Mini-split A/C and Hardwired TStat

[jono]

We have Fujitsu split units (VRF) that have both a wall controller and IR handheld remotes.

I have tried a couple of options over the years. Remotec ZXT Zwave controllers work but are limited and unreliable. And IR is one way only in that any changes made using the AC wall controller is not detected by the ZXT and in turn not reported to HS.

In the end I forked out for the Intesis units and haven't looked back. Wifi but not cloud based, so all 'in house' control. Responsive and you get full control including all modes, fan speeds and direction control is your unit has that. And this method is turely bi-directional, so HS is aware of any changes made to the AC unit no matter what is used (remote, wall controller etc).

With Michael's mcsMQTT plugin, the 'WMP' protocol that Intesis uses is fully supported. Check the Intesis website to see a list a brands and models of AC are supported.

Just my 2 cents worth.

Which Intesis model did you end up getting? I'm also interested in wall control (maybe ecobee), remote control, and HS4 control

[mminehan]

I've been looking for someone that has messed with these. I have the Fujitsu with 2 zones controlling my 3rd floor bedrooms... and the tstat batteries are dead in each unit. total pain when the power flickers. apparently the only way is to replace the entire unit.

The ZXT-600s are rubbish. Although they say they can control more units that the ZXT-120 they actually contol less parameters for each unit (less operating modes, missing setpoints, missing fan speeds). Search these forums and you'll find posts about them. https://forums.homeseer.com/forum/ge...emote-zxt-600 There are other similar posts by others.

I had bought one to replace an older ZXT-120 but gave up on the ZXT-600. In the end I went with the Intesis interface ($$$) and mcsMQTT, which has the advantage of bidirectional communication (i.e. HS can see the state of the AC unit when it is changed by the wall controller for example) and does not need batteries. The ZXTs are unidirectional, as is the case when using IR to control anything.

[outbackrob]

Unfortunately had a negative experience with this device (Remotec ZXT-600US), there is no help on the Remotec website, and none of the contact pages work. Tried to get this device to work on Vera Plus, nothing worked. The device seems to work, but none of the 23 IR codes work with my device, and programming with the remote does not seem to work. I was probably just in a hurry and did something wrong. Not home right now, will be back in a month will try to reconnect.

It's been a while now since I set mine up, but I do remember it was not straight forward. However, once it was completed, I have never had to do anything but change the batteries once because I had it on my calendar to do so.

Here is website that I don't remember being available before: https://remotec.com.hk/remotec_product/zxt-600/

Best wishes!

[gerald_koonce]

Something to consider is the Remotec ZXT-600US. I have a very (VERY) old split system that I am shocked even had a remote, but it has no other app or other interface capability. I didn't think I was going to be able to remotely control it let alone get it to function via HS. Without much more than adding it as a z-wave device, I can control MOST of the functions of my old Mitsubishi. I can turn it on or off, change the temp, change the mode, and change the fan speed. And, it just works. I have had it for a few years now and it is still on the same two batteries. It was the last major system in our house I had to automate and the Remotec made it happen.....

PS: You can still buy them on Amazon: Amazon.com: Remotec ZXT-600 Z-Wave Plus - IR Extender for AC Conditioner : Home & Kitchen

Unfortunately had a negative experience with this device (Remotec ZXT-600US), there is no help on this web site, and none of the contact pages work. Tried to get this device to work on Vera Plus, nothing worked. The device seems to work, but none of the 23 IR codes work with my device, and programming with the remote does not seem to work. I was probably just in a hurry and did something wrong. Not home right now, will be back in a month will try to reconnect.

With the UTY-TTRX you can daisy chain up to 16 units together. We have two units in the kitchen and family room tied to one thermostat.

[Tomgru]

Correct! It’s not cheap. As a general contractor I used my account with a local wholesaler. The UTY-TTRX still cost about $140 each. I also bought my thermostats in bulk on eBay. I got RCS Zwave stats that look as simple as possible because it’s a rental and we didn’t want guests asking how to use it.

I should also mention Fujitsu instructions for configuration are not the clearest, but once set up they’re great.

Thanks! So why 6 of the units for 7 minisplits?

Correct! It’s not cheap. As a general contractor I used my account with a local wholesaler. The UTY-TTRX still cost about $140 each. I also bought my thermostats in bulk on eBay. I got RCS Zwave stats that look as simple as possible because it’s a rental and we didn’t want guests asking how to use it.

I should also mention Fujitsu instructions for configuration are not the clearest, but once set up they’re great.

[Tomgru]

Just for the record, Fujitsu mini splits also offer a 3rd party thermostat option. The UTY-TTRX works similarly to the PAC-US444CN described above. I have 7 mini splits controlled by 6 Fujitsu UTY-TTRX. The fan control is solely by the head unit, and the mini split essentially has two stages of heat and two stages of cool per the thermostat.

My systems are in an Airbnb 2 hours away so the loss of some efficiency is outweighed by the ability to control it remotely.

I've been looking for someone that has messed with these. I have the Fujitsu with 2 zones controlling my 3rd floor bedrooms... and the tstat batteries are dead in each unit. total pain when the power flickers. apparently the only way is to replace the entire unit.

I Looked into these .... So i'd use 1 for each zone, right? then I'd replace the tstats with a Next or Ecobee (i actually already use Ecobee for my other Hvac system).

So i'd need two of these at 200 a pop. Two more Ecobee tstats, the 24v transformer, and install costs? all to get HS4 integration?

[outbackrob]

Something to consider is the Remotec ZXT-600US. I have a very (VERY) old split system that I am shocked even had a remote, but it has no other app or other interface capability. I didn't think I was going to be able to remotely control it let alone get it to function via HS. Without much more than adding it as a z-wave device, I can control MOST of the functions of my old Mitsubishi. I can turn it on or off, change the temp, change the mode, and change the fan speed. And, it just works. I have had it for a few years now and it is still on the same two batteries. It was the last major system in our house I had to automate and the Remotec made it happen.....

PS: You can still buy them on Amazon: Amazon.com: Remotec ZXT-600 Z-Wave Plus - IR Extender for AC Conditioner : Home & Kitchen

Just for the record, Fujitsu mini splits also offer a 3rd party thermostat option. The UTY-TTRX works similarly to the PAC-US444CN described above. I have 7 mini splits controlled by 6 Fujitsu UTY-TTRX. The fan control is solely by the head unit, and the mini split essentially has two stages of heat and two stages of cool per the thermostat.

My systems are in an Airbnb 2 hours away so the loss of some efficiency is outweighed by the ability to control it remotely.

[jgreenberg01]

Update:

I went with a Mitsubishi mini-split: MSZ-WR24NA & MUZ-WR24NA

The PAC-US444CN-1 board does indeed work as expected and it is being used to allow a Honeywell Intrusion TH6320ZW2003 TStat to operate the mini-split.

The downside is that:

• The remote that comes with the mini-split can't be used to control the A/C - the external TStat does all the work
• Some of the mini-split features may be lost - in my case the Honeywell TStat does not support the variable fan speeds that the mini-split is capable of

The upside:

• The mini-split can be controlled by HS4, allowing for total HA control (potentially minus a mini-split feature or 2, depending on your TStat)
• It can now be controlled anywhere WITHOUT REQUIRING A CLOUD CONNECTION!

My control screen looks like this, and I have total WAF because she really dislikes those little TStat screens, especially when trying to set schedules:

[strikvid]

I have a multi-zone LG and use the HS plugin as well. One head unit is in the garage and the other is in the bonus room over the garage. I've setup a serious of events to monitor and control. vidmate 2019i insta downloader

[BeachBum]

I have an MXZ condenser with 5 MSZ wall units. I purchased 5 PACs and 5 Ecobees to automate each zone, but so far only have 2 zones installed at this time. I can tell you a few things:
- Don't use the remotes if you have the PAC installed on that wall unit. I can confirm - in my experience - they do not work together properly.
- I do use the remotes on the three zones that do not have the PACs installed yet. They work.

Overall, Ecobee/PAC works - mostly. I am having one problem that I'm still sorting through, I don't think it's related to still using the remotes on some units. I believe it's related to how the Ecobee is configured & PAC switches are set.

When it is first turned on everything works as expected - heating/cooling starts, if setpoint is not reached, stage 2 kicks in, setpoint is reached and it turns off. All fine and good. It's a vacation beach house & it experiences extreme temperatures both hot and cold, and the unit is a bit undersized. The problem - if it is very hot or cold outside, the unit struggles to reach setpoint and runs for hours. It drops back to Stage 1 after several hours, and then it will definitely never reach setpoint. I have not been able to pinpoint how long it runs at Stage 2 before 'resetting' to stage 1 - this happens overnight, or during the day while we are not home. Turning all units/stats to OFF, and then turning them back on solves the problem. It works as expected, with Stage 2 kicking in properly.

Since it's a vacation home, it has not been a priority to figure this out, but I'm working on it. I suspect DIP switch settings on the PAC may correct this problem.

[jgreenberg01]

I'm still working my way through this, but has anyone actually used the PAC-US444CN-1 interface with a Mitsubishi mini-split?

I'm getting conflicting answers as to whether the RF remote will still work when using an external TStat. The manual has this:


But I've had others tell me otherwise.

This is incredibly frustrating!

[jgreenberg01]

You can install a regular Tstat for most split units. Check your installation manual for details.

This is not what I am finding. My recycle bin is full of downloaded installation manuals from various manufacturers that make no mention of connect external TStats.

Through speaking with the good folks on this forum, as well as the HVAC vendors my company uses to install the units in the homes we sell, I have only identified 2 manufacturers thus far that will absolutely do this.

They are: LG & Trane (Mitsubishi).

There are lots of manufacturers that will allow a "smart TStat" connection through wi-fi, which is what I specifically do NOT want to do. I am trying to avoid getting into a situation where the only external control is through a cloud service.

If you do know of another brand that does this, I would be grateful if you would share.

For now though, it will be LG or Mitsubishi, depending on what discounts - if any (there's some advantages to being in the new home biz!) can get me.