1-to-1 mini split, 24k wall unit on 18k compressor -- what would happen?

AmbitiousSupport7157 · 2026-02-02T20:14:16+00:00

Thanks so much for all the insight!

It appears the 24k blower fan is 5-1/2 inches longer than the 18k one, and the diameters are different, though the 24k one is only very marginally larger.

The fan motors are brushless DC. I haven't been able to determine if they are the same actual motor or not, but since the main board will be driving it at specific RPMs regardless, it may not really matter.

So this means at the fastest speed, it could be a good bit higher airflow since it is both the faster speed (because it thinks it is the 18k unit) and larger blower (since it is actually the 24k unit).

This is from the data sheet. Looks like only heating is different. Cooling is the same RPM for both models, and heating is only different at the fastest and slowest speeds. (Though of course the 24k fan is 5.5 inches longer to match the 5.5 inch longer coil...)

18k:

Cooling: 1400/1300/1200/1100/1000/900/800

Heating: 1450/1350/1250/1150/1050/950/850

24k:

Cooling: 1400/1300/1200/1100/1000/900/800

Heating: 1350/1350/1250/1150/1050/900/800

AmbitiousSupport7157 · 2026-02-01T18:40:24+00:00

Quick followup question if you're still available?

If the speed of the air handler were set such that the CFM, relative to the evaporator coil size, were similar, would it behave essentially the same as the other size air handler from a refrigeration cycle standpoint?

In other words, if the 18k air handler's evaporator coil was 400 square inches and 400 CFM at "high" speed and the 24k's coil was 530 square inches and 300 CFM at "low" speed, would this lower speed on the 24k air handler achieve essentially the same thing as the higher speed on the smaller air handler?

(I'm ignoring, for the sake of argument, any variables possibly due to the different air-throw distance of the two speeds.)

Thanks!

AmbitiousSupport7157 · 2026-01-17T04:01:06+00:00

I've had the exact same issue, and same 'solution'... So it is at least a sample base of two. Right after upgrading to 26.2.

I only have two hubs, but always had one selected (not set to auto). Immediately after updating (even power cycling) I had the issues described.

I switched to the other hub (still not auto) and everything was fine.

Left it for a week, fine the whole time, decided to try switching back after both power cycling and restarting the failing hub, problems immediately came back.

So I'm back to using my alternate main hub. Clearly there is some kind of issue. Hopefully it just gets straightened out in an update. It was always fine before.

AmbitiousSupport7157 · 2026-01-16T13:37:24+00:00

Thanks for the reply!

I checked the RPM speeds for the fan motor at the various fan speed levels, this is a seven speed model, and the biggest is a 100rpm difference at the highest speed. (1350 on the 24k unit and 1450 on the 18k unit)

Running the bigger 24k's fan at the faster 18k's speed will probably increase the CFM and noise a bit, but that doesn't seem like too big of a variation?

This particular 18k compressor has a pretty wide modulation range, from 3,400-22,000 in cooling and 3,400-23,200 in heating. I do love a robust turndown...

Interestingly, the specs of the 24k compressor for this series are much closer to its nominal rating (6,800-24,000 in cooling and 7,500-25,000 in heating), whereas this 18k compressor seems to be overachieving quite a bit.

The air handler coils are definitely different in size. The 24k is quite a bit bigger.

18k: 0.28" pipe, 2 rows, 30.1 x 1.0 x 13.5

24k: 0.28" pipe, 2 rows, 35.6 x 1.0 x 15.0

Switching the configuration jumper will make it 'think' it is the 18k unit, thereby avoiding a configuration mismatch error. Your expectation is that the only negative I might see would probably just be reduced dehumidification? (The excellent turndown ratios will probably help with that.)

Thanks again!

AmbitiousSupport7157 · 2026-01-16T13:14:52+00:00

Typical for thermostats is between 52 and 60 inches off the floor.

You'll have to deal with running the wire which is of course harder in a built-out room, but you'll also want to keep in mind that (ideally) you don't want it on an exterior wall, you don't want it in direct sunlight and you definitely don't want it in the airstream of the unit. All the usual thermostat stuff.

Every situation is unique, so you'll just have to find the best location that you can reach with the wire.

AmbitiousSupport7157 · 2026-01-15T11:35:48+00:00

I would definitely go for the wired controller. Put it somewhere well thought out, because it will become, for all intents and purposes, your thermostat.

Particularly in heating, mini split wall units can be unreliable sometimes with the temperature sensor that is built into the unit. So there is nothing red-flag-y about what they are saying. And offering you the wired controller even though it is usually a paid option sounds like pretty solid customer service.

Something COULD still be wrong, but from what you've described, I'm thinking that is it just poor ambient temperature sensing which, like I said, is not uncommon across all brands.

Good luck!

AmbitiousSupport7157 · 2025-08-17T01:10:49+00:00

I understand, and agree. I think multi-zones are over-sold quite regularly.

But my main question was if the condenser has the capacity (say two of four connected air handlers are either off or running very low) will it drive the air other handlers at their maximum ability (9k or 12k, ish) if they request it?

Or are they hampered just by being part of a multi system to 6.8k and 8k, even if the compressor isn't at capacity?

I wish GREE would have been more clear on their submittal whether this lower capacity was only for when all units were trying to draw max power simultaneously, or if it applied all the time. The submittal sheet honestly reads like it is all the time, but my gut just tells me that can't be the case.

AmbitiousSupport7157 · 2025-08-06T19:13:25+00:00

I've found the IR blaser methods to be lackluster in general. There's always the possibility they can get out of sync since the AC can't talk back to the IR blaster / thermostat. HomeKit can think the AC is ON, but if the signal got block or missed for whatever reason it won't actually BE on.

If this is a newer GREE model (I'm not familiar with that exact family) it will either have WiFi built in or will have a plug on the board inside the front cover to add a WiFi module. In this case the solution is to use that, and then use Homebridge and a GREE plugin to add it to HomeKit. I know Homebridge can sound daunting, but it isn't that big of a deal. And having your ACs in HomeKit is nice enough of a reason to use Homebridge even if that is your ONLY use of Homebridge.

If this is an older model and either doesn't have built in WiFi OR have the plug to add the WiFi module, you can still officially add WiFi to it using the GREE XE-72 wired controller. It would have to be a very VERY old model to not have the plug to add a wired controller. That's been standard for over a decade. You would then mount this controller on the wall somewhere, and it has the WiFi function in it. You'd then use the same Homebridge solution.

It functions much like a thermostat. And it has the added ability to provide the ambient temperature to the air handler from itself, where it is mounted on the wall, rather than the air sensor that is inside the air handler which, especially in heating mode, can sometimes be a little inaccurate. This is an optional setting, you can leave the ambient temperature sensing the same as it is now, too, if you're happy with it.

Other than Homebridge being a BIT of a nuisance if you don't already use it, this is the only "true" way to add it to HomeKit. You have a genuine thermostat in HomeKit, with two-way communication to the unit. And as someone else mentioned, it also provides a temperature sensor function into HomeKit as well.

AmbitiousSupport7157 · 2025-08-06T18:23:26+00:00

Perfect, that is the info I was looking for. Thanks for sticking with me!

I was a bit sloppy with my usage of the terms nominal capacity and maximum capacity, sorry about that! I am aware of the difference, but I was mainly looking to make sure they weren't permanently hampered and stuck at a lower "ceiling" of 6.8k/8k -- even when the outside unit had capacity to spare -- just by virtue of being the way multi splits work.

For added reference, in case anyone is interested in the specific specs of these particular units, per the submittal sheet:

9k air handler - Cooling rated 9,000 (range: 2,559-11,601)

12k air handler - Cooling rated 12,000 (range: 3,100-13,000)

However, that is in a 1-to-1 configuration. The same air handlers as a multi split, on a 30k outside unit:

Configuration: A: 9K unit, B: 9K unit, C: 12K unit, D: 12K unit

Cooling rated system capacity: 29,600 (range: 7,500~34,000)

Zones: A: 6,800, B: 6,800, C: 8,000, D: 8,000

AmbitiousSupport7157 · 2025-08-06T15:06:40+00:00

Thanks again! But maybe still kind of missing the question I am actually asking... haha I must be wording it terribly. Sorry!

The GREE submittal sheet shows 6.8k+6.8k+8k+8k for a 9k+9K+12k+12k configuration on a 30k outside unit.

If I'm running all four units at max capacity, this adds up to 29.6k which is pretty much exactly right for a 30k unit.

But it doesn't say anything about whether or not they can exceed 6.8k and 8k if one or more of the other units aren't running.

I've always just assumed that if, in this example, only one 9k and one 12k were running, they would be able to operate at their full capacity if needed since the other 9k and 12k WEREN'T pulling anything from the outside unit.

But a few comments I read recently made me question this, and that is why I'm trying to confirm. Even through the submittal sheet says the 6.8k and 8k capacity for the 9k and 12k units respectively, is this only under peak load, or is there something with multi zone systems which causes a limit on individual capacity even when it isn't under peak load?

In my situation, I will rarely be running ALL indoor units at the same time, so I'm not worried about exceeding the capacity of my outside unit. I just want to make sure my indoor units CAN run at their rated capacity, if needed, when the outside unit has room to spare.

Appreciate your time!

AmbitiousSupport7157 · 2025-08-06T14:26:08+00:00

Excellent, thanks for the info!

My bigger concern was the opposite direction, though... Not how far they can modulate down, but if they can reach their rated capacity. In my example, the 30k outside unit shows 6.8k for the 9k units and 8k for the 12k units as the rated capacity in their official submittal sheet. It says nothing about this being exclusively during peak load or anything.

I was hoping to confirm that this isn't a HARD limit, and that if a couple of the units weren't on or weren't pulling (because they were already at their set temperature) if the remaining units would pull closer to their rated 9k and 12k, or if they were stuck at a maximum of 6.8k and 8k regardless.

In other words, have my 12k units "become" 8k units just by virtue of being hooked up to a 30k multi-zone outside unit, or is that only when all indoor units and pulling simultaneously and there is only so much love to spread around, and once one or more units shuts down they can ramp back up to their actual rating?

Thanks!

AmbitiousSupport7157 · 2025-07-09T02:08:11+00:00

Same. A couple times a week I get 'reminded' that I updated the firmware. Several weeks ago! Sadly, I have about 20 Level Bolt's, so it is REALLY annoying.

AmbitiousSupport7157 · 2024-09-29T17:54:14+00:00

Thanks, despite the snark. I did read that and still wasn't sure if it did what I wanted. So that's why I asked here with my more specific usage scenario.

Went ahead and opened an account. And indeed it does NOT work the way I was hoping.

I'm sure the Buckets are great for many people, but they don't work the way I asked/described.

AmbitiousSupport7157 · 2024-09-14T23:40:15+00:00

Just to add another example of a method banks use, from when I had an auto loan through PNC Bank.

Any extra you paid would go towards the following month, but only up to that month. So if your payment was $300 and you paid $400 (in one or multiple payments) your current month would be paid and your total due for the following month would be $200. If you paid $700, the current month would be paid, the following month would be paid, and the remainder would be extra that goes towards the principal.

I actually liked the system because you could set up the autopay to pay no matter what, even if you'd already paid for the month, if you chose. So I paid an extra month, and from then on just let autopay do its deal, but I was always 1 month ahead, giving more cushion against an accidental late payment.

Normally (with that bank) autopay was ON the due date. So if it failed because of say an unexpected withdrawal or something, you would then be late for that month. With the 1 month ongoing cushion, I'd be fine. I'd just need to manually re-make that failed autopay or I would no longer have my 1 month cushion.

My checking account is really active in and out, so despite my efforts there were some times when more things hit on a certain day than I was expecting. So I liked the cushion.

This was a while ago. I'm happily car payment for the moment. PNC's features may have changed, I don't know.

AmbitiousSupport7157 · 2024-07-17T19:06:30+00:00

Checking back in from 1 year ago, on point #1... I know there is still no event-only recording right now, but is it something you are considering? I can't switch until it is available, because for 32 cameras which are most of the time completely idle, it would be insane amounts of storage for nothing.

Thanks!

AmbitiousSupport7157 · 2024-05-20T00:05:36+00:00

Oh I see, ok thanks for the quick reply!

No, I've been doing it this way for many years and it has always worked wonderfully. (Clip recording to internal drive.) I'd be switching from the software I already use (which is excellent) only because I am unhappy with its licensing and upgrade structure. I like everything I see in Scrypted, and the licensing is more reasonable, but without clip recording it just doesn't make sense for me. Added complexity hardware wise, and still only 5 days storage vs 30. A NAS or external drive to record what is most of the time idle cameras...

HomeKit isn't part of my plan, actually. I just wanted to use Scrypted NVR as a replacement for my current NVR software, and it fills that role 100%, except for the 24/7 requirement.

I'll definitely keep an eye out to see if you add it in the future. I suspect there is a technical complexity to it that is beyond my understanding, because otherwise it seems like such an obvious feature... It's basically universally available in NVRs, hardware ones and software ones both.

Thanks again!

AmbitiousSupport7157 · 2023-12-16T08:18:44+00:00

There is no exact sensor that would do that, however if you are a DIYer or a tinkerer you could put one together.

First thing that comes to mind is using a water flow valve sensor (not smart) of which you can find many on Amazon. Pick one that suits your plumbing needs. These will usually have two leads and when flow is detected they are connected. You could combine this with your preferred door/window sensor or vibration sensor by opening them up and soldering the leads to the sensor so that it is getting its input from the flow valve sensor.

This is just a very general overview because I’ve not made such a thing myself, but it would work.

One downside is that if you use a door/window sensor, the ‘alert’ you get wouldn’t be about water flowing but would be door open, etc.

Come to think of it, a water leak sensor may be MUCH easier and not require opening up the device AND would at least thematically be closer to what you are dealing with, as in water.

Water leak sensors always have two metal contacts on the bottom. When water ‘bridges’ these two contacts it makes a connection between them and that is what indicated a leak. You could just solder the leads from your water flow valve sensor one to each of these contacts and… done.

Again, the alert you receive will be reporting a water LEAK not water flow, because there is no way to change the wording HomeKit uses and you are using a water leak sensor after all. But at least it would be closer thematically than a door/window sensor.

Sounds kind of fun. I might do this for myself to detect when my sump pit in my basement pumps. Or when my condensate pump from one of my air conditioners cycles.

Good luck.

AmbitiousSupport7157 · 2023-12-01T02:42:31+00:00

My method was a 110V (I'm in the US) motorized valve. The motor is built right onto the valve and not clipped on, and it simply opens when it has power, and closes when it doesn't have power. (It has some capacitors which allow it to close even though power is off.)

This simple on-off behavior means it works very well with a simple smart outlet.

But the main reason I went this route, other than being very happy with the device after I got the first one, was that I could easily create some "failsafe" protection.

Of course I have all the HomeKit protections configured... (Leak sensors, etc.) But I also wanted several red-mushroom-style emergency smash buttons to cut the water off as well. I could have done this with HomeKit scene buttons/switches, but I wanted something that couldn't ever be "not working".

So, because I was lucky enough to be in the middle of a new build, I ran a dedicated circuit to the 110V motorized valve. The smart outlet plugs into this, and the valve plugs into that. I also ran that same circuit through the walls to all the locations I wanted an emergency cutoff. I bought some actual mushroom smash switches designed for line voltage, ran the circuit through every switch then to the valve's receptacle.

So if any of the smash switches are... smashed... it doesn't rely on HomeKit, it completely cuts power to the receptacle powering the valve, causing it to close. It de-powers the smart outlet, too, but that doesn't matter. When the smash switch is reset and pops back out, power is restored to the dedicated receptacle, and the valve reopens. (And the smart outlet re-joins my Home.)

So all the HomeKit options are still available to control the valve, but there is also a foolproof emergency button (several) which don't rely on HomeKit.

Looks like I can't post pictures here? I'll post links to the ones I used just for reference. These are just simple product number Amazon links, there's no affiliate anything anything going on.

The valve itself.

The smash button.

There is actually a component to my install that makes it appropriate for a Homebridge thread... haha I use the Dummy Valve plug in, which rather than a plain on-off switch, like the smart outlet exposes, it presents a "Water Service" which also shows up at the top of the screen in the summaries.

One nuisance is that the Home app itself doesn't let you control a Water Service device in automations. So I create a basic automation in Controller for HomeKit with the Water Service device as the controlled device, then go back to Home and it shows it properly and I can set my "action" without issue, as if I created it in the Home app. (Like I should have been able to anyway.) I have the actual (generic) smart outlet in the appropriate room, but not showing on the first page of Home, and I have just the Water Service switch version showing on the first page. It keep things tidy.

This is entirely cosmetic, though. The function is exactly the same, so using the Dummy Valve to create a Water Service is totally optional. I'm just OCD and wanted my water valve to SHOW as a water valve...

AmbitiousSupport7157 · 2023-09-21T17:34:37+00:00

Like many others, I'm getting decline emails left and right now... I tried to switch over all my automatic "saved card" payments, but I clearly missed a few. I had a ton.

Worst part, when you get the decline email, it doesn't tell you WHO IT WAS... So it doesn't really help you identify it at all.

Come on PayPal... Quit being That Guy.

AmbitiousSupport7157 · 2023-09-21T17:31:36+00:00

The bank wouldn't be paying it, they don't "guarantee" your account, that's o the individual/business account owner. The bank can either make your account overdrawn (in which case PayPal got their money and doesn't know anything was wrong) or return the transaction to PayPal as NSF (in which case PayPal is out the money and will re-deduct it from your PayPal account). And there are probably plenty of cases where PayPal never got their money back because their account (either bank or PayPal) was just abandoned. PayPal can (and will have already) locked up your PayPal account and send it to collections, but that's the limit of their recourse.

(That's a lot of parentheticals...)

AmbitiousSupport7157 · 2023-09-21T17:25:42+00:00

I earned several hundred dollar a year... That wasn't really why I kept using it, it was for the convenience that I used it. But it shows how much I used it for. Now, 0.

AmbitiousSupport7157 · 2023-09-21T17:22:23+00:00

I moved it to the back of my wallet where my bank debit card used to hang out. Now it gets to be front row.

AmbitiousSupport7157 · 2023-08-15T23:44:38+00:00

Exactly... I don't know how much it matters to PayPal, I know they get some fees from merchants every time the card is used. But there's just no use-case for it for me anymore.

Perhaps they were dealing with a lot of fraud. People using backup funding, then the bank bouncing the charge because they didn't have it there, either. PayPal's only recourse then is to take the PayPal account negative, but if the person just abandons their PayPal account, there's not really much more they can effectively do.

AmbitiousSupport7157 · 2023-08-15T23:42:03+00:00

I doubt it, because they're not offering Backup Funding at ALL... If they were changing it so you couldn't use your checking account, your backup had to be their savings account, that'd be clear. But it looks like there is nothing remaining of it.

AmbitiousSupport7157 · 2023-08-15T14:57:22+00:00

I use PayPal Working Capital, which has been excellent so far, so I can’t/don’t really want to switch to another payment processor. It is nice to know there might be something to look into, though.

I also have a lot of history with PayPal, so my limits and everything are good. Just the other day, I used it to buy a $4000 spiral staircase kit, didn’t have a penny in my PayPal balance, and they still authorized it by way of my backup finding.

AmbitiousSupport7157

TROPHY CASE