Does this seem like a workable solution to controlling my AC?
I have the ability to solder in some dry contact relays into my AC that will allow me to turn on/off particular zones (one relay per zone). It's a 12/yr old Mitsubishi Heavy Industries system with no ability to be connected (I've tried every possible route).
My initial thought was that I would then get temperature sensors in each zone, set the AC to be at the coldest setting and then turn on/off to maintain a particular temperature.
Then I hit on the problem of how would a member of my household change the temperature? So I'm considering a Zen Thermostat in each zone. I'm thinking that I could set a variable called something like "BedroomTemp" and have the Zen adjust this variable so that my rules would then adjust as per the chosen temp in the thermostat, turning the AC zone on.off to maintain temperature.
Does this all sound viable? Is there an app that would handle all this?
I then want to voice control the thermostat from Nest Hubs but I can't see that the Zen is compatible, but the Ecobee device is, is that a better thermostat? Will I be able to say "ok Google, set temperature to 24" and have it adjust the ecobee which sends that number to HE and then have my rule adjust using that as it's variable?
that does sound cool. You're definitely blazing a new path. If you're confident about being able to make the changes without compromising your unit, then blaze that trail. Look into rule machine to make things happen. I'll be following your project to see how you turn out. Definitely be careful and slow so that you don't compromise your unit in the process.
The soldering is just at each existing wall mounted remote control (which I'd then have to hide or relocate) and they cost just $100 each, so not too risky.
that's TWO switches. That's risky to me. But when you know what you're doing, probably doesn't worry you. Right? Piece of cake when you have the knowledge.
I was planning on using the thermostats unconnected to my ac but connected to HE, they will just take the inputs from touch and voice and sending to HE to then turn on and off the zones to maintain temp.
I would be careful giving Alexa and/or HE full authority of the temperature. I personally don't feel the current level of automation is reliable enough to rely on it to not send your A/C into the meat locker mode. But I guess its safer than controlling the heating system.
Does the thermostat shown act the same way as a normal wall thermostat? If so you can get one of the Smart thermostats as a replacement and control that. The authority limit is in most if not all thermostats, limiting the extreme settings.
If you end up soldering wires to your current wall mounted control (thermostat?) Be careful about how long the wires are from your relay to the tstat. Internal connections are not designed to deal with the electrical noise and ESD that could come in on wires reaching outside their housing.
Sorry to sound so negative but that's how my mind works.
This is where I’m having trouble understanding how OP’s A/C setpoint is controlled. I’m inferring there are no thermostat wires because then, as you said, it would be a simple matter of replacing with smart thermostats.
@bf1 it might just save time if you shared the model # and/or specs of your A/C.
A solution that involves several WiFi-connected thermostats, none of which are actually wired to your HVAC system, seems awfully Rube Goldberg...
I'm not getting it either. I do have a regular z-wave thermostat, which is controlled using input from 8 zigbee temperature sensors. I'm not sure why I'd want to replace the temperature sensors with unconnected thermostats.
That is an RC-E5 wired remote. The wired remote is connected to the indoor unit by a two conductor wire... This connection at the indoor unit feeds into the IR Remote control circuitry after the IR receiver/ signal amplifier... The system is (almost) literally a remote control transmitter/receiver with wires in place of the IR emitter and IR receiver.
This wired remote is an optional accessory... The primary control is a wireless remote control... These units operate in exactly the same manner as a mini-spit or portable AC system...
A less destructive path to integration would be a Broadlink RM Pro or RM3 Mini and the RC HVAC application that I have in BETA... HERE
It has no inputs for control, no IR or an method, it's serial control. Nest, Ecobee are not compatible (clarified with them). CoolMasterNet isn't compatible and there are no Mitsubishi boards to convert to ethernet control.
The devices:
It's a VRF system, the indoor units (evaporator units) are 3 x Mitsubishi FDUMA112KXE5R, the outdoor model is a Mitsubishi FDCA450HKXRE4BR.
It also has a controller to control each individual controller:
I've been told "not compatible" by a lot of people/companies/aftermarket products manufacturers but i'm happy to hear otherwise. It's a complex, 12 year old system that would cost $30k AUD to replace with an equivalent today (I believe).
The technical manual says that the wireless remote unit is an option on the FDT series of indoor units (page 501)... and that the Wired Remote control is optional (Page 259). This would imply that the receiver is included as standard in all models except the FDT series. Except that the manual also says (page 505) says that the wireless receiver can't be used on a cooling only system.... So your installer may not have installed the IR receiver... (I have actually just found a KX4 brochure that indicates that both wired and wireless are optional)
You have the SC-SLN1-E centralized controller... which indicated that your system has the superlink or superlink II controller... (Which also means that the wired remotes could be RC-E1R instead of RC-E5)... This means that it is compatible with the SC-WGW-AR/SC-WGW-BR Web gateway which provides control and monitoring via an ethernet connection OR the SC-WBGW256 Web and BACnet gateway.
So... There are plenty of interface options (besides cannibalizing a controller)...
