school controls were visible on the control boards and due to a freak accident when an installer was levelling the floors for new flooring and cut the old wire I had a 5 wire thermostat wire installed instead of the 4 wire it came with.
Perfect.
$50 thermostat, wired it in. Powers on. Fan powers on. A/C condenser? Nada.
Official replacements were $700+, upgrades were $800.
Checked around, found an offerup seller selling the upgraded model for $400. Deal.
Met the guy, he gave strong, "I stole this, don't ask too many questions" vibes at first glance, and I was about to back out of the deal, but something clicked in my gut and I went with it.
Got it home, wired it up. Fan turns on. No AC. @#$@!#$%@#$^
On a hunch, went outside and checked the power for the heat exchanger. I had unplugged it for safety reasons but plugged it back in afterward, but gave it the snuggy test just in case.
Sparks shot out as it re-engaged. It's Alive!
The $50 one might have done the job, but no point in re-rewiring the whole shebang as the money is already spent.
If this system goes down, I'm going mini-split ductless. Forget this noise.
IR is fine for these things, it's not like they need much data. I have an IR ceiling fan, no issues there (even if the receiver is on a little wire that is supposed to stick to something but the sticktivity of the tape sucked), and a radio "smart" lighting system (just simple on / off switch on a plug socket). And some radio spots from IKEA, although I'm sure that can be hooked up to a "smart" system.
IKEA has consistent smart system that has the annoying feature that it works the wrong-way around for my use-case. The cheap IKEA switches can control IKEA peripherals only directly, you can't use them to control something outside of the IKEA ecosystem. As most of the things I want to control are either HomeKit native things or digital outputs on PLCs it does not work for me. So in the spirit of true overkill I have few switches that contain OrangePi Nano (I had somehow absurd quantity of these laying around as leftover from previous even more misguided project)
I did the same, i recommend getting the moes or similar IR blaster (tyua under the plastic). Treat yourself and get a combo temp/humidity sensor + IR.
For one of the rooms i opted for a IR/RF transmitter and the RF covers any RF enabled devices in the house (433mhz + 315mhz[i think but haven’t tested])
I also just got AC last year, and while it doesn't have as many fancy features I'm glad I got one that works with standard 24V HVAC wiring. I built my own thermostat out of an ESP8266, I²C temperature sensor from adafruit, and three TRIAC circuits to control the fan, heat, and ac wires. Connected to MQTT and I can send control commands to it from my Home Assistant instance!
If you have the code for this publicly (or would consider making it so) I would be quite interested in it.
There are a fair number of DIY thermostat projects online, but all that I have found were one-offs by their creators, or were for specific kinds of systems like boilers.
I've been batting around the idea of starting a general-purpose IoT thermostat that only uses cheap, widely-available components that anyone can easily duplicate with a BOM and 3D printer.
Ah, do you have some tips for someone who wants to do something similar?
I use AC units that come with IR remotes (Samsung maybe??) but the timers don't work for some reason. It would be great to hand roll some automation, but I never "hacked" IR remote/receiver systems.
funny - I literally bought a broadlink ir blaster today and got it hooked up to HA about 15 minutes ago, looking to do this exact same thing.
Out of curiousity, did you have any resources you were following to set this up? I'm pretty new to HA - basic devices etc seem fine, but I'm not entirely sure where to go next!
I'm using Broadlink RM4 Mini's I got off AliExpress. They've got a powerful enough IR signal that I've found I don't need them sitting way out in the open and obvious. One is tucked behind a TV and not quite in direct LoS, one is behind, but it reflects off the wall just fine, another behind a bedside table.
For the integration/Climate control thing I'm using SmartIR. Configuring it is a bit weird, you have to put it direct into the configuration.yaml file unlike other integrations.
Reddit and Google was how I chose which one to go with.
The Broadlinks RM4 minis were pretty cheap on AliExpress. I think I paid about $15 each? Might have to wait for specials to come up to get the lowest price.
Ugh. The whole "smart aircon" industry needs a good-sized asteroid wiping them out of the existence.
There is a very real need for modern variable-speed units, and vendors just keep fucking it up by using proprietary protocols locked into their ecosystem. TRANE in the US is similar.
And this is really annoying because variable-speed pumps solve all the problems with short cycling and oversized systems.
I think there's probably a case for some regulation to force at least a minimum set of open standards, because that would make it possible to e.g. switch between systems based on intermittent renewable generation etc.
Also there's the variable-speed furnace/AC fan. These heavy bastards, with an add-on brain, are very expensive when they go bad. In my case, the brain part was fine, but the fan motor died. They wouldn't sell me just the motor, just the combo for $900US! And, if I install the combo, it voids the warranty. (I did install it, I'm the homeowner not a repairman.)
I was also told if my unit was a Trane, they weren't allowed to sell me the combo! (My unit is a Goodman.) What a rip off!
I think home EV charging equipment is heading in the same direction as well. Very few have local and open APIs and instead depend on the vendors cloud service for control.
At least swimming pool equipment is mostly just turning things on and off. If you look at the controller board for any given pool "timer" it's just a bunch of relays (for the pump, lights, and valves/servos).
Temperature sensors are all standardized for the most part (well, they don't seem to be anything special) but I'm not sure about chlorinators... Mine has a strange (electrical) connector and 100% proprietary threads on the PVC connectors (that were easy enough to reverse engineer in OpenSCAD: https://www.printables.com/model/24144-t-cell-cleaning-stand).
Fortunately there's plenty of 3rd party competition for things like that. Even though I had a Hayward system I was able to purchase a compatible chlorinator off Amazon for a fraction of the price Hayward was charging.
I just spent an afternoon recreating the custom threads on a Hayward chlorinator for my dad so I could 3D print a temporary replacement part. These don’t even use standard pipe fitting thread. -_-
I am looking at replacing my A/C system, and having worked on the single stage single speed one that's currently installed, and looking at the insane shit everyone ships that's more complicated than your basic gas forced air furnace coupled with a single stage 16 seer A/C unit, there's no way I would ever buy something else. Every parts house has got inexpensive replacements in stock for the simpler units and service is easy; good luck if you have go find the unobtanium variable speed motor or control board that Lennox or Trane just happened to stop making the moment your unit stopped working.
Largely my take as well... I just want the simplest thing that works at this point... I'm heading in that direction as I need to replace appliances as well. So far this year, the microwave, range and dryer have all died. The microwave was the single biggest safety hazard I've ever seen, and they say you shouldn't work on them yourself... what happens when it turns on if the door is open? Or, you discover later, it's actually just on all the time even though the light is off and the fan isn't running.
I'm all about stupid, but repairable appliances now.
Yep, and it's annoying because variable speed units themselves are _better_ than the old classic one or two-speed units. They are more economical, quieter, and mechanically more reliable.
It just takes time for all this stuff to iron itself out. Consider how long it took for practically every heating and A/C system to become largely the same.
The problem with having standards for this kind of thing is that different units have different needs for communication and different levels of being smart. For example, some units want 2 temperature sensors and some want 3. The method used to control the system can be relatively complex - some systems are using physical models of the characteristics and positioning of sensors to do fancy control, and there are probably at least 5-15 data points involved in a typical system.
While it would be nice for the protocol to be documented (would realistically only be used by a very small number of users), the only real way you would be able to get a standard for something like this to work is if you went the Bluetooth route and did generic scenario-based profiles (e.g. HFP, A2DP, SPP), and optionally some "GATT" or "generic attribute" parameters. However, as we see with Bluetooth LE, everyone just uses GATT and implements their own little proprietary thing over it and you're back to the same problem.
Some of these systems attempt to be "smart" and just use the 24V C/W/Y1/Y2 etc protocol as a "standards compliant fallback". You don't necessarily lose ALL of the smarts, but the unit has to essentially use physics magic to make an educated guess about the information (for example, if you use a on-off thermostat, you can't really measure the temperature of the setpoint, so you don't know how close you are unless you somehow make an observation over many cycles.
I think that reasonable attempts to address this problem could involve some kind of extension to the old 24V interface - say, by offloading the actual "policy" part of system control to the "thermostat" i.e. have something that goes from 0-10V where 5V is off, 0V is full cooling and 10V is full heating. This allows you to choose your own temperature sensor situation, but complicates setups where more than one zone or thermostat is required. Of course, it will be very difficult for the industry to settle on a solution to this. Qualcomm's Quick Charge 2.0 was a very simple protocol similar to this, which was essentially self-documenting and not something that needed versioning, but of course, needs changed, 3.0 came and went, 4.0 came and went, and by the time USB C and USB PD came around you ended up with a full on data protocol API with all the OSI layers and of course, vendor specific extensions.
You could define some complicated protocol where you don't conform to a standard but you publish an API for your system (of course, there is no incentive to do this), and larger vendors like Control4 or Lutron, Crestron can program their products to interface with it. Unfortunately this doesn't allow the customer full choice over thermostats, because now you have to deal with N vendors x N thermostat vendors, which isn't scalable and you'll end up in dependency hell.
The closest thing I can think of to a standard, and the way it is solved in larger buildings, is through something called BACnet. It appears to use the Bluetooth model of "scenario based profiles", with all of the disadvantages that come with that, but the primary disadvantage is that it has to be to some degree manually configured to route data where it needs to go - and I don't think this is something installers are currently equipped to do at home scale.
Realistically, the "thermostat" is just a vestigial component in modern terms and really, it's just a user interface and thermometer now. Without getting into the wish to have open sourced app control or whatever, it's hard to define what the "thermostat" does and what the "system" is doing, and whether the device that sits on the wall is really a "thermostat" deserving of being interchangeable anyway. I have heard from a friend that does home automation integration that many clients don't like the default thermostat because it doesn't look very aesthetically pleasing. In this case, I'm definitely sympathetic to the need for customizability but it seems difficult to achieve in practice.
Make it a certification requirement (UL or whatever) for the manufacturer to maintain a gold-level OSS Home Assistant integration, and all those problems would solve themselves in a heartbeat.
Alas, vendors that interface with customers do not sell appliances - they sell "solutions", specifically solutions to the problem of their own making, i.e. them inserting themselves between the buyer and the appliance they're buying.
> The problem with having standards for this kind of thing is that different units have different needs for communication and different levels of being smart.
There really is nothing complicated there. I have some background in lift (elevator) systems, and they have similar requirements. Modern lift systems use variable frequency drives for smooth start/stop, and they came up with compatible protocols that allow users to mix-and-match controllers.
In the end, there just needs to be a simple protocol to command the motor to run at a certain speed. It can be CAN-based, it can be based on RS-485, etc. For additional smarts, throw in readings from the sensors inside the AC units (pressure, coils temperatures).
Then the control units can be made by third parties. They can do all kinds of prediction-based logic, complicated PID controllers, whatever.
> Some of these systems attempt to be "smart" and just use the 24V C/W/Y1/Y2 etc protocol as a "standards compliant fallback". You don't necessarily lose ALL of the smarts
You actually do with TRANE units. They become completely dumb, not even 2-stage emulation.
> The closest thing I can think of to a standard, and the way it is solved in larger buildings, is through something called BACnet.
I have BACnet at home, for wired temperature/humidity sensors, the same RS-485 network is also used for Somfy shades ( https://github.com/Cyberax/py-somfy-sdn ). BACnet is a low-level system, and it needs higher-level profiles. But yes, exposing the motors and the sensors inside the AC units over BACnet would be a great start.
Very convenient for them and also easy to accomplish by buying the cheapest parts. It's probably eMMC-based and writing a logfile constantly. Source: every Android that has ever died on me in this exact way (four and counting)
It's been a big pain for Tesla as well, where their tiny 8GB emmc on the center screen would fail since they logged to it too much... 134,000 vehicles recalled eventually after they denied it was an issue.
I recently had to fix the radio in my car for the same reason. Pioneer installed the firmware onto a cheap SD card that they have hidden inside the radio and requires disassembly to replace. Of course they don't offer the original firmware anywhere, luckily someone online has backed it up and I found the file on reddit.
I recently had an otherwise perfectly fine eMMC-based Samsung phone degraded to unusable floppy disk speeds.
My guess is that their "RAM Plus" feature (aka swap) combined with the memory hungry modern android apps turned out to be a nasty timebomb. Which has or still is bricking millions of smartphones after a few years of usage.
knowing a lot of these companies. it wouldn't really matter if it fell inside of the warranty. they would simply screw a lot of people over until there's a class action lawsuit (or whatever equivalent is in that country) where they get a slap on the wrist for not honoring warranty claims.
Carrier back in the 2000's had a problem with their heat exchangers in their gas furnaces failing far more often than they should. They were sued, settled, and part of the settlement was an extended warranty of the heat exchanger, including labor.
Great, right?
The local carrier dealer lied and said the unit wasn't under warranty. They lied again when reminded of the class-action settlement, claiming only part were included and said would cost a fortune in labor.
When I called Carrier and told them what their factory authorized gold/preferred/whatever-they're-called dealer was pulling, Carrier confirmed I was correct and even verified the unit's serial number and said that if the dealer had checked the SN, they would have found it was covered.
The dealer then said 'fine, but those parts are going to take weeks to get from the warehouse' knowing damn well I had no heat, in the winter. They had us over a barrel and they fucking knew it, and I didn't have any way to prove that claim wrong.
My A/C unit is fairly new but there are signs the condenser unit fan is starting to go. Since it is still under warranty for parts (not labor) I thought I would be able to just get a replacement fan and install it myself. But no, the manufacturer will only deal with a "certified technician," who of course charges an outrageous amount of money (many hundreds of dollars) to replace the fan. When I asked the technician why the labor cost so much, they gave me some song and dance about how the prices were set by their central office (true) and that the cost also included filing the paperwork to make a warranty claim (seriously?).
At the end of the day, I could probably buy an aftermarket fan off the Internet and install it myself, spending far less than the certified technician would charge to install the "free" OEM replacement part.
I had a Phillips 4K LED TV I purchased on sale in April 2021. The TV was glitchy, and I'd get all sorts of weird problems with it - but nothing really terrible.
Then two weeks into January this year, the picture suddenly becomes a jumbled mess of vertical stripes. One second it's fine, the next second it's broken.
Luckily we have a general 5 year warranty period here in Norway, and TVs are expected to last for at least 5 years. I called the shop, and they told me to just bring the TV.
When I get there with the TV, I notice two other identical TVs. I check out the note that hangs on them, and see that they are broken, with the same symptoms as mine. Both had purchase dates around March / April 2021.
> What a fun, completely coincidental quirk that that time appears to fall outside the warranty window, hey?
Isn't that the point of the warranty? They tell you they think the product will last for X years, and then it lasts about X years, just like they warranted.
HVAC systems are usually advertised as lasting at least a decade, but the warranty is usually only a year or two.
Honestly, I think something needs to be done so that companies are held liable for expensive products failing and needing expensive repairs after a year or two.
I don't think they'll care about this. Probably only 1% of their customers are capable of "hacking" this. As long as the tablet replace is cheaper than getting a new AC unit from another company it's fine for them.
Yes, which is very sad. Nearly all things go into this direction. I still remember the old days of jail breaking the iPhone, and the cat and mouse chase with Apple.
They would have to put the condition inside shared library .so and use Android JNI. Make it complicated and hide the string tablet model throughout the code, just enough time to frustrate whoever is decompiling the so file.
If they want to really do it wrong (or right, from their PoV), they require the communication with the base station to be signed with a certificate signed by their root CA, and put the private key of that certificate in the TPM.
In defense of this, remember that any random person can download and install this app on any android device. It does make sense to have a clear failure mode in this case. Anyone willing to pull out a soldering iron to attach a new tablet is perfectly capable of working around this.
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).
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.
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). 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.
Australia is definitely one of the most rule-obsessed countries, even in comparison to Germany, where I’ve lived for the last decade or so. Parts of my parent’s house back home are heritage listed, some rules make sense and some are bizarre, especially regarding the garden.
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).
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!
Network-connected home Mitsubishi units can be controlled with the MELCloud API (same api used by mobile app) which makes it easy enough to write scripts that grab current temp, settings, power usage.
Perhaps someone has already made a home assistant plugin that does this?
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.
You have to be careful with Amazon/eBay caps, as they can be cheap chinesium garbage. I look for name-brand caps when I can and try to get them off eBay, Grainger, or Repairclinic.
You don't need the same model number as the original cap, it just has to have the same voltage rating, capacitance, and number of terminals. You might have to get creative with the mounting solution if the new cap is different than the old one in terms of shape or size.
Also, pro-tip: when you replace a the cap in the outside unit, install it upside-down so that water doesn't pool on top of the cap and rust it out from the top.
I have a gas furnace and I also keep a spare ignitor handy. It's not a matter of "if" those go bad, it's "when."
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?
Don't buy electronics components from marketplaces of any kind. There are reputable parts suppliers and for things that are common and in stock it will probably even be cheaper and faster than buying the same thing (of unknown provenance and quality) from who knows what seller on random marketplace.
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.
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.
+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...
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.
I want to emphasize for others how important this comment is. I live in suburban Atlanta and last month the AC failed. Can you guess what day and time it failed? Yep, 8AM on 96F/70% humidity SUNDAY. And we moved into this f*cking old house a year earlier after moving across the country so no local knowledge of contractors. After about 15 minutes in google maps I call up my best guess based entirely on internet vibes. After some hemming and hawing which is best described as a verbal biopsy of my wallet ("it's going to be $200 for showing up") the dude shows up. We get to talking as one does (I DIY everything) and he says I'll show you how to fix it, it's very likely the capacitor is the problem.
So he unscrews the panel, pulls off the leads, puts in the new capacitor and voila.
Then the guy says basically exactly what the above para starting with "A capacitor issue...", including hosing down the coils.
So in 10 minutes I learned another mandatory skill on a Sunday morning, and it only cost $675. (Yes I know better than to place my tongue across the capacitor connectors)
Last year I fixed the condensate drain line clog myself, by uh, well, I was in a hurry, blowing into the pretty grotty drain line. I did purchase the exact model pump for a spare.
> But HVAC supply shops will sell them to you, you don’t need to be licensed or anything to buy them.
My local HVAC supplier doesn't sell to non-licensed people. I think they don't like dealing with returns from people who don't know what they're doing. I needed a 24vac transformer once. My dad used the same HVAC company for his office for a long time, they still remembered him, and had the part I needed in stock.
Two summers ago my AC didn't sound right. IIRC the outside unit was clicking on and off. I pulled the breaker. Eventually I decided the problem was with the contactor (a switch controlled by 24vac). I took pictures of where the wires were connected and pulled the contactor. For no particular reason I started taking the old contactor apart, and found a cricket in the middle. I removed the bug, cleaned out the cricket residue, put the contactor back together, and returned it to the outside unit. My AC system resumed working perfectly. https://en.wikipedia.org/wiki/Contactor
It's actually worse than that here in Austin. The was only 1 store that would sell me a individual capacitor when mine failed. That one failed about 3 days later. I did some research online and apparently there was just a massive production run of capacitors that were imported to the US and are known to be bad. Supply houses were just looking to offload them.
Now I could take it back for a warranty replacement, which would give me the same defective unit.
As a result of this, I don't even recommend buying components locally any more. The capacitor from amazon cost about $12 and is still working years later.
Readit News
The system uses RS422, with a base64 encoded AES key in the aaservice binary, and I was contemplating building an esp32 based open source implementation of the controller.
That's a crazy weird coincidence.
https://www.aliexpress.com/item/1005005918675239.html
The connectors on the small RJ45 daughter board are JST-SH 1.0
The yellow lead puts out 4.2v to replicate a Li-Ion battery (as far as I can tell). You can ignore this.
Red is positive
Black is negative
Green is usb d+
Blue is usb d-
https://git.nethack.net/rob/aircon
Essentially it just talks to the android tablet API to do things so it's no help if (when) the tablet dies, but it means I can do things like:
- have the entire unit turn on/off as needed based on average zone temperatures
- open/close vents based on room owners' devices being online, or temperatures of nearby zones
- dump zone temperatures to influxdb
That being said it's more likely the hardware mfg is just trying to claw in more margin.
I should really write that up at some point too.
Shame on this manufacturer.
I usually get the 'oh did not think of that' because logging is a serious afterthought in many cases. It is boring and you just drop in log4j and log away right?
https://www.quora.com/Why-are-West-Australians-called-sandgr...
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People like you are the ones that make the internet worth logging on for.
(solid post, also solid rant, mate)
I would have used wood and nails. You must have terrifically strong emotions!
I specifically went for units that were IR controlled rather than any proprietary smart B.S.
For the smarts, I used cheap IR blasters from AliExpress and hooked them up to HomeAssistant.
I just mounted cheap Lenovo tablets to the wall to do the room-dashboard thing to allow controlling lights/AC without a phone.
These kind of horror stories only serve to reinforce my decision.
https://smartlight.me/smart-home-devices/wifi-devices/wifi-d...
https://www.youtube.com/watch?v=f6GEfzVhwCE
Since there's no feedback mechanism, how do you solve for when the state of the unit(s) gets out of sync with HomeAssistant's?
It just doesn't matter that much in my experience. If an issued command didn't work, it's easy to tell anyway (it's hot/cold), and you can just repeat it. HomeAssistant also has bits of special handling for items that don't communicate their state back, called "assumed state".
For the rare times I want to control my AC when being away from home, I have an air monitor nearby. I can just check if the temperature/humidity has changed, and repeat the command if it didn't work. If you _really_ cared you probably could script it to do it automagically, but I didn't feel the need to bother.
https://tasmota.github.io/docs/Tasmota-IR/#sending-ir-comman...
If you are in the room, you'll know soon enough, otherwise I guess it could be possible to rely on the audio feedback (a light beep) that the AC probably emits when it successfully receives a command. (and add a temperature sensor to check that it's working properly)
I guess you should hide those remote in a drawer and remove the batteries when you start using homeassistant
The completely overkill setup would be to get a different remote control, get my DIY receiver to accept that and convert it to my AC unit's IR code, updating HA while at it. The remote's state would be out of sync still, but it'll keep the units in sync with HA.
I have Zigbee contact sensors that provide on/off feedback to HA by detecting if the louvers are open.
I built an esp32 IR sender and put Tasmota IR on it. It has first class support for the Daikin. It can't receive but it seems no need as it's 100% reliable.
Lennox uses a proprietary system like this one but the old school controls were visible on the control boards and due to a freak accident when an installer was levelling the floors for new flooring and cut the old wire I had a 5 wire thermostat wire installed instead of the 4 wire it came with.
Perfect.
$50 thermostat, wired it in. Powers on. Fan powers on. A/C condenser? Nada.
Official replacements were $700+, upgrades were $800.
Checked around, found an offerup seller selling the upgraded model for $400. Deal.
Met the guy, he gave strong, "I stole this, don't ask too many questions" vibes at first glance, and I was about to back out of the deal, but something clicked in my gut and I went with it.
Got it home, wired it up. Fan turns on. No AC. @#$@!#$%@#$^
On a hunch, went outside and checked the power for the heat exchanger. I had unplugged it for safety reasons but plugged it back in afterward, but gave it the snuggy test just in case.
Sparks shot out as it re-engaged. It's Alive!
The $50 one might have done the job, but no point in re-rewiring the whole shebang as the money is already spent.
If this system goes down, I'm going mini-split ductless. Forget this noise.
For one of the rooms i opted for a IR/RF transmitter and the RF covers any RF enabled devices in the house (433mhz + 315mhz[i think but haven’t tested])
There are a fair number of DIY thermostat projects online, but all that I have found were one-offs by their creators, or were for specific kinds of systems like boilers.
I've been batting around the idea of starting a general-purpose IoT thermostat that only uses cheap, widely-available components that anyone can easily duplicate with a BOM and 3D printer.
I use AC units that come with IR remotes (Samsung maybe??) but the timers don't work for some reason. It would be great to hand roll some automation, but I never "hacked" IR remote/receiver systems.
Home Assistant supports a huge range of integrations.
Personally I am using Broadlink RM4 Mini IR blasters. One in each room. They get added to Home Assistant as devices.
Then I use one of the climate add-ons that can send IR commands via the Broadlinks.
Out of curiousity, did you have any resources you were following to set this up? I'm pretty new to HA - basic devices etc seem fine, but I'm not entirely sure where to go next!
I'm using Broadlink RM4 Mini's I got off AliExpress. They've got a powerful enough IR signal that I've found I don't need them sitting way out in the open and obvious. One is tucked behind a TV and not quite in direct LoS, one is behind, but it reflects off the wall just fine, another behind a bedside table.
For the integration/Climate control thing I'm using SmartIR. Configuring it is a bit weird, you have to put it direct into the configuration.yaml file unlike other integrations.
I have a Broadcom one which works well but expensive.
The Broadlinks RM4 minis were pretty cheap on AliExpress. I think I paid about $15 each? Might have to wait for specials to come up to get the lowest price.
There is a very real need for modern variable-speed units, and vendors just keep fucking it up by using proprietary protocols locked into their ecosystem. TRANE in the US is similar.
And this is really annoying because variable-speed pumps solve all the problems with short cycling and oversized systems.
I was also told if my unit was a Trane, they weren't allowed to sell me the combo! (My unit is a Goodman.) What a rip off!
Temperature sensors are all standardized for the most part (well, they don't seem to be anything special) but I'm not sure about chlorinators... Mine has a strange (electrical) connector and 100% proprietary threads on the PVC connectors (that were easy enough to reverse engineer in OpenSCAD: https://www.printables.com/model/24144-t-cell-cleaning-stand).
Fortunately there's plenty of 3rd party competition for things like that. Even though I had a Hayward system I was able to purchase a compatible chlorinator off Amazon for a fraction of the price Hayward was charging.
I'm all about stupid, but repairable appliances now.
But the insane control systems compensate for it.
While it would be nice for the protocol to be documented (would realistically only be used by a very small number of users), the only real way you would be able to get a standard for something like this to work is if you went the Bluetooth route and did generic scenario-based profiles (e.g. HFP, A2DP, SPP), and optionally some "GATT" or "generic attribute" parameters. However, as we see with Bluetooth LE, everyone just uses GATT and implements their own little proprietary thing over it and you're back to the same problem.
Some of these systems attempt to be "smart" and just use the 24V C/W/Y1/Y2 etc protocol as a "standards compliant fallback". You don't necessarily lose ALL of the smarts, but the unit has to essentially use physics magic to make an educated guess about the information (for example, if you use a on-off thermostat, you can't really measure the temperature of the setpoint, so you don't know how close you are unless you somehow make an observation over many cycles.
I think that reasonable attempts to address this problem could involve some kind of extension to the old 24V interface - say, by offloading the actual "policy" part of system control to the "thermostat" i.e. have something that goes from 0-10V where 5V is off, 0V is full cooling and 10V is full heating. This allows you to choose your own temperature sensor situation, but complicates setups where more than one zone or thermostat is required. Of course, it will be very difficult for the industry to settle on a solution to this. Qualcomm's Quick Charge 2.0 was a very simple protocol similar to this, which was essentially self-documenting and not something that needed versioning, but of course, needs changed, 3.0 came and went, 4.0 came and went, and by the time USB C and USB PD came around you ended up with a full on data protocol API with all the OSI layers and of course, vendor specific extensions.
You could define some complicated protocol where you don't conform to a standard but you publish an API for your system (of course, there is no incentive to do this), and larger vendors like Control4 or Lutron, Crestron can program their products to interface with it. Unfortunately this doesn't allow the customer full choice over thermostats, because now you have to deal with N vendors x N thermostat vendors, which isn't scalable and you'll end up in dependency hell.
The closest thing I can think of to a standard, and the way it is solved in larger buildings, is through something called BACnet. It appears to use the Bluetooth model of "scenario based profiles", with all of the disadvantages that come with that, but the primary disadvantage is that it has to be to some degree manually configured to route data where it needs to go - and I don't think this is something installers are currently equipped to do at home scale.
Realistically, the "thermostat" is just a vestigial component in modern terms and really, it's just a user interface and thermometer now. Without getting into the wish to have open sourced app control or whatever, it's hard to define what the "thermostat" does and what the "system" is doing, and whether the device that sits on the wall is really a "thermostat" deserving of being interchangeable anyway. I have heard from a friend that does home automation integration that many clients don't like the default thermostat because it doesn't look very aesthetically pleasing. In this case, I'm definitely sympathetic to the need for customizability but it seems difficult to achieve in practice.
Alas, vendors that interface with customers do not sell appliances - they sell "solutions", specifically solutions to the problem of their own making, i.e. them inserting themselves between the buyer and the appliance they're buying.
There really is nothing complicated there. I have some background in lift (elevator) systems, and they have similar requirements. Modern lift systems use variable frequency drives for smooth start/stop, and they came up with compatible protocols that allow users to mix-and-match controllers.
In the end, there just needs to be a simple protocol to command the motor to run at a certain speed. It can be CAN-based, it can be based on RS-485, etc. For additional smarts, throw in readings from the sensors inside the AC units (pressure, coils temperatures).
Then the control units can be made by third parties. They can do all kinds of prediction-based logic, complicated PID controllers, whatever.
> Some of these systems attempt to be "smart" and just use the 24V C/W/Y1/Y2 etc protocol as a "standards compliant fallback". You don't necessarily lose ALL of the smarts
You actually do with TRANE units. They become completely dumb, not even 2-stage emulation.
> The closest thing I can think of to a standard, and the way it is solved in larger buildings, is through something called BACnet.
I have BACnet at home, for wired temperature/humidity sensors, the same RS-485 network is also used for Somfy shades ( https://github.com/Cyberax/py-somfy-sdn ). BACnet is a low-level system, and it needs higher-level profiles. But yes, exposing the motors and the sensors inside the AC units over BACnet would be a great start.
Any tablet worked. The only reason it die not work ootb were completely arbitrary restrictions.
The control boxes can do whatever complicated things they want. But the interface to control them should and can be standardized.
What a fun, completely coincidental quirk that that time appears to fall outside the warranty window, hey?
https://www.tesla.com/support/8gb-emmc-recall-frequently-ask...
My guess is that their "RAM Plus" feature (aka swap) combined with the memory hungry modern android apps turned out to be a nasty timebomb. Which has or still is bricking millions of smartphones after a few years of usage.
The underlying flash memory is trash and the controller already does a ton of heavy lifting to keep the data coherent.
Great, right?
The local carrier dealer lied and said the unit wasn't under warranty. They lied again when reminded of the class-action settlement, claiming only part were included and said would cost a fortune in labor.
When I called Carrier and told them what their factory authorized gold/preferred/whatever-they're-called dealer was pulling, Carrier confirmed I was correct and even verified the unit's serial number and said that if the dealer had checked the SN, they would have found it was covered.
The dealer then said 'fine, but those parts are going to take weeks to get from the warehouse' knowing damn well I had no heat, in the winter. They had us over a barrel and they fucking knew it, and I didn't have any way to prove that claim wrong.
At the end of the day, I could probably buy an aftermarket fan off the Internet and install it myself, spending far less than the certified technician would charge to install the "free" OEM replacement part.
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I had a Phillips 4K LED TV I purchased on sale in April 2021. The TV was glitchy, and I'd get all sorts of weird problems with it - but nothing really terrible.
Then two weeks into January this year, the picture suddenly becomes a jumbled mess of vertical stripes. One second it's fine, the next second it's broken.
Luckily we have a general 5 year warranty period here in Norway, and TVs are expected to last for at least 5 years. I called the shop, and they told me to just bring the TV.
When I get there with the TV, I notice two other identical TVs. I check out the note that hangs on them, and see that they are broken, with the same symptoms as mine. Both had purchase dates around March / April 2021.
I can only assume some component failure.
Isn't that the point of the warranty? They tell you they think the product will last for X years, and then it lasts about X years, just like they warranted.
Honestly, I think something needs to be done so that companies are held liable for expensive products failing and needing expensive repairs after a year or two.
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It will most likely be "How do we restrict this hack" and will eventually get into more restricted/quirky hardware & software.
It would be interesting if someone already in AC repair made it part of their business though. That's when you'd see the teeth come out.
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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!
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.
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). 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.
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
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!
Perhaps someone has already made a home assistant plugin that does this?
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.
You don't need the same model number as the original cap, it just has to have the same voltage rating, capacitance, and number of terminals. You might have to get creative with the mounting solution if the new cap is different than the old one in terms of shape or size.
Also, pro-tip: when you replace a the cap in the outside unit, install it upside-down so that water doesn't pool on top of the cap and rust it out from the top.
I have a gas furnace and I also keep a spare ignitor handy. It's not a matter of "if" those go bad, it's "when."
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?
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/
Run caps: https://www.mcmaster.com/products/run-capacitors/
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.
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!
Simple YouTube video to unscrew the thing, sand off the crud and back in action.
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.
So he unscrews the panel, pulls off the leads, puts in the new capacitor and voila. Then the guy says basically exactly what the above para starting with "A capacitor issue...", including hosing down the coils.
So in 10 minutes I learned another mandatory skill on a Sunday morning, and it only cost $675. (Yes I know better than to place my tongue across the capacitor connectors)
Last year I fixed the condensate drain line clog myself, by uh, well, I was in a hurry, blowing into the pretty grotty drain line. I did purchase the exact model pump for a spare.
I still need to buy a spare capacitor though!
My local HVAC supplier doesn't sell to non-licensed people. I think they don't like dealing with returns from people who don't know what they're doing. I needed a 24vac transformer once. My dad used the same HVAC company for his office for a long time, they still remembered him, and had the part I needed in stock.
My brother's capacitor went out, but we found the part he needed at a local Grainger branch. https://www.grainger.com/category/motors/motor-capacitors
Two summers ago my AC didn't sound right. IIRC the outside unit was clicking on and off. I pulled the breaker. Eventually I decided the problem was with the contactor (a switch controlled by 24vac). I took pictures of where the wires were connected and pulled the contactor. For no particular reason I started taking the old contactor apart, and found a cricket in the middle. I removed the bug, cleaned out the cricket residue, put the contactor back together, and returned it to the outside unit. My AC system resumed working perfectly. https://en.wikipedia.org/wiki/Contactor
Now I could take it back for a warranty replacement, which would give me the same defective unit.
As a result of this, I don't even recommend buying components locally any more. The capacitor from amazon cost about $12 and is still working years later.