Does SmartThings work with RedLink?

It is my understanding that both Z-Wave and RedLink communicate at 900 MHz. If so, can a RedLink thermostat be discoverable and configurable by my SmartThings hub.

Zwave doesn’t communicate exactly on 900 mhz. It uses 908.4 in the US (and a different frequency in Europe), but it also requires messages in a specific format as certified by the Zwave Alliance.

Redlink is a proprietary messaging protocol from Honeywell. It hops around in the 900 band, but specifically tries to avoid the zwave frequencies to reduce possible interference.

So the two are not able to communicate.

Here is the list of network protocols supported by SmartThings (from the community-created wiki):

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While not supporting Redlink directly, there is a community device type that connects to any Honeywell thermostat that uses the TotalConnect website. A quick search of this site will find it.


Do you have a specific thread to link to? For the Redlink version, I’m only seeing threads where the device type was never released because a significant percentage of people had problems with it. It would work for some people but not others. So still considered in beta. But maybe there’s one I missed.

My thermostat’s are the 9421’s, but as I understand the devicetype ANY Honeywell thermostat that connects to the Total Connect Comfort website will work: Honeywell Home - My Total Connect Comfort

Here is the link:

My thermostat is a Mitsubishi MHK1. It is specified for my Mitsu Mini Split HVAC but looks just like the Honeywell YTH6320R1001 and since it is RedLink enabled I assume Honeywell private labels it for Mitsu. It seems that most of the links on the topic of Honeywell Thermos are for WiFi enabled units. I’m not sure that is the same as RedLink.
Thank you for your information. I haven’t gotten the thermostat yet, but when I do, I’ll see if it is discoverable. Based upon your research it seem very unlikely it will work.


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It has to connect to the Honeywell site, otherwise it won’t work.

If you are a coder, there is a Redlink driver manual that implies that you can write a driver for it, but it probably involves getting API access and no mortal on this board has been able to get that. I never even received a response to my request.

I saw that thread, but based on the comments in the last month it is only a partial integration for any of the models that have automatic scheduling. The automatic scheduler, which most of the redlink models have, conflicts with the settings from the smart things smartapp. So people do not get the results that they want.

Those people who just set the thermostat like it was a dumb thermostat to a single value and then use SmartThings to change it to a different set point value later probably find it very useful, but I wouldn’t say it was a real integration Yet even for those using the Honeywell cloud service.

Brian, I’m not that technical. It is not critical to drive this thermostat with ST. I had to buy this unit and it happened to come with RedLink so I thought I would try to have them “play together”. Thanks for the help

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It works awesome for me, and I do disable the scheduling. It’s actually what brought me to ST in the first place, this community devicetype. My stats are very smart now especially with Rule machine. :smile:

Hi Brian,

So you’ve had success with SmartThings and thx9421? My contractor is recommending this thermostat but i’m hesitant to get it because i want integration with SmartThings. Why do you disable the scheduling?


Because I use motion and presence detection to run them completely. Times are useless with my family, we don’t have a regular schedule.

Small example. Three floors. When we are all not home, heat is 60. When we are home all heat is 64, and the floors that have motion are 66. The heat follows us around.

When on vacation heat is 55. BTW I use auto so I set cool too.

At a certain point you have to ask just how much energy efficiency is to be gained from automation? I’m all in favor of gizmos (else I wouldn’t have ST and others) but do have to question how much dependency on automation is going to result in genuine benefits.

How are you defining ‘away’ and how does that factor with recovery times? As in, how soon does your system fallback and how long does it take to recover?

I’m seeing problems going with sensing alone. If only because of dealing with the amount of time it takes to bring the rooms back to comfortable levels. I’m using a combination of schedules and presence. If only to allow for when scheduled activities aren’t taking place. Like the cleaning lady not coming on Wednesday, but Thursday instead.

But then apparently not as tight-fisted. 66F? Yeesh, that’s too chilly for me!

Cut my heating bill in third (with some other tweaks). I’m an energy efficiency nut.

Away is when no one is home via presence or vacation mode. It’s rock solid with my system. I have geothermal, so recovery is long. But I find that if no one can see the temps, they feel warm because warm air is blowing right away.

Due to the way furnaces work, you almost always save if you setback for any amount of time. Has to do with rate of heat transfer.

In any case, sweaters and blankets are cheap compared to oil, gas and electricity. And better for the environment too.

Hi guys!

Part 1: I have a minisplit HVAC system from Mitsubishi which is designed to works with their MHK1 (you cannot hook up a smart thermostat wired to it such as the Honeywell RTH9580). I do, however, have the Redlink gateway which is supports, and I can control the thermostat from the Honeywell website and iOS app.

What I want to do of course is control the thermostat using SmartThings and integrate my own rules for when and how the minisplit system operates. I was reading about the CT100 Z-wave thermostat. If I get that, will I be able to essentially replace my MHK1 with it and have Z-wave control? Any info you can provide would be greatly appreciate.

I understand there could be limitations about scheduling, but I don’t need to use that feature of the thermostat as I will do this all via ST and rules and my own occupancy sensor rules (motions, door open/closing etc).

Part 2: On a related note - I also have a dedicated whole home humidifier that I want to control via ST. I already have it set up so that the dehumidifier will turn on / off via a simple relay, and I have a working ST device that I can send a signal to to have it open/close the relay. What I am missing is a smart humidistat control. Basically I need a control to report the humidity in the room so a ST rule can signal my relay to open/close for when I need dehumidification.

What is the best ST compatible humidistat for that? If the answer to Part 1 is that I can use the CT100, then I think that has a humidistat and I could leverage that for this purpose? But if not, what other RELIABLE humidistat is there (seems like the CT100 would be overkill for just this purpose if it turns out the answer to Part 1 above is that I can’t use it to control the minisplit).

Thank you!

Part 1. As much as I love my CT100 to control my separate heating zone, Mitsubishi requires freakishly expensive Mitsu thermostats because of all kinds of control and diagnostics that is handled by the stat. For my minisplit zones controlled by the handheld IR Mitsu controller I used a Remotec Z-Wave ZXT-120 IR Extender for Air Conditioners. This puts out a IR signal (which has to be programmed like a TV remote) to turn on and set temps by SmartThings. It takes a bit to find the appropriate IR code but once done you can change the mode, fan speed, temp, etc.

Part 2. I have a nice humidistat setup using smart apps from RBoy ST, a great site for smart apps and device drivers. The CT100 will give your the humidity measurement you need but as you say may be overkill. In my particular application I used SmartThings SmartSense Temp/Humidity sensor. I use this in a basement storage room that I want to turn on switched outlets for my humidifier or plug-in heater based upon the temp or humidity during different seasons.

Good Luck.

Thanks Paul! Some follow up questions please:

  1. I already have the MHK1 for config/diag, but I don’t want to use it to control the HVAC. Instead I’d like to use ST… Since this minisplit does work well with Redlink and the Honeywell app, is there a way I can use the CT100 (or some other way) to have ST talk to it by interfacing with Redlink?

  2. The Remotec sounds great. How does it work essentially? ST sends a signal to Remotetec that says “set fan to low” and then Remotec sends the signal to the minisplit itself or to the MHK1? I would think it sends it to the minisplit? If it does, that means the MHK1 works off of IR?? If that’s the case I was not aware of it and have no idea how its using IR to go through walls to talk to my minisplit unit?

  3. When Remotec sends the signal to change something like the fan speed, does the MHK1 refresh itself to indicate the new setting?

  4. Regarding the ST SmartSense Temp/Humidity Sensor - is that still a current product? Amazon says out of stock and no replenish date, and searching the web head to toe I could not find it for sale anywhere.


I have a Mitsu 3 zone system that has 2 mini split wall units controlled by individual handheld IR controllers and a ducted zone that is controlled with a wired PAR-31 MAA Controller. I tried the MHK1 on this zone with no luck. I ended up selling it on Ebay. MHK1 does NOT work on IR.

The Remotec is a “dumb” IR controller. It will send out the equivalent IR signals that the handheld (HH) controller does. It does not control through the HH so if the HH turns the wall unit off and the Remotec then turns it on or changes the temp, the HH still thinks the unit is off. You can use the HH to override the other by cycling through some commands.
I have found that the Remotec will give you the current mode, temp and set temperature if you send a refresh command.

I also thought the SmartSence Sensor was discontinued because it is not on Amazon but it is offered on the SmartThings website today.

Thanks. So since my minisplit can only be controlled via MHK1, and that doesn’t work on IR, then I assume I cannot use the Remotec right?

In which case I guess that leaves my original question - which is whether it is possible to use ST to talk to the CT100 to talk to Redlink to control my minisplit…?

I do not know if this helps, but if you are going to to the Total Comfort website to control your thermostat right now, in theory the device type that interfaces with that would work.

There are so many things that could stop you, I don’t want to get your hopes up too much…