https://blog.hopefullyuseful.com/blog/advantage-air-ezone-tablet-diy-repair/
Forcing customers to replace an entire system just because the cheapest component failed might be really profitable, I have no idea... But I do know that it annoyed me enough to make me want to fix it myself. While I understand that what I do next is beyond a large number of Advantage Air customers, in my investigation I found that there seems to be only software choices preventing modern tablets from working with older control systems. Adding a simple "system" chooser to their software applications would give solutions to everyone, while the custom POE connector would ensure they still need their hardware.
My family had a new home built in 2019. As part of the build package a large ducted reverse cycle (heatpump) air conditioning system was installed. As it was part of the entire build I am not sure on the specific price of this system but based on other quotes I have seen for a similar sized house I would guess $10k-$12k. The system has two main parts, the actual Daikin airconditioner and an Advantage Air control box in attic that opens the vents to the various zones. This control system is operated by a cheap POE powered Android tablet on the wall of the living room.
[...] E-Zone running perfectly on an ancient Samsung Galaxy Tab 4. I was elated. After I gave up on repairing the original, getting this tablet working took only a few hours and was a hell of a lot of fun. This tablet is 10+ years old and yet still is much snappier than the junk that came with the system, but if I want to upgrade to something more powerful, say to control my homeassistant etc... all I need to do is plug it into the usb. But for turning the AC on and off it is more than enough and I am currently waiting on a nice flush connector to arrive then will mount it on the wall.
He had to spend an interesting few hours fixing it but it makes a good read...
(Score: 4, Touché) by chucky on Saturday August 31, @08:12AM (5 children)
This exactly is the reason why I don’t want anything ‘smart’ at home. I make living in IT. Dentists don’t fix their dog’s teeth after work.
(Score: 5, Insightful) by Rosco P. Coltrane on Saturday August 31, @08:59AM (4 children)
I have a smart home: it has regular light switches and dumb remote controls and I do the smarts.
I've been on this dirtball for decades and for some reason, I've never found this to be a problem that needed fixing. Even now that I have a disability and I don't always find it very convenient to get up and walk up to whatever needs turning on or off. I still don't understand what problem "smart homes" have been aiming to solve exactly ever since the concept first appeared.
The only two things I might understand need extra smarts is turning up the heater in my house before I get back home from work - for extra, not-strictly-necessary comfort - and starting the car remotely on the parking lot from my office when it's really cold outside.
I can do the latter with a dumb radio controlled starter, and I don't do the former because I don't really mind all that much waiting for 10 minutes to kick the chill out of the house when I get home, But I could do it easily with some cheap arrangement that doesn't require buying an instantly-brickable IoT device for beaucoup bucks and being put under surveillance by the nasty tech company making said IoT device.
(Score: 3, Informative) by RS3 on Saturday August 31, @12:51PM
I've used X10 in many scenarios, helped others set it up, etc, but haven't yet done it in my own home. Most normal light switches, etc., work just fine for me. But when I go off to work there are several things I like to turn off, and having 1 control switch would save some steps, and make it easier- fewer things to remember to do. It could even be run on a timer / schedule. Anyway, X10 might be interesting for your situation.
(Score: 3, Insightful) by SomeGuy on Saturday August 31, @01:51PM
This is what people don't understand when I tell them I don't own a smartphone, or whatever fancy smart garbage. There is always a cost-benefit, and the cost - upfront, long term, and time consumed costs - that does not justify the costs for me.
Some trivial little ability might be nice or convenient to have, but I'm not going to spend lots of money, waste my time configuring, updating, and constantly re-learning some gadget, and then have to spend money on a new one because of a short artificial life span, just to do that.
But everyone else just goes and throws money stuff because the TV told them to.
(Score: 2) by krishnoid on Saturday August 31, @05:02PM
I didn't expect to keep reposting this Galactica clip [youtu.be], and I never expected it to be so perfectly applicable in so many situations. Or maybe it's just the single "IoT" situation, in recurring scenarios.
(Score: 2) by owl on Saturday August 31, @07:36PM
Bragging rights to guests/buddies when you can remotely turn on/off everything at home.
If one is not competing in that competition, then one sees that there's little additional real benefit.
If your "get home from work" time is usually the same day to day, a simple "timer thermostat" where you can set it to "turn up" at 5:45pm for your likely arrival at 6pm would do the job just fine, and won't suddenly stop working next week when the company retires that model and turns off the internet servers it talks to for no good reason other than to shut down and force another sale of the newer model.
(Score: 5, Interesting) by Revek on Saturday August 31, @10:57AM (5 children)
Daikin makes good hvac units. We have four in our building. They are not our problem. They are all controlled by a tridium jace 8000 controller. Its a piece of junk. A under powered unit running linux. Whats worse is they sold us a used controller when they installed it. Even worse this supposedly open framework requires huge monthly fees for the software necessary to fix the most basic things. When they put in the used unit they didn't update the self signed ssl certificate. It expired quickly after installation. You can't install a new certificate without the programming software. We have had the only company in the state that is licenced by tridium come in a few times but the people they send lack the skills necessary to follow a youtube video on how to replace the certificate. This has broke the ability of the unit to connect with any mail server other than a insecure mail server. The last time they did work for us they charged us $15,000 to replace ten contactors in the VAV's. The materials were less than a 1000 dollars. As you can imagine we don't call them often.
The frontend we have to work with is poorly designed not even following the guidelines that the videos available suggest. Its all xml configs that I can edit and I've managed to add hyperlinks that make moving through it quicker and easier. Unfortunately every time they come in and work on it they write over my changes. Even if I manged to purchase the software which they are unwilling to do. I would have to start from scratch without the project file that they built the original fronted with. Its maddening that I could easily fix my problems but am prevented by a proprietary system masquerading as open framework.
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(Score: 2) by RS3 on Saturday August 31, @12:41PM (3 children)
This is interesting on many levels. Firstly, next time you need the contactors replaced, contact me. I'll do them for $12,000, and give you better ones that'll last longer. I'll be sure they have good arc quenchers. I might even add some "soft starts" that'll reduce the surge. :)
Not sure if the software you're referring to might fall under the "SCADA" name, but I've done some of that too, including some open-source SCADA. Yes, one of the big problems with open-source is that anyone can grab it, custom / proprietary modify it, and/or add their own apps / drivers / libraries / whatever, and you're stuck. Big example is VMWare. Probably hundreds of other examples.
I hadn't heard of the "Jace" things but a quick search is very interesting. ARM CPU, etc. There's probably a serial port on the thing that you could log into with simple serial port terminal software. (I forget the names of the many I've used over the years- MiniCom? Been using putty for years). It might not be super difficult to find that port. ... Yup, quick websearch results in many "Jace" "serial port" hits, including that it's probably RS-485 but that's easy.
I don't know, haven't done much research, so I'm just guessing, but if my hunch is correct that the Jace is running some kind of SCADA system, you can pretty easily set up a PC to be the SCADA master in the system, running open-SCADA or something else. There are so many. You'd need to know the controllers at the units and the SCADA would need the "drivers" for those units.
(Score: 2) by Revek on Saturday August 31, @03:56PM (2 children)
The same situation has already reoccurred and I replaced them. We also installed a circuit breaker that trips when the voltage drops too low. So its unlikely to reoccur.
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(Score: 2) by RS3 on Saturday August 31, @04:52PM (1 child)
Oh good. Yeah, you can get "bigger" contactors- higher current rating. Again, make sure they have "arc quenchers" in them if the compressors are big. I'm not sure the size when you want the quenchers, but maybe over 5 hp or so.
Last place I worked (food processing) we had a 6 compressor chiller. Each was 60 HP IIRC. Even with arc quenchers a couple of them melted down. Literally a small pool of copper below it. Had to have been quite a bad arc happening. I wanted to upsize the contactors but got overruled (idiot politics).
Not sure if your compressors are 3-phase, but if so, you can get contactors with built-in phase-drop protection- they'll open fully if a phase drops (which will quickly fry a big motor). I may more be thinking of big circuit breakers with the phase drop protection. Also you can buy separate phase-drop protectors, as well as a "soft-start".
(Score: 3, Informative) by Revek on Sunday September 01, @04:21AM
These contactors are in the vav's. Each KMC vav has a 440v feed. They drive the heating elements in each one of them. Two times now during a storm we have had dozens of power drops in a the space of a few minutes. The resulting condition burns out the contactors. The low voltage (24v) coils are what burns out in them.
The Daikin units have few problems. The most annoying one was the circuit breakers for the evaporator fans. We had one unit that the fans never tripped and three who they tripped out constantly in hot weather. I had a very hard time getting them to address the problem since they always blamed it on dirty coils. Finally one day they sent out someone with a clue who discovered the circuit breakers were set to 1.5 amps in the three units and 2.5 amps in the one that never had a problem. That only took two years.
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(Score: 2) by krishnoid on Saturday August 31, @03:25PM
Hmm ... air conditioning, McFlurry machines ... I bet this is how Mr. Freeze made all his pre-origin supervillain money.
(Score: 5, Interesting) by RS3 on Saturday August 31, @01:26PM (7 children)
Being a lifelong tinkerer and repairer, I'm forever fixing things. No, replacing an ailing car is not fixing it. To mine and many others' chagrin things are more and more difficult and expensive to repair. For a very long time there's been a paradigm of modularity, and replacing modules was supposedly easier and cheaper.
In the late 80s while at uni I worked part-time in a repair shop. TVs were much of the work. There were brands that were built with fairly easily replaced modules. Well, those modules turned out to be very expensive for the customer, and I didn't get paid much to replace them. I decided I made more $ by fixing the module since I had already diagnosed the problem and its location, and saved the customer $.
A recent and somewhat infuriating example, and there are many, in my current main car- '06 Volvo. It started saying "Passenger Door Open" on the dash, and the interior lights would stay on (eventually the computer turns them off). Being relentless, I tore into the door, very long difficult tedious process to extract the door latch mechanism / module, including that you must remove the door glass. Inside of the module is a very small micro-switch. It's all potted in with something- silicone maybe. Whittling away at it, finally exposing the switch and flexible circuit it's soldered to.
That door latch module is hundreds of $. Even used ones on ebay are like $50-100, and there's no guarantee they won't fail soon.
Turned out to be two problems, and required two or three door disassembles: in one case the flexible circuit developed a fracture. Soldered in a jumper.
But the deeper problem was that the switch developed some tarnish on the contacts and wasn't quite making contact. The switch was much too glued in to extract and replace it. An xacto knife and some patient surgery, I removed some of the side of the switch, carefully burnished the contacts, put in a tiny dab of silicone grease, taped over the new side port, and it's still working almost a year later.
There's a better fix: switch contacts will develop tarnish. Many switches, certainly my Volvo's door lock internal switches, are connected to an input on a small microcontroller. There's negligible current passing through the contacts- not enough to burn off the tarnish, so it builds up until the switch contacts have high resistance and there's no signal from an otherwise working mechanism.
A simple fix is to intentionally cause some current to pass through the switch. There's a term for that and it escapes me. A very simple way to do it is to install a capacitor across the contacts. Capacitor will pass no current when the switch is open, but will hold a charge. When the switch closes, the cap will discharge through the switch and voila, clean contacts.
Not sure what said cap needs to be, maybe 0.1 uF, or 1 uF or so. Doesn't need much, and too much uF might cause a big delay in the microprocessor seeing the switch opening- the very tiny bias current will mean the cap will take some time to charge, so the circuit won't see the open switch until the cap charges enough. I'll experiment sometime. Simple enough to measure the switch bias current and calculate a reasonable cap value, whenever the switch or another one acts up.
Great article, enjoyed the read and inspiration, thanks.
(Score: 5, Informative) by fraxinus-tree on Saturday August 31, @02:16PM (3 children)
The term that you think of is "wetting current": https://en.wikipedia.org/wiki/Wetting_current [wikipedia.org]
(Score: 3, Insightful) by RS3 on Saturday August 31, @03:40PM
Yes, thank you.
(Score: 3, Informative) by RS3 on Saturday August 31, @05:00PM (1 child)
Read that WiKi some more- interesting why they call it "wetting"- due to keeping some small current running through various systems to ward off disconnects in wire junctions due to corrosion. Sort of keeps the wires wetted to each other.
I wonder if that's one of the reasons for keeping 4 mA flowing in a 4-20 mA current loop system. The other reason being that anything below 4 mA is considered a fault.
(Score: 3, Informative) by fraxinus-tree on Saturday August 31, @07:49PM
Wetting current is in fact needed even in contacts that are not normally switched, e.g. in a pair of twisted wires. On the other hand, 4-20mA (and its 3-15psi grandfather) is about the dynamic range. 1:5 is a good dynamic range for a simple circuit or a mechanism. Zero in a lot of places is pretty ill-defined.
(Score: 0) by Anonymous Coward on Sunday September 01, @02:14AM (1 child)
> There's negligible current passing through the contacts- not enough to burn off the tarnish, so it builds up until the switch contacts have high resistance and there's no signal from an otherwise working mechanism.
I'm into fixing things, but perhaps not quite with your fearlessness...
This reminded me of a side-by-side fridge that lost the LED light in the freezer compartment, just out of warranty. While chasing down the problem I discovered that the door switch that turns on the lights was switching 115VAC, basically the door switch was turning on the power supply that ran the LED module on low DC voltage. At first I was surprised, but then a little research suggested that switching AC is a good way to keep switch contacts clean.
Perhaps this fridge did have some sensible designers? Or perhaps they kept the wiring harness and switches that used to turn on an incandescent bulb for the freezer light...
As it turned out the LED module (4 surface mount LEDs on a little board) was the problem. Hunting on eBay the replacement part was still well over $100 (much more from official parts suppliers). I bought a meter of LEDs on a tape and wired them up to the connector for the module. Used some wire ties to hold them on the bottom of the fridge shelves and they are working fine ~10 years later.
(Score: 2) by RS3 on Monday September 02, @01:58PM
That's an awesome fix! Kudos! You probably got much better light distribution too. That's going into my memory banks. I've installed some LED strip lighting here and there. Very (too) often people get into the "exact replacement" mentality, and I'm all for improving something, if possible, as part of a repair.
I'm speculating one factor in the 120V switching decision: you could switch the low voltage side and still have contact-cleaning current, but the power supply would be always on, is most likely a switch-mode module, and the capacitors would have expired before the warranty period. Come to think of it, having a PS always on would slightly reduce the EPA efficiency rating, maybe negligibly though- I dunno...
As I've written several times before here, my observation is that many LED light system designers decide to push the LEDs to their current (amps) limit, and of course they don't last long- certainly not the ~20 years people like to talk about.
IIRC every failed LED lamp system / bulb that I've opened up (more than two dozen) has failed because an LED (the actual diode) has failed in the chain. Some have burnt / blackened. (usually due to a weakening of the thermal bond between the LED and its substrate, which gets worse and worse as the heat further damages the substrate / bonding agent, LED gets hotter and hotter and eventually flames)
(Score: 3, Interesting) by sjames on Monday September 02, @08:47AM
That sounds like how I kept the old stove going for an extra 10 years, complete with using silver solder to build up pitted contacts.
My current coffee maker is hot-wired, everything bypassed but the thermostat, thermal fuse, and heating element. Plug in to turn on.
(Score: 3, Interesting) by SomeGuy on Saturday August 31, @01:37PM (3 children)
Just a little tip, if there is refrigerant leak, never EVER let them add refrigerant unless they are going to do a complete pressure test right that moment. That is money literally out the window.
Personally, I'm regretting getting rid of my mercury switch thermostat. AC salesmen will force you to get an invasive "smart" thermostat, and then screw you over if you make them give you a more reliable, simpler one.
(Score: 3, Interesting) by RS3 on Saturday August 31, @05:09PM
I'm not sure if you can still buy a mercury switch thermostat, maybe used? But you can certainly buy non-smart thermostats and they're pretty simple to install. Well, okay, HVAC wire colors and functions can be pretty crazy, so it all depends on how complex your system is as to how "simple" it would be to install a "dumb" thermostat. But it can be done. I still have mercury switch thermostats in my house and several spares. They work perfectly. They don't try to track my habits, they don't try to outsmart me, and I'm fine with them. :)
A few days ago I read about a survey of car owners and a large majority don't like and don't want all the crazy automated stuff. Some things like parking assist, auto parking, lane minding, etc., seem like good ideas, but those things also dumb down the drivers, which is something we don't need. Also add very complex and even more expensive repair bills.
(Score: 3, Informative) by epitaxial on Sunday September 01, @01:02AM (1 child)
Several years ago I did buy a simple programmable thermostat and it was a worthwhile purchase. Winter mornings the house is already warmed up a bit by the time I'm getting out of bed and then later on when my wife is doing her daily exercise routine it lowers the temp for her. No way I'm ever getting one more complex than that.
(Score: 2, Interesting) by Anonymous Coward on Sunday September 01, @02:28AM
When we had our house A/C replaced about 10 years ago the contractor gave us a Honeywell programmable thermostat and the damn thing couldn't be programmed--maybe we got one partly broken? We followed the detailed instructions several times and it never worked as advertised. We normally don't have problems programming other things like the microwave clock, etc...and both of us tried independently so I don't think we were the problem.
Anyway, I discovered that the same form factor was available in a non-programmable version, bought one of those and we've been fine ever since. It does have a useful feature, it's possible to change the dead band (hysteresis) over a small range. As delivered it attempted to maintain tight control on the house temp, which meant turning the A/C on and off frequently. We're not that picky and I'd rather have less motor starts and potentially longer motor-starter lifetime, so changed to a wider deadband.
The A/C installers offered to combine the new thermostat with the house heat (gas, hot water boiler & baseboard), but I declined. I'm very happy with the ancient mercury switch White-Rogers
thermostats that came with the house, don't need batteries, and just keep on working.
We both work from home and have irregular sleep schedules, manually doing the day/night control is fine by us.
(Score: 2) by sjames on Monday September 02, @07:05AM