Hi Folks,
Anyone have any good ideas or solutions to know when a Mini Split is actually on and blowing air (hot air mostly in my case)? I tried a Samsung multi sensor for vibration, but it chews through the batteries if the vibration is active all the time. Basically my Mini Splits are IR controlled so I only have one way communication, I'd like to be able to have a tile overlay my thermostat tile and have it turn red or say on when the Mini Split is actually functioning.
you could put a relay in (like a shelley) on the 24v line to detect power and use the variable for what you want...
ohhh say what now? The 24 v line going from the inside head to the outside unit? So that would only be live when operating?
Almost the same idea as @rlithgow1.
I would use a current transducer on the neutral conductor of the mini-split. And wire the terminals of the current transducer to a z-wave contact sensor with external terminals.
When the mini-split is on, the returning current in the neutral will cause an induced current in the current transducer that will "close" the externals terminals of the contact sensor. When the mini-split is off, there'll be no current in the neutral, so the contact sensor will register as open.
I do this to monitor when my HVAC blower fan is on/off.
Here's an example of a suitable current transducer:
And here's a suitable z-wave contact sensor:
Here's the event log from my "Contact - HVAC Blower" device that operates on this principle. Works very well ...... (I use split-core current transducers from Functional Devices, but you don't have to).
Be careful with this suggestion, not all mini splits have a 24V line that goes between the inside and outside unit. Some have only 12V and some don't have control lines at all and the power relays are in the head unit with line level control lines going directly to the compressor and fan motors. You need to figure out what you have but it is doable.
Edit: I like what @aaiyar suggests and makes it a lot safer
My thought process was simply to use it as passive not an active relay (so voltage shouldn't matter) Though I like @aaiyar's idea too
Some good ideas, and suggestions. Keep em coming! @nclark yes, I was thinking that and some are digital IIRC. I like these ideas!
Would that be small enough that I could put it in the ac disconnect box I wonder. Easy installation
Should be possible. And use a 1/4" cutout to put the zwave sensor on the underside of the box.
I use 2 SmartThings contact sensors, but any two temperature sensors that also do contact would work. One is at the air inlet, the other at the output.
When the unit is on, the output vanes open. When it is heating, the output is warmer than the input, reverse when cooling. Works perfectly for my needs.
Thats an interesting one too and very easy. Is the battery life ok like this? Do you have a rule written to turn a tile on or do you just go by the temp readings?
I think I have only had to change the battery yearly - it is pretty close to the hub which would help I assume!
I have it integrated within an existing community app as the temp sensors, but if I had to do it without that app, I would have a rule that changes a string to say “Fan”, “Heating” and “Cooling” based on the temperature.
Ahhh right, makes perfect sense, and with that method you can tell what it is actually doing based on real temp input / output.
@Sebastien, did you place one of the temp sensor actually on the moving vane for the output or somewhere different? Maybe in the output cavity inside the moving vane?
Yes - Here’s a picture:
Also, if there is I not enough space for them magnet that comes with, another smaller/flat magnet can be stuck to the insides.
HOT DAWG! That's a really "cool" job, and tucked away neatly. I will give this a go tonight.
Don't think that would work on mine. I have flush mount ceiling cassettes
Ok, so thinking ahead on the application with two temp sensors. My goal is to indicate IDLE (OFF), HEATING or COOLING on a dashboard tile, either by color or by text. Possibly overlay it on the Thermostat tile that it will be monitoring. Does a color changing tile exist based on a rule output? Does a text display tile exist based on a rule output? Any thoughts?
When using (Virtual or Real) Thermostat device and it
Calls for cooling, Tile is Blue
Calls for heat: Tile is Red
I use a custom personal heating/cooling app with five Virtual Thermostats, Ecobee heating only Thermostat device, [Withdrawn] Broadlink App, and Wifi Broadlink Mini3 IR blasters, to control my five mini-splits. My main issue is there are occasional Wifi or IR failures, causing the mini-splits not to turn on or off as requested. I've mostly mitigated this by issuing a second IR command a few seconds after the initial IR command.
Using at least one contact sensor would provide confirmation that my dumb mini-split unit is actually in the requested On/Off state, and could be used to perform command retry n times before sending an alert that the mini-split failed to respond. I would likely use another dashboard tile because the thermostat tile is rather busy. This tile's color or text color could be CSS controlled based on the text's value.
ya i did same thing put cheap zigbee door sensor in vent that actually sends temp and have rules to open close the vents based on the air temp to determine if it is ac or heat.
Download the Hubitat app
