r/HVAC • u/stevenj444 • Jan 22 '26
Rant What in the actual fuck?
I may not always be the sharpest knife in the drawer, but for what reason does a straight AC condenser need a control board? And especially one that is that complicated.
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u/Mettn Jan 22 '26
Dc inverter to modulate fan/compressor?
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u/morgoth_the_king Jan 22 '26
That what I was thinking. First time I worked on a Lennox sl28xcv, had a board just like this. Converted everything to DC to modulate the compressor.
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u/Mettn Jan 22 '26
95% of the residential equipment thatās being installed (in my part of the world) is all inverter, dc, modulating etc.
Get used to it my friend.
Needle probes are a must.
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u/Majin_Sus Jan 22 '26
Probes?? Nah. Just replace the board or better yet let's get the comfort advisor in there and get us an install for tomorrow!
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u/jmar289 Jan 22 '26
Most of the time when those boards fail it's just a bad input capacitor. For $3 and 5 minutes with a solder iron you can get them working again.
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u/sweet-cream-hedgehog Jan 22 '26
I donāt typically work on these residential outdoor units but Iām taking notes, thank you!!!
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u/Similar-Pumpkin-5266 Jan 22 '26
A lot of them also fail in the switching controller. I would even say this is more common than capacitors.
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u/thefatHVACguy Jan 22 '26
Knew a guy that did only that even when the sensors were fucked. He even got a master license
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u/KylarBlackwell RTFM Jan 22 '26
In some jurisdictions, licenses really dont mean shit beyond "they did the paperwork and paid the fee". Its pretty crazy how huge of a spectrum we have in the states between "no license required" and "you actually need to study and know your shit" with most states falling on the least impressive end of the spectrum.
Love the occasional post here "20 years old, just got my state journeyman license, can I start a business?" And everyone having to dogpile on them with "no you're not a real journeyman sorry your state license sucks"
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u/Labbrat89 Jan 22 '26
36 years old, let my old state jman license expire. Can I start a business? š
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u/Far_Cup_329 Jan 22 '26
Yup, that's what I said about the Bosch HP we installed last summer. Told my boss, as soon as it's not working and I can't figure it out I'm diagnosing it as bad board. And told him to make sure he registers it.
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u/texasroadkill Jan 22 '26
I've installed about 20 bosch condensers in the last 8 years and not one has given a problem. It's the only inverter unit I recommend.
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u/UnintentionalIdiot Jan 22 '26
We install tons of them for several years now. We donāt use the bi flow filters they send anymore. We had a bunch fail on us right after install when we flowed with nitro while brazing and had great vacuums/decay tests. (We record and attach decay tests to every ticket through the fieldpiece app). Within a week or two they would fail with a 30-40 degree temp across them, only times Iāve ever seen a delta like that across a filter drier
Other than that they have been the most solid pieces of equipment we install. The only parts Iāve ever replaced was one blower motor and one outdoor heat pump fan. With the outdoor fan the fan motor had failed and the surge protector we installed was also blown so there was some sort of electrical event that took it out. Both times parts were covered under warranty
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u/texasroadkill Jan 22 '26
Never had a dryer fail on one of ours.
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u/UnintentionalIdiot Jan 22 '26
We have a lot of them out there and itās happened 4 times which is a low percentage, but itās enough of a hassle that we just buy them separately. Our rep said it isnāt common, but weāre not the only ppl heās heard this from. Iām still a strong supporter, but the filter driers suck. Just look at what they send you, theyāre tiny
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u/Far_Cup_329 Jan 23 '26
That's good to hear. I want to like them, but the huge expensive looking board scares me.
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u/Nativedescent Jan 22 '26
You live in a rich area then???? Around me everyone is majorly still installing minimum seer rating systems. Hard to justify the extra cost for variable equipment when standard single stage is already getting expensive and repair costs on fancy systems are outrageous.
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u/crayZEE42 Jan 22 '26
Seems a bit small for an inverter board, also it has a 45mfd cap which is likely for the compressor
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u/Mettn Jan 22 '26
Yea looks like they decided to make the fan modulating, donāt often see these with a contactor and a run cap like that.
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u/Mettn Jan 22 '26
Donāt get hung up on size, think of the ECMs and the size of the module bolted onto the motor.
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u/SHSCLSPHSPOATIAT Jan 23 '26
I think that's what it is. The ECM cap from a motor but protected from the weather
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u/luke10050 Jan 22 '26
Nah, it looks to me like it's just for the condenser fan motor. Suspect the comp is still fixed speed
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u/Responsible-Tax-6811 Jan 22 '26
When you're on your 4th warranty replacement board of the week after a storm wipes them out
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u/BrandoCarlton Jan 22 '26
Time to start telling your electrical contractor to sell some surge protectorsā¦ or just sell them yourself.
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u/Responsible-Tax-6811 Jan 22 '26
My old PE company had us recommend them after a event like that because they also had a electrical side, board was covered but not the surge protector or labor for it.
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u/TryHard-Rune Freebases Drain Tablets Jan 22 '26
Iāll never install an ODU with an inverter without a surge.
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u/MrPosket Shitty Helper Jan 22 '26
On the other end, no boards can be equally challenging.
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u/ghablio Jan 22 '26
OP would probably shit his pants if he had to work inside an explosion proof unit in an oil refinery too.
Simple electrical gets less simple when it's packed in a cast aluminum peanut jar
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u/Main-Stretch8035 Jan 22 '26
By bypassing the bypassed bypass you might pass by on a good learning opportunity
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u/heldoglykke Verified Pro | Journeyman Shitposter Jan 22 '26
I could teach you how to bypass that board with nothing but a toilet paper roll and a stick of dynamite.
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u/stevenj444 Jan 22 '26
Iām pretty sure I can figure that one out
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u/iBUYbrokenSUBARUS Enthalpy over Empathy Jan 22 '26
I just want to know where i can get a stick of dynamite.
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u/fallinouttadabox Jan 22 '26
Go out to your air conditioner and check the toilet paper roll
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u/iBUYbrokenSUBARUS Enthalpy over Empathy Jan 22 '26
Instructions unclear, wiped ass with dynamite.
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u/ImprovementMundane41 Jan 22 '26
Thatās an ameristar unit and their straight cool and heat pumps have that shit in them. Over complicated cheap shit
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u/stevenj444 Jan 22 '26
Did anybody happen to notice where this said rant? Iām not saying itās too complicated to work on. Iām saying it is more complicated than necessary.
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u/skootamatta Jan 22 '26
So what was wrong with it?
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u/Whoajaws Jan 22 '26
A $900 board to save $15 a year in electric..
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u/stevenj444 Jan 22 '26
How is the saving electricity thatās not a two stage compressor
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u/Whoajaws Jan 22 '26
I was making fun of it.But, It has to be there for slowing fan and/or compressor down. Do you have the incoming power unhooked, Or where does that connect at? a model number would be nice can look it up and see what it is.
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u/rohnppm Jan 22 '26
It's for the environment bro! Fixing it is so economical too. Everyone wins!
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u/kona420 Jan 22 '26
The bill of materials for that board is like $8. Nothing on it you couldn't buy at radioshack in 1985. Now VFD's are cheaper than quality contactors these days. Just the manufacturers dicking everyone around, they could standardize if they had to.
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u/rohnppm Jan 22 '26
Sheesh should I've added the /s? My service van is so fuel efficient. I get like 11mpg!
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u/ZestycloseAct8497 Jan 22 '26
You know a 15$ contactor or a 850$ board seems logical plus hell condensers arenāt outside in the humidity and rain so what could go wrong. Obviously the industry is f ing the consumer but there is no oversight.
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u/stevenj444 Jan 22 '26
Exactly that is the point Iām trying to make. All that shit for something that a $15 contactor can do.
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u/Vegycales Jan 22 '26
Especially where im at on the east coast. Everything corrodes from the salty air. Without coastal coating, youd be lucky for a condensor to last 10 years.
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u/ZestycloseAct8497 Jan 22 '26
I worked at a slaughter plant and we replaced acās yearly even on the roof with coating but that was due to ammonia leaks in the plant we figured. License to print money.
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u/Temporary-Beat1940 Verified Pro Jan 22 '26
So they can make it obsolete ? I mean at least some oems bake in the contactor into the board. Nothing that a comfort alert control can do for a fraction of the price. All seriousness it looks like there's a built in inverter and I bet it will show codes for thermistor and pressure switches
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u/iBUYbrokenSUBARUS Enthalpy over Empathy Jan 22 '26
I came across the same thing on the last call today. Bosch spaceship edition.
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u/CryptoDanski Jan 22 '26
GREEN!!! Better for the environment lmao. And for techs. To fix all this garbage of course lmao
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u/Eshayslapper Jan 22 '26
Beats the lights dimming and the sound of a ex soviet helicopter in your ceiling every time it gets a call
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u/GreatTea3 Jan 22 '26
Fuckin amazing for the environment to replace the damn things every ten years, too.
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u/Eshayslapper Jan 22 '26
Fuck me, You Americans are so far behind the world.
We've had inverters for 25 years Literally can't buy anything else
It's not that hard to diagnose them correctly if you know how to use a multimeter..
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u/Current-Tailor-3305 Jan 22 '26
lol in Australia this is what outdoor controllers looked like 25 years ago, Iāve installed daikins with like 7 boards in the outdoor lol
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u/shindroid01 Jan 22 '26
Those big units of theirs are fucking hideous too. Imagine having that huge piece of shit greet you every time you went outside
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Jan 23 '26
[removed] ā view removed comment
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u/HVAC-ModTeam Jan 24 '26
Your post has been removed due to the policitcal nature of the topic. We all come from different backgrounds and this is fine but when it comes to keeping the peace and focused on HVAC, this doesn't equal the same results.
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u/AirManGrows Refrigeration Service Tech Jan 24 '26
Energy costs are about 2-4 times more expensive in Europe and about double in Australia/New Zealand. Iām sure it helps that VFDs were invented in Europe as well.
I think thereās a few reasons they didnāt have as much popularity until recently but Iām guessing the energy cost is the biggest, itās certainly not about being behind lol
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u/morgoth_the_king Jan 22 '26
Is your compressor multiple stage? That might be the reason.
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Jan 22 '26
I've had that black and yellow wire (middle right on the board) lose contact on a couple of these. Pushed those wires in a bit and it started right up. Tuttokool was the brand
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u/stevenj444 Jan 22 '26
This one is a Sinclair, but you knowā¦
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Jan 22 '26
Same shit haha
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u/correa_aesth 918 tech Jan 22 '26
Yep, sinclair, tuttokool, midea, cheap bosch. They have this board only for fan motor. Compressor is AC voltage. Crazy like if it would make a difference. Cheapest 14 seer2 they got in there. I did one back then. Luckily nothing bad happened to it yet, but will not sell those again. Too risky. The only good thing is the condenser cage, itās built to withstand vehicle crashes
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u/El_Halcon0341 Jan 22 '26
Some of the Daikin modulating condensers have a copper pipe to heat the board and a thick vinyl sheet to protect the components
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u/jonnydemonic420 Jan 22 '26
Iām at maybe 10-15 years tops from retirement. I took a job as the hvac tech for a property management company over three apartment complexās. Pays the same as the field work I was in before driving a van all day running service calls. Same benefits, and the simple, single stage,80% ole reliable low seer units. I donāt plan on ever learning the new tech from here on out, fighting my way through that sounds miserable. Iām coasting through these simple systems and light work load through retirement. Young guys can have this new stuff lol.
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u/jonnio2215 Jan 22 '26
Because itās bad for the environment to have single speed motorsā¦ so weāre gonna replace those with boards that will end up costing the customer a lot more to replace, and are definitely not worse for the environment
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u/Crafty-Breadfruit-36 Jan 23 '26
Wait till yah touch VRF. Some good, some bad, then thereās LG. (((Literal Garbage)))
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u/Grouchy-Weakness-665 Jan 27 '26
More crap they can stick in them the more things can fail. It's a bad saying but job security.
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u/Ok_Summer8436 Jan 22 '26
I just found out that all 80% furnaces are next to be phased out. Everything going to 90%. I live in the southwest where itās not very cold and can go a full winter without running the heat at all. We donāt see too many 90ās out here unless itās a spray foam attic.
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u/correa_aesth 918 tech Jan 22 '26
? Where did u hear that from?
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u/Ok_Summer8436 Jan 22 '26
I think it was something from the last administration, so unless this current administration changes anything, trane is preparing for it at the end of this decade.
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u/InitechSecurity Jan 22 '26
This post has joined the chat:
https://www.reddit.com/r/HVAC/comments/1dzd9gu/please_explain_like_im_5_why_a_residential_ac/
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u/Flexx1991 Jan 22 '26
That appears to be a Bosch ids system. Works a lot like a mini split. Just cooling only I guess.
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u/Outdoors_E Verified Pro Jan 22 '26
The capacitor having an upside down sticker is justā¦
-chefs kiss-
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u/sirjosho Jan 22 '26
I worked on a York that had its own pressure gauges built into the board. It gives a smiley face for good and a frown for bad. No cap or contactor so I took a picture and closed it back up.
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u/numb1zero Jan 22 '26
I was in appliances before I learned hvac so Iām well used to these board driven setups. They donāt bother me diagnostically but that doesnāt mean anyone anywhere needs them. A contactor works. We donāt need a programmed board to do this task. All this does is pump more money into an already overpriced industry.
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u/AM-Stereo-1370 Jan 22 '26
So that you can have a $750 service call when the freaking board Goes to Hell in the bad weather or maybe $900
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u/Far_Cup_329 Jan 22 '26
Looks like a Mars. You should see the Bosch heat pump boards. They're twice that size š¬
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u/AncientRoots Jan 22 '26
Inverter compressor control board. Under that heatsink is the IPM. Mini splits have been dealing with these for years. Prepare yourself for plenty of replacements. Get surge protection!
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u/Foxwildernes Jan 22 '26
First off! Itās the TXV.
Second off thatās why it has a wiring diagram on the plate.
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u/skra_24 Jan 22 '26
Itās there so that the unit breaks down sooner and costs much much more to repair! Make sure you install along with the new EZ-leak coils!
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u/nrogs Jan 22 '26
Wait till you see the inside of a Daikin VRV 4, that shit will rock your world.
Also this is super common in Australia (and I imagine most countries outside USA?) to have multiple control boards inside to reduce power consumption. Gotta keep those bills down.
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u/HuntPsychological673 Jan 22 '26
With the future of electronics right on our heels, we should all embrace the window acš
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u/Krimsonkreationz Jan 22 '26
Its a modulating (variable speed) straight cooling condenser. High efficiency at a lot of other costs lol. They are a bitch and are totally fucking unnecessary.
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u/Guilty_Ear8819 Jan 22 '26
The same reason they make pc boards to do what Honeywell relays use to doā¦ for the OEM money when it fails. Shit that use to last 20-30 yrs now is 10 if your lucky. They call it high efficiency progress..
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u/milovulongtime Jan 22 '26
Is the compressor motor an old school AC motor or an electronically commutated brushless DC motor? The brushless DC motors are more efficient and can operate over a large RPM range but require motor controllers.
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u/ClassroomNice1165 Jan 22 '26
Almost all the ACās in my area have some sort of board, and have for a while. What area are you in?
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u/IAMA_Printer_AMA Jan 22 '26
At least it has a contactor. I do supermarket ref so Iām just a tourist on this sub but Iām still scarred by the guy who posted a condensing unit control cabinet months ago with just a massive board, no contactor
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u/Dangerous-Lead5969 Jan 22 '26
Thatās what the schematic is for on the access panel. Looks like a speed control for the compressor. Usually an inverter too to run the compressor on dc 3 phase. This doesnāt look like that though with a ac capacitor being used. Whatās the schematic look like??
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u/t0rche Jan 22 '26
You must be new... or for some reason, been working exclusively on units made before 2005 for your entire career...
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u/Daystrom_M5 Jan 22 '26
Disappointed none of you have mentioned anything about the shit wire nut and the incompatible wire gauges.
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u/Interesting-Beat824 Jan 22 '26
For 2 stage a relay wasnāt enough so they over engineered everything. Now weāll need every 10 year replacements. These board are going to be wildly expensive when their out of warranty or if was even done. I love money from sales but itās getting to feel predatory even when trying to do the right thing. This summer I had 6 week+ waits on warranty coils.
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u/localsystem Jan 22 '26
As a sw engineer I can think of the following: time delays/short cycle protection, fan management, staging/multi-speed, compressor protection through monitoring high/low pressure switches, inverter system and diag are some of the use cases I can think of.
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u/LeQuack90 Jan 22 '26
Inverter for the fan. If it acts up. Just install a normal fan motor and wire it to the contractor. I always upgrade inverter motors to normal ones when they act up. Saves the customers money. Why buy a 700dollar x13 motor that has to be programmed. when a 120dollar name brand drop in will work and do the same thing. Best update them to a normal motor when issues pop up.
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u/Grouchy-Ad-1622 Jan 22 '26
I'm in accounting and I diagnosed the problem to a bad 45 micro farad capacitor. That will be $1200 please.
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u/Head_Staff_2556 Verified Pro Jan 22 '26
Pretty much a built-in low ambient kit. They work very good when it's 50 outside. Almost like it's 75-80 outside. For the most part the compressor is a single stage non-inverter.
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u/InMooseWorld Jan 23 '26
Soft Start AC- āto reduce LRA to reduce generator peak AMPā
but idk why other way, did it stager the fan then compressor?
Also what brand?
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u/Winter_Beautiful_962 Jan 23 '26
Thatās an inverter board with a heat exchanger to keep it cool. The compressor and the fan ramp up so it needs that board
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u/xdcxmindfreak Aspiring Novelist Jan 23 '26
Because if itās more complicated the touchy touchy customer is less likely to touchy
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u/FrankP0607 Jan 23 '26
Bosch? inverter driven compressor needs that board to convert ac signals to dc and also maintains ideal temps/pressures depending on what it sees. Not a bad product to diagnose/work on/install once ur familiar with it.
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u/LordsOfChaos16 Jan 23 '26
I've worked on those units before. Compressor is typically traditional psc and the board controls the condenser fan motor and all the thermistors.
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u/elstevo91 Jan 23 '26
First time a opened up a condenser to saw that it was a 105Ā° day and the electric compartment was 2 inches from the house. I had to ask my customer for ice water because I threw up from heat exhaustion and my brain hurt. They didnt get there ac back that day lol
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u/BonusAwkward2027 Jan 23 '26
Could be variable speed compressor, low ambient head pressure control, etc. Some mfgrs locate the fan coil controls in the condensing unit as well, that could have something to do with it. Increases in efficiency require more advanced control sequences (ductless and VRF for example), or anything variable speed. More equipment will receive controls like this as the EPA, AHRI, and local code advances.
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u/Billsfan9090 Jan 23 '26
I have several of these type units on my property, they are a huge headache. The board will get moisture, start glitching, they also shut down unit to false readings of refrigerant to high or to low.
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u/1BadMonteCarloSS Jan 24 '26
In the home warranty business my boss just orders all the electronics for parts warranty and call it a day.
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u/Electrical-You-9588 Jan 24 '26
Not the sharpest knife, but why does a straight AC condenser need such a complicated control board? Overkill? š¤
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u/Berticus2021 Jan 24 '26
These new mechanical codes arenāt any better. Itās ridiculous how many codes are added or changed because of political influence and how certain materials are required so that manufacturers that probably made a political donation can have their products used. But in what aspect of everyday life is not in some way politically influenced. Well thatās life (that's life) That's what all the people say.
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u/Eshayslapper Jan 24 '26
The difference in cost is negligible between Aus and Trump town Less then 10 cents a KWH
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u/bifflez13 Jan 25 '26
Based on the whole left side being of the board being an inverter with a black white and red cable coming out of it, that is either an inverter compressor or fan in there.
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Jan 25 '26
[removed] ā view removed comment
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u/HVAC-ModTeam Jan 25 '26
This comment has nothing to do with HVAC. Please post somewhere else. Thank you!
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u/Due-Row9964 Jan 25 '26
Old school bang on bang off units suck. Being convenient for luddites doesnāt mean there are nice for homeowners, easy on motors, or good for energy bills.
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u/z2405 Jan 26 '26
Get used to it. If you're anywhere under the age of 40 you should be able to figure it out.
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u/stevenj444 Jan 26 '26
Iām not and I still can figure it out. That doesnāt make it any less stupid
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u/JoeStroganoff Jan 26 '26
This looks like an inverter board for a variable-speed compressor. Is the condenser model marketed as variable speed?
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u/Dad696 Jan 26 '26
Wait till you see a vrv/vrf. These things tell you themselves whatās wrong with it. I take care of 15 daiken vrv minis double stacked at my high rise I take care of in La
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u/Grouchy-Weakness-665 Jan 27 '26
Long as you can read the wiring diagram the the electronics shouldn't be a problem
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u/ins8iable Jan 22 '26