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This video is brought to you by Sportlin. Quality, Integrity and tradition. We've got a trained package unit here today and the customer says that the unit's making a thumping sound. They said that it just like turns on and turns off.
That's weird. The heater's turning on. Why would the heater? It's very odd. So they said it's just making this constant thumping sound.
Let's see if we see anything. I Told them someone messed up and took the drain line and put a cap on it and down in the downstairs. Oh, you hear that? It's like the blower motor turns on and off. Um.
I Told them to fix this years ago. They still haven't fixed it. All right. So indoor blower motor is not running okay.
Filters look decent. Look like they haven't ran in a while. Interesting. Oh, we got a plugged up drain.
That's one thing difference. It's like starting and then stopping. That's weird. See if this guy drains, there's like something stuck in this drain pan.
There we go. Really weird, huh? They're getting like a control issue or something. Something's going on here. So let's open this up.
Let's start by checking voltage and seeing if we're getting a call for what we're getting a call for from the thermostat now. I'm suspecting that there's something going on with the art with the board right here. because let's go ahead and test voltage. It's like just intermittently turning things on.
So let's go ahead and go Common to R 25 volts. Okay, so let's go ahead and go Common to G 25 volts and we're not calling at the moment. Let's just watch it see if it'll cycle. Nothing's changing about my call for cooling.
Nothing. Okay, um, let's go ahead and go to I Believe this is the indoor blower motor contactor right here and we've got no voltage. Let's wait for it to cycle. It's a 24 volt contactor, so let's see.
now. it's not going to restart. We're getting a flash like error code on there. one, two, two flashes and then off.
two quick flashes and then off. I'll have to look at the instructions to see what that means. I'm waiting for this thing to try to start again. It's weird though because it like tries to start the inducer too for the heater.
It's really odd. Come on buddy, you could do it. Put you back into it. Let's see, this guy does anything again.
I'm gonna try to wiggle see if maybe we got a bad connection or something. nothing I forgot. like a bad solder point or something. Something's going on with that board because we've got 24 volts going into the board and it's not engaging.
what the heck is going on? It gets voltage to the contactor quickly and then disengages it. It says that when it flashes two flashes it means Diagnostics exist, but it's interesting. When it turns on, it goes solid. So it's flashing like there's a problem.
and then it turns on and then the light goes solid and then it starts flashing again. So I think there's something wrong with that RTR and board. Um, let me check some other things. Let me make sure we don't have a simultaneous Heating and Cooling coil. I've seen us do some weird stuff before I Confirmed we do not have like a simultaneous Heating and Cooling call I disconnected the the heating wires just for Giggles What I'm going to do is put it into test mode now and see if we can function in test mode. So I'm going to jump out the jumpers I Don't know if it's going to go into test mode. Yeah, it's not gonna. Doesn't seem like it's gonna go into test mode.
Foreign? Yeah, it's just doing a weird like boot mode or something. All right. So what we're going to do is we are going to cycle power, give it a second, turn it back on, should probably pull that board out well before I go and get a new board even if I can find one. I Need to call, but we'll turn it on.
Okay, so we have got a solid LED Now that's odd. It's solid. Now let's see if we get a call for fan. They did have a lot of lightning storms this week.
Go figure. Now it's running right I Had to power cycle it, Huh? Okay, so now the indoor blower motor is running like it should be. The light is solid, huh? That's very interesting. Let's see it go through a cycle, see if it'll start up.
So that's interesting. So I jumped out the unit I Haven't gotten a call from the thermostat as of yet. I'll look and see, but we got a 54 degree Supply 74 degree return. Both compressors are running, both condenser fan motors are running.
Huh? I wonder what happened here? I'm wondering because we had a lot of, uh, we had a tropical storm come through and we had a lot of lightning and thunder and stuff come through this area and I'm wondering if, uh, if something just happened with this unit I Also blew out that drain. by the way, there's a big old chunker in that drain. Um. I'm gonna let this run for a little bit longer.
That's very interesting, all right. I Went ahead and went down to the thermostat, pulled my jumpers off, went down to the thermostat, gave it a call for cooling from the thermostat to verify the thermostat's working. It is. We don't have a call for second stage yet.
Second stage doesn't pulled in, but we know it's working. We're not getting that flash and there goes second stage. so we're not getting that flashing anymore. It's It's interesting.
Like I Understand if there was a diagnostic, but it was turning on and off. On and off. It doesn't seem like a diagnostic problem to me. I Feel like something happened with the board? I'm wondering if it had to do with the lightning like I said that we had.
So I'm gonna go ahead and probe up. go through the unit, make sure everything's good. Um, four people ask too. We do not have an overflow switch on this so there's not one there at least I don't think there is I'll double check, but there's no overflow switch so that's not causing our problem. All right, let's have a look here at what we got going on. Okay, so first stage. Um, let's go back. Nothing too crazy jumping out at me I don't see any reasons for the unit to go off on a safety super Heats A little bit on the high side, but uh, they don't have insulated suction lines on these things.
I'm not too concerned with that subcoins in line and where I think it should be. This unit has uh, fixed orifice metering device on it. Okay, let's go ahead and jump over to Second Stage see how that one's doing. Second stage is kind of running really similar.
18 degrees sub cooling, 23 degree superheat I don't really see a problem with that. Let's scroll over and look at my temperature split is about 18 degrees. Uh, we're calling for about 20. Okay, that's not too too bad though.
Um, let's look at our delivered capacity: 160 000 BTUs That's a little bit low, but I also have the this is a weird unit um I should probably move my probes around. Uh, as far as the tonnage goes and stuff, it's hard to get it to line up to what we actually should have for this equipment. Um, but I'm not too concerned about the BTUs that delivered BTUs I'm more concerned in the operation of the unit and I don't see anything wrong here. I'm looking for something that would cause the unit to go off on low pressure, high pressure and possibly I don't know what caused it to go into that weird like boot logging mode or something I don't know what that was.
Dude, it was like a boot loop or something. It was stuck and then once I cycled power, it started up. So I'm not seeing anything. so I'm gonna watch it for a little bit longer I just pulled all my probes off I got to get the Caps back on.
but um, so I'm not seeing anything wrong. really with the refrigeration circuit? Uh, the belt's tight, the filters are clean, the evaporator coil looks clean. um I'm gonna go through and just have a look at these contactors. This one has some arcing that has happened inside of it.
like which is normal. Um, you know, but it's not I don't think it's time to replace this contactor. It doesn't look that bad I Can just see some signs of it pulling in and out. but I'm really curious about this one because it was on off on off for I Don't know how long.
so I'm going to keep inspecting all these two. These guys are both perfectly good. This guy is done like it's all burnt in there. So I'm gonna go ahead and change this guy out because uh, we don't want to cause a problem with that.
And you got this. Why you got to be thorough with this stuff? I'm not done yet either. Something that I don't like is these thermostat wires are like all jacked up and there's a crap ton of extra. so I'm gonna go ahead and cut those down too and fix those up all right.
I'm not a fan of stripping the wires down here to jump them out. I'd prefer leaving a little bit of exposed wire sticking out in a way that it's not going to short on anything. and then I leave the red a little bit longer. so I can get two jumpers on there if need be. So then that way one jumper can go to y1, one jumper can go to Y2 that kind of stuff. So um, we got the contactor replaced these wires done I'm not seeing anything else crazy in here. Capacitors look okay. Everything looks good down here.
I need to get the cap still on I Want to open up this electrical section because these are notorious for having loose lugs and burning up the disconnect switches, so we're going to check that next. Don't really see any problems in here. The wires are nice and tight. Everything's good.
Yeah, so everything's looking good in there. We're gonna get this back on and then turn the unit back on. Man, these last couple days have just been exhausting. Been early morning stuff.
Today is Wednesday August 23rd of 2023. So this morning I was up at four yesterday I was up at four just early morning I did a crane job today changing out a package unit yesterday. I don't remember what I did yesterday. Oh I fixed a reaching cooler that I had to be somewhere super early.
Oh man, it's just been exhausting. It really has. um, it's not as hot really? I mean it's like in the 90s we have a little bit higher than normal humidity. I'd say it's probably like 30 or 40 percent.
Um, you know, so we don't really know what humidity is here in Southern California We had a tropical storm go through this last week so the humidity has been higher than usual. But yeah, just been busy so hopefully you guys are doing pretty good all right. Um, so this one was a service call I think it was actually yesterday. uh August 22nd I think I Ran this call, we got a call that there was a constant thumping.
The air conditioner was making noise Now initially I thought it was going to be an exhaust fan issue because they've called saying the HVAC unit's making noise and then it ended up being an exhaust fan. Um, but nope. When I got there, it was one of the air conditioners. It was their dining room.
AC So they only have three ACs on that building. kitchen, dining room, and bar and uh, dining room for some reason was stuck in some sort of boot loop. It was weird. It was just like stuck now.
I Don't think And and you guys enlighten me if you guys have ever seen this problem before, if there. if the unit went off on a diagnostic lockout I believe it's just going to give you the flash code and not run until you restore power or you know, power cycle the unit, then it's going to start up. This one wasn't doing that. This one would say there was Diagnostics present.
then it would stop. the Um. the Rtrm light would go solid like it was normal operation. The contactor would turn on, the heater would occasionally turn on and then it would go back into Diagnostics present. Don't know why I I don't know why I don't know what was going on there. So I was thinking we had a bad circuit board and we very well might still have a bad circuit board. Okay, but once I power cycle the unit, it was working great. So my next step to go through that was to put up probes on the unit, see if there was any reason for it to go off on a lockout.
Low pressure, high pressure anything? Nothing. nothing. Everything seemed fine. Condenser doesn't seem to be a problem.
fan motors are working, everything's good. So I just kind of went to the customer and said here's the deal, let's give it some time see if we have any more problems. I said I will gladly put a new circuit board on here I don't even know if you can get them right now, but I said I'll gladly dig into that and go change a board but I said you know there might just be something weird that had happened because we had that tropical storm go through. We had lightning and all kinds of stuff power issues I think it was just something with that.
time will tell I did my best. Um, cleared that drain too. Uh, did confirm there's no float switches on that unit. Belt was tight.
everything was operating as best as possible. I Don't really see any other issues with this I didn't hear from them today. You know we'll give it another couple days and and then we'll close that one out. Um, you know you got to be thorough.
Uh, same time. I started thinking that contactor going on and off. On and off. On and off.
The filters were really clean on the unit. I'm sitting here thinking this has probably been happening for a very long time. Okay and then I inspected that contactor also found the contactor. was totally burnt from the on off, on off on off.
it's constantly arcing so went ahead and changed out the contactor, inspected the rest of them, didn't see any problem. so you got to be thorough on this. There's nothing worse than saying oh yeah, let's just keep an eye on it and then that contactor fail, you know, and then that just becomes another service call. So big picture stuff when you're out here doing these calls.
I Really, really appreciate you guys making it to the end of the video. This one was a short one, but I have some good information in it, right? So uh, thank you so very much. If you haven't already, please consider checking out my website Hvacrvideos.com We got merchandise available on there. Great great way to help support the channel.
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Could it be a power surge?
Poor firmware engineering and possible cost-cutting on the PC board
A watchdog timer, both the one provided in the MCU and an external watchdog timer, would have prevented this from happening. Service area Kanata??
Jeeeze America, get some terminal shrouding about your contractors and connections FGS 😮
(I’m a Scottish Ac Refrig tech, worst wiring I ever saw was a Rheem unit from USA in the 90s
Was HORRIBLE wire nuts from new 😳
Never ceases to amaze me how shitty the equipment is installed.
It reminded me of some of the old Carriers boards would flash codes for RF interference. I think it was 8 flashes. They could drive you nuts. I finally decided that they must have put that code in because they couldn't figure it out either.
As an industrial automation engineer. The problem with that unit is low quality firmware. Things like watch dog timers and variable limit checks are essential to good firmware. If anything is outside the expected range the firmware should reset the controller and get you back to a known safe state.
As long as isn't a Humping Sound you wi be good to intrude into this A/C units sound problem ? A/C magic maker for37 years ?
You can also clean contractors with a file, i have to do it all the time at my job. And it fixes it. Saves money also
Former IT guy, static across the board could easily trick the PCB by jumbling a memory area or address. If a cold boot resolved the issue, at least temporarily, then those ROMs just got stuck. But were it me, I'd replace that PCB. Are you in Orleans ?
a quick power blip off/on can mess up stuff sometimes.
A giant EMP pulse generated by a lightning is more than enough to throw off any microcontroller circuitry. But normally a power cycle is enough to fix any weirdness that may have happened. It is pretty unlikely that the board died though, as it was enclosed in a metal enclosure.
Click bait .. lol come on bro fake it or something, I was waiting for a uneven washing machine load sound lol Are you in Barrhaven ?
Hey Chris just saw this video. I had the same issues a few years ago. It turns out the combustion motor was internally shorted and it was causing all of the issues you were seeing. Trane put out a service bulletin about it.
I've seen a lot of electronics go into a loop of crazy after interrupted power supply. Thats all it can be.
Happens.
Its actually a bad design from manufacturer, but nothing is perfect.
Voltage surges, spikes, brownouts, lightning, etc. are bad news for any computer controlled devices. Electroincs are very sensitive to changes in voltage.
Those Reliatel boards can be very finicky when the building has power issues, also I didn’t see if you checked the Frost-stat or fan proving switch(not on all Tranes), as well as the coils of the contactors themselves. I’ve had fan contactor coil that read ok, but the coil got hot after running for 1/2 hour and caused board to act wierd, and “short cycle”. Almost exactly what was going on in this video. Btw if you have issues getting a hold of a “new” RTRM board, the older versions of them work with the newer units(except Symbio) if your in a pinch and they can’t get a current version board. I keep a used board that is operational on my truck for diagnostic and temporary purposes only, and it has helped a customer get through a hot 14 days before the new one arrived. I know my comments are long but I’m just trying to share knowledge from 1 Tech to another, and hoping my experience helps someone else out of a bind.
Great work, Chris.👍
Those RTRM boards suck, ive seen them have the weirdest failures. I replaced one on an 4 year old Trane, it would intermittently work then stop working. Econ was fine, no other safeties knocking it off. Installed a new board, and havent been back since for it. I like Trane’s residential units, commercial, not so much
In response to the Micro-proc acting like it did, Just like a PC it does need to be rebooted. Having said that, since something happened (the board freaked out) reset is standard. It's a Micro-proc…. From below, I you decide to replace the ICM with the updated version, just remember I replace Ind Draft Assy, HSI, which are not included. The update was intended to utilize a contactor to separate Lo and Hi speeds on the Ind Mtr. Pretty intense on the wiring but do it once it becomes automatic!!!!! My .02 In addition, if you want to go deep and I know you do, lol no pun intended you will find that the hi speed motor winging is shorted to ground, but only thru the other LO speed winding… I know that sounds stupid, but consult Trane if questions. Thanx….
Hello friend, Mike T. from Buffalo, NY: There is an update kit for the trane units using nat. gas as there was an issue with the inducer motor running constantly even w/o a call for heat. Take a look at the upper CB heat controller and you will find that the contacts on the peanut relay are pretty toasty and in fact indicate a short, NOT on the board (But needs replaced) internally due to the way trane used to control the IDM. There is an update kit for this. I only caught it doing what you seen about 15 x but more on the IDM running while walking up to unit, but none the less the issue will come back. New update kit comes with 2p30a24v contactor all wiring modifications and circuit board. You need to order the IDM separately as it does not come w/ the kit. I will have a pt# Tuesday or so…… My .02 MPT… The reason I say this is as you walked up on the unit I heard the IDM running…..
Question. Did the contacter fail because of the fault? or did the fault cause the contacter to fail? which way round is it?
I can’t tell you how many times I’ve had to cycle power to unflake RTRM boards. I think that they’re especially sensitive to static electricity. I always use caution to not rush out of there quickly though. Callbacks are teh debil
Edit to say: Greater Cincinnati commercial/Industrial tech of 20+ years Service area Barrhaven??
Those older trane unit don’t like lighting storms I do medical rooftop units and we had a lot of older Trane units at one point that if we had thunderstorms we were getting called out the next day for RTU not running it was weird but nobody could explain it. We will reset it change contactor if needed and it will go back to normal RUN FINE till next storm we put on a phase monitor only saw spike during storm We actually had a building that had two units, one older and one newer anytime a thunderstorm happened. The old one would always go down. The new one would never have an issue. Weird.
I have had the flame sense rod do that if it was wet or rusty. It senses the short to ground, maybe thinks its a flame, and brings on the inducer and blower. But i don't think a power cycle would not have fixed that.
not sure about those units, but i've seen high limit thermostats cause similar issues, limits near burner, blower housing, mid heat exchanger. the vibration of blowers/compressors starting would cause them to chatter and kept making the board go into a restart loop, thinking it was "overheating". they looked ok on visual inspection, but a meter across them catching peaks would show or a graphing storage scope!. Are you in Nepean ?
Had a similar issue with another Trane unit. Arrived with the unit locked out on diagnostic but then would attempt to startup and enter immediately into heating mode. No call from the thermostat for anything. The weirdest part, I was able to power cycle the unit and he problem would go away, until the ever 5th cycle where the issue would rise once again. Turned out to be just a bad RTRM board. Lots of electrical storms in my area, so it follows.
I’ve seen many times that contactors do that when their starting to go bad. Mostly see them a lot in residential when there’s a short on the Y call and it cycles over and thermostat gets delays. Contactors have a shunt on the coils. Good video Chris 👍
Chris, do you not have a TD-5 Tool?
Electronics acting up, classic 😅😅
Your Customers Appreciate your Early Hours and your Willingness to Help them get their HVAC Services Restored during this Extreme 🥵 Heat. Thanks! 👍🙏
In the MCU hacking community, one technique that is used is injecting a noisy or dirty power supply to get the micro into an unstable state that allows us a back door into an otherwise secured device.
Given the hurricane remnants that passed through, I agree with your guess that lightning or potentially bad utility power put the micro into a funky state and just needed a reboot.
p & N junctions can build up a capacitance and thus fail to function. Once you remove power, and the filter caps discharge, then the junctions clear, responds normally. A lighting strike can and will cause p&n junctions to respond abnormally. I'm sure everyone here can attest to their phone or computer needing a reboot from time to time – some of these are due to p&n junction failure.
Had the same type of thing happen on a residential furnace and a/c. Only been at it 5 years but I’ve only had that one do that to me. It was right after a good storm and it worked temporarily when you cycled power.
Electronics guy here that also do some programmation on microcontrollers.
Microcontrollers tend to be sensitive on power issues. The reset circuit is not ideal on most microcontrollers, and it is not common to add external ones. Even with external ones you can still have issues.
The problem can arise when there is a power issue that cause memory corruption OR literally glitch the hardware. The reset circuit should have prevented it by holding the microcontroller on reset state, but, due to many reasons, that reset often don't work well.
One reason why is that the faster that the microcontroller run at, the higher the minimum voltage is. There is a "brown out detector" on many chips, but it may be set too low, or be too slow to react. There is also some edge cases, where the microcontroller, due to the instructions it currently run and what it do with the hardware, can draw more current and cause some local dip in voltage inside the chip itself (normal), but time that with an actual just above the threshold brownout event, and now you have a localised brownout, that cause some corrution or weird hardware issues.
Another thing: there is a few types of reset: power on reset, brownout reset, software reset, watchdog reset are some common ones. Not all reset does reset everything. Software and watchdog reset might simply reset the program counter and disable the interrupts. Basically, it just do a "jump to the first instruction of the code" with very little hardware reset, leaving most of the hardware untouched and possibly in unstable condition. After all, software reset mean that the programmer want to restart the program, so it assume that the hardware is fine. The watchdog is more in case of a software bug, where the programmer forgot to add an exit condition in a loop for example. The hardware should still be fine. The software is expected to reset everything as needed.
Brownout will reset more, but still assume that the hardware should have survived and is in a stable state.
Poweron assume that everything lost power, so most self-resetted. It will reset almost everything, but if the hardware is in a true unstable state and no hard reset lines goes to that section, then the hardware stay locked up. Which then can cause the watchdog to trip because the code freeze trying to access that hardware…
And yes, it's a royal pain to debug such issues.
When developping stuff on breadboard, you can get such weird issues easilly. Microcontrollers that use a few milliamps can instantly draw over an amp for a tiny fraction of a split second, enough to do the local brownout, all that because you used a bit too much wires and not quite enough capacitors… Issues that normally goes away on a true board (you don't have all those wires, but direct traces, and also the wires ain't barelly connected, but everthing is strongly connected via solders). Are you in Kanata ?
ITS THE STORM AND ALL THE STATIC . THAT CAN UPSET THE MICROPROCESSOR. WHEN ITS STARTS UP PROPERLY ARFTER SWITCHING OF AND THEN BACK ON . ITS MOST LIGHTLY THAT .
Work on theses TRANE Voyager 2 unit, have found the combustion blower motor running all the time due to a miss wiring I believe, Trane tech Support recommended to install a relay. Originally the motor is permanently powered from the transformer Y1-Y2 (208V). Hope this is useful at some point. Good luck with it.
Nothing stops a Trane. Except a tropical storm. 😂 Service area Orleans??
This is a typical a software instability caused by hardware factors. Lightning definitely could cause a power brownout and possibly a RAM contents corruption. This is why you saw the weird behavior. In an ideal world, the software should detect those conditions and do automatic reboots to clear such errors out. But not all software is able to do that, unfortunately. It takes some efforts to create fault-tolerant firmware, and not all producers are up to the bar.
Trane Reliatel controls are absolute garbage. I've seen nothing but constant problems with them. Truth be told, Symbio isn't much better. Personally, I'm not a fan of trane
Just like on Monday morings!
I've seen many boards soft lock on quick power flashes. This is on residential appliances. Communication is halted until proper power cycle.
Its called processor over stack if you want the electronic term. Lightning and power surges can easily cause this.
Could have been intermittent stuck in a test mode. I have three of the same unit’s and a lot of dust / webs and dirt get on the test screws. IDK but that was unique
It could have been stuck when power went out. So basically it's going to run a normal cycle and power shuts it down when the unit is starting up. So it thinks it's starting but then says hold on im not throws it's self into dignostics. Which would make sense that when you reset it it cleared it up.
We have had so many things malfunction after a handful of lightning heavy storms, and the only fix was replacement in a few cases. This includes set-top tv boxes, optical network terminals, and washer/dryer. One time we even had a lightning initiated surge arc the AC's breaker in the panel to the point where it caught fire from the hot plastic behind the breaker. I am no expert on electrical or HVAC, but I would maybe inquire if the units are bonded/grounded, and have an electrician check for signs of surge arc in the breakers behind things etc. Massive red flags from my layperson perspective. Also, why do so many places let their drain pans collect gunk like that? Mosquito breeding ground and who knows what kinda sketchy microbes growing in there – yuck!
Did you check the error code?
Did you check for insects or debris beneath the board?
I do A LOT of work on Trane Precedent and Voyager. Went to Clarksville last year for the training too. And I’ve never seen that happen before. The only thing I could think of is 1) condensate overflow switch (which you said there wasn’t one) or failing proof of flow switch, both of which are options and are on the RTOM. Another possibility could be poor connection between RTRM and ECM, and it’s messing with the MODBus. Probably the right call to monitor before jumping at replacing the RTRM. Anyway, thanks for sharing. That’s definitely a head scratcher.
I've seen this before but was on a huge sub arc welder. Combo of blackout and static make it so a bootloop. Weird but reset and works fine Service area Nepean??
Chips❤ you got to love them they control zillions of devices. A control board is basically a computer that monitors an controls .. lighting an static discharges do an will affect a board until energy is removed an allowed to deplete. An when re energized the proper flow an directions are re established. A programed chip can become locked due to overload .. Is the board defective? Not necessarily once the chip can clear an go back to it’s normal state of working it can run indefinitely.. I would of liked to see the back of the board for tell tale signs but in my experience the problem lied within the chip. 🤷🏻♂️ as to replacing the board it’s a roll of the dice 🎲 99% of the time if it’s a board issue it will show it’s face in 2 to 3 days .. Service area Ottawa??
I started out as a maintenance technician but after your videos more and more, you inspire me to pursue more in life, thanks man here are your flowers 🌹🌸💐🌺🌷🌻🥀🌼
Computer tech here, and I used see this all the time with networking devices. anytime there a a brown out where the power drops low then comes back up and even a quick power out less then a second or 2. Not enough time for all the capacitors to drain. There's a reason most IT guys ask if you tried turning it off and on again. In extreme cases you need to totally drain power from the device. I used to work for a Internet support for a province in Canada and every time after a thunderstorm computer network cards would go into a unknown state where they couldnt see anything connected to the port. Shutting down the computer or restarting would not fix it and the only way was to turn off the power supply to the computer off for a good 10 seconds so the all the caps would drain then turn on the power back on.
Maybe there is a firmware update that the board needs
Most likely it will be fine, until it isn't. Glad to see you made it through the hurricane in one piece! See you in the next one.
Gut feeling here is a brownout or whatever causes some parts of the circuit to reboot while others did not. Resulting in corrupted data and thus the weird behavior.
I appreciate the fact that you didn’t cycle the unit before digging deeper. Some restaurant managers will bounce their ice machines once they find out that flipping the power clears the incessant beeping sound. Good call on the lightning. CPUs use lots of timed interrupts in the programming of the microcontrollers and an unexpected interrupt from a high voltage spike will send the unit into a tizzy. I couldn’t tell for sure because of monitor resolution; but, it looks like that electrolytic pooped itself during the HVE. That said, you may end up changing that board later, anyway. As usual, thanks for letting us know your thinking process as you take these calls. Keep ‘em coming!
That happened to me, the unit had the peeled thermostat wires to jump it aswell, static was sending voltage intermittently to the blower motor contactor
Transient voltages from surges or brownouts or blackouts can cause some really weird issues with low voltage circuits. If possible I would try and add a surge protector and automatic voltage regulator to the wiring feeding the ac units.
To many variables, the power could have went out of sync, wind triggered a System code with power to heat and cooling at same time, or 24 V hit ground for a moment, but not long enough to pop the fuse. The storm was bad and unusual for the area.😢
Ive seen similar thing happen with a brownout on some other equipment before and power cycleing it clears the memory of those small little processors in the board Are you in Ottawa ?
I live in Mississippi, we have not had any rain for the month. Our temperature is 103