Leviton LTB60-1LZ bathroom fan Z-wave control

The LTB60-1LZ Leviton bathroom fan timer is an awesome addition to you bathroom. It would be really nice to add the ability to start it (or stop it) with the home automation as in my case, the fan and dimmed lights turn on when someone enters the room (who wants to be blinded when they have to go in the middle of the night?). It could also be triggered by temperature or humidity and there is no sacrifice of the manual timer functions.
LTB60-1LZ_a

There is a remote control wire that is designed to work with their Vizia+ Coordinating Remote Switch. The company would not reveal the technical information for designing your own remote switch input. So, the simple solution was to purchase a remote switch and disassemble it.

You add the remote feature by adding a simple Z-Wave relay with a 2K ohm 2 watt resistor from the remote wire of the timer (yellow/red wire) to the neutral (white wire in you box). I used the Qubino Z-Wave Plus Universal Relay with Dry Contact Switch ZMNHND3. Works like a charm with the addition of a temperature probe. An important note: make sure you program the switch auto off to 2 seconds or less. You don't want to leave it engaged for any longer.
wiring4

I added a Zigbee SmartThings button near the commode just in case the timer runs out before you do.

1 Like

This has been a "round-to-it" project for me. I've had the LTB30-W, the resistor and an Aeotec Nanoswitch sitting in a box wait for me to get to it. After doing some poking around, I've also ordered the Shelley RC snubber.

How does one safely wire in the resistor? Should the exposed wires be heat shrinked?

Yup

1 Like

Follow up question(s)
.... is the snubber even needed with this setup? Or is the LTB30 switch acting as such?
.... and if the snubber is needed, where to a wire it in on this circuit?

@csteele your .02ยข would be appreciated.

OK, here goes ... :slight_smile:

An RC Subber is sold as targeting an Inductive load, such as a motor, fan or otherwise. And that's the topic here, so yes, I'd include it because it's protecting the Aeotec. A large enough back emf current surge can weld the relay contacts inside the Aeotec.

Another "YUP" for heat shrink.

1 Like

I am not sure if the Aeotec Nanoswitch is a simple contact relay. The instructions don't look obvious to me. There is no other snubber or anything else needed as the power does not run through your added relay contact. In fact, there is no place to place a snubber. This setup merely signals the timer to fire the previous setting. Be sure to program the trigger to turn on the relay and turn it back off within about 5 seconds (Mine is set to 3). I enclosed the resistor and wiring in heat shrink. The 2k ohm resistor could probably even be a one watt or a variation of values between 1.2K and 5K. I just used the 2K resistor I took off of the satellite switch I purchased to determine how to wire this.

It is important that the relay wiring you are hooking into the timer is only a switch and no common connection to the line power. I looked for the words "dry relay" in descriptions to determine what to use.