Three speed whole house fan

I know nothing about mhcozy or every even heard of them. Zooz has some great devices/firmware and has custom device handlers for each of their devices for a variety of home automation platforms including SmartThings. I try to stick with devices that are well supported as I have had some nightmares in the past with random devices doing things they are not supposed to.

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I totally get that

I wouldn’t have had any experience with MHCOZY if it weren’t for the application that I needed. name sounds a bit too feel-good, heheh


But it’s been solid for several months, and has some notable differences, with it being Zigbee 3.0, with repeating capability, and the relay config options.

I can recommend it, for what that’s worth.

Good to know. I have like 3 zigbee devices and 40+ zwave devices so I have been trying to keep to zwave where I can. The Zooz also has a bunch of customization that sounds familiar to the one you are playing with. Once you have the custom device handler loaded all of these settings are available under the master device.



Very nice
 It does have me interested to know what those “switch type” options do.

Zooz’s handlers are second to none. The Zen16 has been on my list to buy for a while, I’ve just been heavy on Zigbee lately. I’m sure it will swing back toward Z-wave at some point.

James, here is what the switch type settings look like.

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I have the quietcool setup that uses two separate physical fans. The top switch is on-off for the low-power fan, the bottom switch is low-high for the high-power fan.

We only really use low (LP fan off, HP fan on low) and high (LP fan on, HP fan on high). There are various settings available by mixing off low and high with the two fans, though. I was thinking of two separate on-off smart switches to power the LP fan (“low”) and the high side of the high-power fan (“med”), and that would turn them both on for high.

I have a lot of smart switches lying around needing jobs, and this seems like a pretty simple way of getting low, med and high.

I am not an electrician, and before reading this thread I was considering putting a dimmer on the high side of the high power fan, but now I’m guessing that is a bad idea?

I know this is an old thread, thanks for any and all input!

Correct. The physics for a dimmer that controls lighting is very different than the physics for a variable speed motor, and you can end up burning out the fan, the dimmer, or both. Instead, you need to use a switch which is specific to motors.

The following FAQ is old but still valid, because, well, physics. :wink:

Automating Fan Control--Don't Use a Light Dimmer!

I love this solution but I’m having trouble with the wiring between the SPDT and Zooz. I have a pretty good idea from the picture you posted but I’m not sure what’s going on left side of the SPDT and into the Zooz. Any chance you have a wiring diagram? Appreciate any help.

Timothy, Just saw this. Do you have two separate quiet cool fans or just on that is 2 or 3 speed? The 2 & 3 speed ones are a single fan motor that is multi speed and needs to be treated that way and only powered exactly how quietcool’s switch setup powers it. With how I have my Zooz & SPDT relays setup there is no physical way I can power it any different than how quietcool’s switch powers it. As for a dimmer, JDRoberts is right, do not run a dimmer or you are going to most likely burn up a very expensive fan motor. Good luck!

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farhad-a,
If you go back to my posting of the quietcool wiring diagram I had early in this thread, you will see the two switches that ship with their 3 speed fans. I am using the two relays on that board to replace the two switches like for like for the quietcools switches that ship with their 3 speed fans. If you have a two speed this will be similar but a little simpler of a setup. The zooz has 3 on/off relays and to emulate the two single pole double throw switches (SPDT) I had to use those two external SPDT relays hooked to two of the zooz ports. I use R3 interface on the Zooz to replace the quietcool timer directly as that is just a single pole switch so that means my 120v that feeds into the relays is only on if R3 is turned on, exactly how the quietcool timer is wired. I then use R1 and R2 to control the two relays. The relays are low voltage and the Zooz needed a power source so in picture of my box in the lower left you will see a small DC transformer. I forgot right now if its 5vDC or 12vDC but what ever the Zooz needed I bought relays that used the same voltage. I then hard wired the DC negative to both relays and then ran the DC positive off the tranformer to one side of R1 and one side of R2 and then the other side of R1 and other side of R2 ran to the coil on each relay. The 120v side of the relays I wired exactly the same as the two quietcool switches. One other thing is that I was having reception issues with the Zooz in a steel enclosure so I ended up cutting a plastic cover for the top of the box and its been working great July of 2020. I have two seperate 3 speed quiet cool fans in the house, one for our upper attic and one for our lower attic and they are used almost every night from the middle of spring to the middle of fall and have been awesome. The wife and kids just use alexa to turn them on and off as needed but I also have an auto off setup in ST to turn them both off at 5:30am in case we leave them on all night. Please let me know if you have any other questions.

Awesome. I think I got it. Your details helped a ton on the DC side. Does this look right?

I was going to start on the virtual switch, but wanted to clarify if relay 3 needs to be on for the high setting?

If you turn on relay 3 (without changing the dimmer percentage) does the fan start on the last speed setting?

Good to know on the steel enclosure. Haven’t ordered one yet but will look for a plastic one.

I just had a quietkool house fan installed and it’s three speeds and is amazing.
I asked the installer why no smarthome connection?
He said it was a safety regulation as there were many people who used automation to turn the fans on but doors and windows were closed and the fireplace was on . apparently the fan sucked smoke and soot back into the house endangering the occupants.
He said so the quietkool folks made it manually operational only.
I’m also looking at the robotic fingers to press the buttons.