VZM35-SN cannot turn off Delta BreezGreenBuilder GBR80H

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I’ve got a few of these Delta BreezGreenBuilder GBR80Hs in the bathrooms of the house. They are AC exhaust fans that have a humidity sensor that can be used to control the fan. These were installed by the builder when the house was first built ~10 years ago. There are two ways to wire these fans:

  • With a single switch, as explained in the Single Wall Switch Set Up.

    • In this setup, either the switch or the humidity sensor–when humidity is above the threshold–will turn the fan. But the fan only turns off if both the switch are off, and the humidity is below the threshold–with a timeout.
    • This is the setup I have.
    • For posterity, the wiring diagram looks like this:
      wiring diagram of single wall switch
      wiring diagram of single wall switch1480×1978 387 KB

  • With two switches, as explained in the Installation & Operating Manual.

    • In this setup, the “power” switch turns the fan on, and the “mode” switch makes the humidity sensor control the fan–above the threshold the fan is on, with hysteresis.
    • I don’t really know the behavior of this setup, because none of the fans are wired this way.
    • For posterity, the wiring diagram looks like this:
      wiring diagram of two wall switches
      wiring diagram of two wall switches1282×1438 77.9 KB

These fans have worked fine: when it’s humid, the fan comes on; if you flip on the switch, the fan comes on; if it’s not humid and you turn off the switch, the fan goes off; if it’s humid and you turn off the switch, the fan stays on until it’s below the threshold.

I just tried to install a VZM35-SN on one of these fans, and I cannot turn it off.

  • The switch is using the neutral wire.
  • The line is going to the line of the switch.
  • The “blue” wire from the fan–which is actually red in my house, because it’s normal Romex 14/3 wiring–is going to the load.
  • The settings in Zigbee2MQTT are:
    • “SwitchType” came as “Aux Switch” when I paired it, so I changed it to “Single Pole.” No difference.
    • “SmartBulbMode” is “Disabled.”
    • “OutputMode” is “Exhaust Fan (On/Off).”
    • “PowerType” is showing “Neutral.”
  • The only thing that works to turn the fan off is pulling the air gap (which is a non solution).

I saw this thread: White Fan Switch Load Always On, which is about a VTM35-SN, not a VZM35-SN. But since pulling the air gap works, I assume it’s not the same issue.

I saw this thread: Blue Series Fan Switch Load Always Hot Even When Smart Mode Is Off, where the solution was to update the firmware. This switch is on firmware 1.08, which seems to be the latest version.

I saw this thread: Blue fan switch - smart bulb mode always on (I don’t know if a Zephyr and a VZM35-SN are the same model) where the solution was to manually disable Smart Fan Mode. I tried that, but no difference.

I saw this thread: Inovelli Blue fan switch won't turn off(smart fan mode disabled), where the suggestion was to factory reset it. I tried that, but no difference.

As far as I can tell, this should be behaving like a regular on/off exhaust fan. But it’s not. It’s like it has constant connection from line to load. I’ve installed two other VZM35-SNs so far on AC ceiling fans, and those have worked okay. So I at least know that when it’s a plain old AC fan, I can wiring these VZM35-SNs up properly. But I’m pretty stumped on this one.

Will the VZM35-SN not work on this fan because of its wiring setup? Or is this a firmware issue that I’m not setting up properly? Has anyone run into a similar thing before (maybe on a different fan)? Am I using the wrong switch entirely? Should I be using a VZM30-SN? The GBR80H says it consumes 12 Watts, which seems way under the 1800 Watt rating for a VZM30-SN. Or, would it not make any difference and/or the VZM30-SN isn’t rated for exhaust fans? Any other thoughts about what might be the issue?

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This is just a guess, but I think you should be using a VZM30-SN ON/OFF switch. Looking at the manufacturer’s diagram, the switch specified true On/Off switch that simply makes and breaks a connection. The Fan switch isn’t a true On/Off, even in the Exhaust Fan mode, and that can be fooling the fan’s circuitry.

So I can’t be certain it’s the fan switch, but if it were me, I’d try a true On/Off.

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Interesting. Is it related to what you explained here: Is the upcoming blue on/off better than the fan switch for exhaust fans? - #10 by Bry? Can you say any more about that? I’m kind of curious why it can work for the ceiling fans then. I guess maybe because they take more energy to rotate, the little bit of trickle that comes off the switch isn’t enough to rotate the motor?

I guess in that regard, I wonder if a Bypass (or in my case, a Lutron LUT-MLC) would also be an avenue? If it is the switch trickling, that ought to soak up the trickle and keep the fan off. Or maybe I’m completely misunderstanding it.

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@jones3.hardy The OP’s question is why the fan switch is not working properly with the fan’s On/Off logic controller, since turning the switch off does not result in the fan turning off, even though the humidity level is below the off threshold.

The manufacturer’s schematic specifies and on-off switch, so the smart switch equivalent would be the Inovelli On/Off, as that is a relay-driven switch, which the fan switch is not. So the equivalent smart switch would be the first thing that I would try.

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Yep yep, I’m the OP :sweat_smile:.

I’ll grab some of the On/Off switches (there’s three of these fans, plus some other things around the house that can’t be dimmed). Was just looking for some more insight as to how it works. No worries though, you pointing out the fact that it’s not a relay is more than good enough for me, and I can go do more research to fill in the blanks. Thanks again for pointing that out! I’ll update this thread once I try out an On/Off switch.

6

Quick update (plus I don’t want this topic to close until I’ve actually sorted this). Using a Lutron LUT-MLC seems to work to soak up the trickle. It’s not ideal, but it works for now. I’ll get a VZM30-SN once they’re back in stock.

7

Alright, I got a VZM30-SN (despite the site saying they were out of stock, it shipped the same day). I removed the VZM35-SN and Lutron LUT-MLC, and put the VZM30-SN in instead. The VZM30-SN works! The fan turns off when I turn off the switch (which seems like a thing you shouldn’t have to say about a switch :sweat_smile:).

@Bry Thanks for pointing out that the VZM35-SN does not work as an actual on/off switch!