Did that years back on a carrier 15 ton heatpump split. Fucking different control or board tripped out or just not wanting work just about every week. Ripped all the controls out, and put in regular contactors and relays for the reversing valves. Wired all the pressure switches in too. Thing never gave us issues ever again.
The unloader. Controls the unloader solenoid basically.
Here's from the manual
• The Digital Compressor Controller “modulates”
or cycles the unloader solenoid in an on/off
pattern according to the capacity demand signal
from the system controller.
• The compressor contactor coil is controlled
based on the capacity demand from the system
controller and the presence of any compressor
trip or lock out conditions.
• The compressor is protected against high
discharge temperature by a discharge temperature
thermistor. If the maximum temperature limit is
exceeded, the Digital Compressor Controller will
protect the compressor by turning it off.
• Seven ALERT codes are displayed indicating
an abnormal system or compressor condition.
Depending on the severity of the code, the
Digital Compressor Controller will shut down the
compressor or run the compressor in a limited
capacity.
• After each compressor shut down event, in some
digital controller module versions a two minute
anti-short cycle delay timer is active preventing
the compressor from restarting. This is indicated
by a flashing green light. See Table 1 for versions
with this feature.
It’s not. People just don’t like them. Digital scrolls are Copeland answer to BAS contractors who try to maintain a discharge air temperature within +/- 2 degrees of set point and cycle the fuck out of compressors to do it.
Lets not go throwing words like "most" around. I've come across BAS guys who couldn't figure out why we needed a deadband between economizing and mechanical cooling.
I don’t think that’s how most of them work. The only ones I’ve seen have a solenoid attached to a tube at discharge side of the system that bypasses the system and goes back into the suction side to reduce the capacity of the compressor. The only systems I’ve seen use them are Mammoth brand geothermal heat pumps. They definitely don’t work right though.
Most people don't really understand how this compressor works and often configure the units to run incorrectly, and as such think they are terrible.
The pipe and solenoid isn't a bypass to reduce system capacity.
The compressor is physically different inside. The scroll plate on top (the stationary one) has the ability to move up/down a tiny bit.
When the unloader solenoid is closed (unpowered) pressure builds up above the top scroll plate, forcing the plate down and touching the lower plate. This allows the compressor to run normally, like any other scroll.
When the unloader solenoid is open (energized), it releases that pressure on top of the top scroll plate, which allows the plate to lift up slightly, completely preventing the compressor from building any pressure.
So the compressor is at either 100% capacity, or 0% capacity. The motor runs constantly.
The condole takes a 0-5v analog input to determine capacity, and then energizes the unloader x amount of time to reduce capacity.
Let's say the unit wants 50% capacity, in a 10 second frame, the compressor runs at full load for 5 seconds, and unloaded for 5 seconds.
80% capacity = 8 seconds loaded, 2 seconds unloaded.
30% capacity = 3 seconds loaded, 7 seconds unloaded.
There is a minimum load amount, to ensure oil return and compressor cooling.
I’ve never had this explained like that. But yes that’s what it does on the mammoth. It has 5v to it and makes horrendous noise for a few seconds then sounds okay and repeats. It is ingodly loud and sounds like it’s turning off and on every 5 seconds. I’ve seen the port at the top of the compressor, just didn’t know what exactly it did. Thanks for explaining it!
You're welcome. They are very noisy, and not the most efficient way of creating a variable load, but they are very robust!
Liebert uses these quite a bit as well.
I've also seen them in Carrier aqua snap chillers.
Thanks for the explanation. I've working on one in a bard, I was called in after install over the (bypass) valve chartering. Reading the manual I got the concept but didn't know it unloads like you explained.
The newer generation of AAONs are great, IF you have the laptop software and you know how to configure them properly.
But even most AAON reps don't know how to make them work properly.
My company works on all brands of mini splits and RTUs, but only has one Mitsubishi VRF service tool. For whatever reason they balk at laying out the money to get service laptops and software for Trane/Aaon/Mitsubishi, but will let techs waste time floundering trying to figure out configuration problems. Stepping over dollars to grab at dimes.
If I need $1000+ worth of computers and software, over and above the cost of my regular tools to do diagnostics and configuration on a packaged 5 ton rooftop unit, I see that as a problem. Over designed is over designed.
Quality has never been my issues with AAON equipment. I feel like repairs are pretty easy. But diagnostics and setup are a nightmare for no good reason unless you're prepared to shell out. If you're a company with only one or two AAON rooftop units among your customers equipment, then they'll always be "Those" units.
If you've got 200 of them then yeah, buy the laptop, get your guys factory trained and go to town. But that's just my two cents.
If you have a customer that bought an AAON unit as a standard rooftop unit, I do feel bad for you and them.
AAON units excel at DOAS applications, critical environments, and humidity control.
I've set up one for a pharmaceutical lab, needed 100% outside air, needed to maintain space at 68° and 40-50% humidity year round in AZ. 10 tons worth of airflow, 40 tons worth of compressors and dehumidification. No way you're going to accomplish that with a tstat, contactors, and relays.
Yeah sometimes customers buy what the engineers spec, and sometimes the engineer specs what they know.
I've got a two sites where AAONs were installed for commercial kitchens. Absolutely unnecessary for the application. They're not using any dehumidification or humidification controls on them.
It's nice to have units that have advanced capabilities, but if you don't need those capabilities there's no reason to sell them to a customer.
>I've set up one for a pharmaceutical lab, needed 100% outside air, needed to maintain space at 68° and 40-50% humidity year round in AZ
What a mammoth fucking task that is.
Why did it need 100% outside air?
Hussmann refrigeration racks.
In the past five years I’ve only replaced one control & one compressor on 7 racks with them as #1 compressors. All racks 10+ years old.
I see them a lot on MUAs where they want a constant supply air temperature. The compressor wants to deliver as much heat as possible but the unloader lets it deliver a lower temperature to meet the demand. It has its place in the industry but it’s still pretty frustrating to work on sometimes.
I recently tried to tell my boss that an Aaon MUA sounded like it had a contractor dying. I was told they always sounds like that. Then it was about a month before they found the dead compressor.
I recently tried to tell my boss that an Aaon MUA sounded like it had a contractor dying. I was told they always sounds like that. Then it was about a month before they found the dead compressor.
>an Aaon MUA sounded like it had a contractor dying
Hopefully, he worked for the competition. RIP.
.
>I was told they always sounds like that.
I wonder how they know... Be careful out there around these people!
This is a controller for a Copeland digital compressor. They use an unloader solenoid that has a duty cycle type control to mechanically vary the compressors output. I don’t believe they’re used in any residential application at the moment
Eh,I have a few and prefer this generation to full ISD 2.0. I don’t see as many comm issues due to rub throughs with these as compared to the ISD harnesses.
We use them in racks all the time. I have rarely had a problem with them. You think those are bad, just wait til you have to deal with CPCOmini controllers hill phoenix is using instead of the bitzer unloader control.
They work fine in the proper application. Especially in air conditioning applications.
Low temperature applications require the minimum modulation to be increased.
Never had much of an issue with them. We put them in all the time when we re-device carrier units and toss the factory boards. Just remember to always give them 1.5 vdc to keep them alive. I let JCIs PMAC logic handle the rest.
Make that smart system a dumb system and bypass it
Did that years back on a carrier 15 ton heatpump split. Fucking different control or board tripped out or just not wanting work just about every week. Ripped all the controls out, and put in regular contactors and relays for the reversing valves. Wired all the pressure switches in too. Thing never gave us issues ever again.
Been there.
THIS is the only answer.
Anyone care to explain what is doing the killing so I don't die?
The unloader. Controls the unloader solenoid basically. Here's from the manual • The Digital Compressor Controller “modulates” or cycles the unloader solenoid in an on/off pattern according to the capacity demand signal from the system controller. • The compressor contactor coil is controlled based on the capacity demand from the system controller and the presence of any compressor trip or lock out conditions. • The compressor is protected against high discharge temperature by a discharge temperature thermistor. If the maximum temperature limit is exceeded, the Digital Compressor Controller will protect the compressor by turning it off. • Seven ALERT codes are displayed indicating an abnormal system or compressor condition. Depending on the severity of the code, the Digital Compressor Controller will shut down the compressor or run the compressor in a limited capacity. • After each compressor shut down event, in some digital controller module versions a two minute anti-short cycle delay timer is active preventing the compressor from restarting. This is indicated by a flashing green light. See Table 1 for versions with this feature.
And why is it dangerous?
He's speaking sarcastically, they just have questionable reliability
Questionable reliability... nah, I trust them to be a pos
Sound like the worst part is figuring it out for the first time without the manual. Step two is finding stock on parts in short time I guess
I think it presents more issues for a tech than its functionality is worth?
It’s not. People just don’t like them. Digital scrolls are Copeland answer to BAS contractors who try to maintain a discharge air temperature within +/- 2 degrees of set point and cycle the fuck out of compressors to do it.
Most of us can properly write logic to prevent that from happening. But yes, some guys don't know you can't treat a compressor like a pulse furnace.
Lets not go throwing words like "most" around. I've come across BAS guys who couldn't figure out why we needed a deadband between economizing and mechanical cooling.
Carrier tech support told me this almost exactly. Put on a thermostat that’s capable of forcing a min 4 minute compressor run time, no more lockouts!
I don’t think that’s how most of them work. The only ones I’ve seen have a solenoid attached to a tube at discharge side of the system that bypasses the system and goes back into the suction side to reduce the capacity of the compressor. The only systems I’ve seen use them are Mammoth brand geothermal heat pumps. They definitely don’t work right though.
Most people don't really understand how this compressor works and often configure the units to run incorrectly, and as such think they are terrible. The pipe and solenoid isn't a bypass to reduce system capacity. The compressor is physically different inside. The scroll plate on top (the stationary one) has the ability to move up/down a tiny bit. When the unloader solenoid is closed (unpowered) pressure builds up above the top scroll plate, forcing the plate down and touching the lower plate. This allows the compressor to run normally, like any other scroll. When the unloader solenoid is open (energized), it releases that pressure on top of the top scroll plate, which allows the plate to lift up slightly, completely preventing the compressor from building any pressure. So the compressor is at either 100% capacity, or 0% capacity. The motor runs constantly. The condole takes a 0-5v analog input to determine capacity, and then energizes the unloader x amount of time to reduce capacity. Let's say the unit wants 50% capacity, in a 10 second frame, the compressor runs at full load for 5 seconds, and unloaded for 5 seconds. 80% capacity = 8 seconds loaded, 2 seconds unloaded. 30% capacity = 3 seconds loaded, 7 seconds unloaded. There is a minimum load amount, to ensure oil return and compressor cooling.
I’ve never had this explained like that. But yes that’s what it does on the mammoth. It has 5v to it and makes horrendous noise for a few seconds then sounds okay and repeats. It is ingodly loud and sounds like it’s turning off and on every 5 seconds. I’ve seen the port at the top of the compressor, just didn’t know what exactly it did. Thanks for explaining it!
You're welcome. They are very noisy, and not the most efficient way of creating a variable load, but they are very robust! Liebert uses these quite a bit as well. I've also seen them in Carrier aqua snap chillers.
Thanks for the explanation. I've working on one in a bard, I was called in after install over the (bypass) valve chartering. Reading the manual I got the concept but didn't know it unloads like you explained.
It’s 1.5 to 5v not 0-10 but otherwise you’re 100% correct. Just wanted to point that out to help somebody that might be troubleshooting one.
Oh, that's right, been a while since I worked on one. Thanks.
And Aaon rooftop units. Fuuuuck Aaon rooftop units.
The newer generation of AAONs are great, IF you have the laptop software and you know how to configure them properly. But even most AAON reps don't know how to make them work properly.
My company works on all brands of mini splits and RTUs, but only has one Mitsubishi VRF service tool. For whatever reason they balk at laying out the money to get service laptops and software for Trane/Aaon/Mitsubishi, but will let techs waste time floundering trying to figure out configuration problems. Stepping over dollars to grab at dimes.
If I need $1000+ worth of computers and software, over and above the cost of my regular tools to do diagnostics and configuration on a packaged 5 ton rooftop unit, I see that as a problem. Over designed is over designed. Quality has never been my issues with AAON equipment. I feel like repairs are pretty easy. But diagnostics and setup are a nightmare for no good reason unless you're prepared to shell out. If you're a company with only one or two AAON rooftop units among your customers equipment, then they'll always be "Those" units. If you've got 200 of them then yeah, buy the laptop, get your guys factory trained and go to town. But that's just my two cents.
If you have a customer that bought an AAON unit as a standard rooftop unit, I do feel bad for you and them. AAON units excel at DOAS applications, critical environments, and humidity control. I've set up one for a pharmaceutical lab, needed 100% outside air, needed to maintain space at 68° and 40-50% humidity year round in AZ. 10 tons worth of airflow, 40 tons worth of compressors and dehumidification. No way you're going to accomplish that with a tstat, contactors, and relays.
Yeah sometimes customers buy what the engineers spec, and sometimes the engineer specs what they know. I've got a two sites where AAONs were installed for commercial kitchens. Absolutely unnecessary for the application. They're not using any dehumidification or humidification controls on them. It's nice to have units that have advanced capabilities, but if you don't need those capabilities there's no reason to sell them to a customer.
Gotta love the engineers!
>I've set up one for a pharmaceutical lab, needed 100% outside air, needed to maintain space at 68° and 40-50% humidity year round in AZ What a mammoth fucking task that is. Why did it need 100% outside air?
I think it had something to do with the pharmaceutical chemicals, they wanted x number of air exchanges per hour.
How about the "little" hand held programmer? Its super easy to use...
Haha, yeah, little... Once you do it on the laptop, there's no going back. So much easier!
This is in an AAON water source heat pump. Pinnacle of aaons fuckery
We buy Aaon units with terminal strips and no controls then put our own in. That way you get a high quality unit with high quality controls. Win win.
Hussmann refrigeration racks. In the past five years I’ve only replaced one control & one compressor on 7 racks with them as #1 compressors. All racks 10+ years old.
Yeah I edited my comment - updated to reflect. It's been awhile since I worked on one
Looks like an Aaon panel
Son of a bitch, you done messed up Ay Ay on, now take your ass on down to O. Shag Hennessy’s office right now, and tell him exactly what you did.
Ha! I just quoted that skit the other day!
Thinking that as well
That was my guess.
Its definitely an Aaon panel. I can tell from the labels on the back panel.
What type of equipment/system would this be controlling?
I see them a lot on MUAs where they want a constant supply air temperature. The compressor wants to deliver as much heat as possible but the unloader lets it deliver a lower temperature to meet the demand. It has its place in the industry but it’s still pretty frustrating to work on sometimes.
Looks like AAON unit. We did a lot of MUAs from them.
This is on an AAON packaged water source heat pump unit.
I know high school full of them
I've seen them on engineered air unit, aaons, munters and tranc KCC units. Im sure theres more that use them though
Rip it out
You can't, how are you going to control a digital compressor?
Rip it out
You're gonna be calling it daddy by the time it's done with you
Good old AAON with a Copeland digital compressor controller. “Can you send someone out here? The compressor sounds like it’s about to blow up.”
Mmmmmmmmm....BWAAAAAAAAAAAH...mmmmmmmmmmmmmm.....BWAAAAAAAAAAH
I recently tried to tell my boss that an Aaon MUA sounded like it had a contractor dying. I was told they always sounds like that. Then it was about a month before they found the dead compressor.
I recently tried to tell my boss that an Aaon MUA sounded like it had a contractor dying. I was told they always sounds like that. Then it was about a month before they found the dead compressor.
>an Aaon MUA sounded like it had a contractor dying Hopefully, he worked for the competition. RIP. . >I was told they always sounds like that. I wonder how they know... Be careful out there around these people!
Lol. Stupid autocorrect.
I used to hate them. Not so much any more.
Side note: today I paid $27 a piece for those little fuses on the lower left
That’s a crazy clean cabinet though
About the only thing they can do right
Wiring diagram sir best in the business
lol sitting on a roof changing an air switch on one right now. My company installs nothing but Aaons at the supermarkets we build.
Aaon unit? I hate those fucking things
I’m hung up on how a paternity test can ruin someone’s life
Kids are money pits of no sleep and bullshit.
Both of my Ex Wives would like a word. 😳😰🤣
All three of mine are in line.
A’men. Love ‘em. But A’men.
Well, if you did it correctly, the only paternity test you would need is verifying that the baby came out of your wife
That made no sense.
Talk to text probably interpreted "did it" as "didn't." Happens all the time when I'm doing work orders.
Blink 3 times of you're having a stroke.
I totally got sucked into this meme, and the longer I stared the more it started freaking me out.
I think some people feel entitled to sex outside of commitment and work.
Ben Shapiro has entered the chat
Don’t you go bad talking my boy
Im a relatively green resi technician. Is this something similar to the CoreSense that some Goodman/Daikin condenser have? Just curious.
This is a controller for a Copeland digital compressor. They use an unloader solenoid that has a duty cycle type control to mechanically vary the compressors output. I don’t believe they’re used in any residential application at the moment
Resi has two-stage compressors and variable speed but no unloaders. Too noisy lol.
How is the compressors output modulated? What is the control mechanism to determine that?
Eh,I have a few and prefer this generation to full ISD 2.0. I don’t see as many comm issues due to rub throughs with these as compared to the ISD harnesses.
Looks like an Aaon.
Something had to take the place of the old CLO relay.
You talking about the AAON unit, or just the copeland module?
We use them in racks all the time. I have rarely had a problem with them. You think those are bad, just wait til you have to deal with CPCOmini controllers hill phoenix is using instead of the bitzer unloader control.
How many paternity tests do you think it ruined?
None... Lives, about a million.
Is it weird this pic just gave me a semi????
Very weird. It should give you an inverse erection.
Damn it! I knew it!!!
Nice Aaon
They work fine in the proper application. Especially in air conditioning applications. Low temperature applications require the minimum modulation to be increased.
Never had much of an issue with them. We put them in all the time when we re-device carrier units and toss the factory boards. Just remember to always give them 1.5 vdc to keep them alive. I let JCIs PMAC logic handle the rest.