120v Relay for fan control wire

Thread Starter

Subwoofer

Joined Mar 2, 2024
7
Hello all,

First post here, looking to lean on some expertise here.

I have a Pansonic bathroom exhaust fan FV-0511VFC1 with a control switch. No power is to be supplied to the control switch. I have a wall mounted Lutron switch, that is supplying 120v, hoping to use this to control this line. Since I cannot supply power, I am hoping to use a relay that once the Lutron switch is turned on, completes the loop on the control wire. There are many relays out there on the internet, and with limited knowledge, I am not clear on what I should be looking for. Any guidance is appreciated.

Panasonic manual - Pg 5 for wiring diagram: https://ftp.panasonic.com/ventilationfan/whisperfitdc/wfitdc_vf1_vfc1_en_install.pdf
 

nsaspook

Joined Aug 27, 2009
13,265
Can't you just connect the two control wires together with a wire-nut or something and just use the wall mounted Lutron switch if you don't want remote or external fan control?
Are you asking about some sort of remote control (to activate a relay) of the fan using the control wires?
 
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Reloadron

Joined Jan 15, 2015
7,515
OK so here is what you have:
Fan Samsung.png

I agree as to just tie the two red wires together. They are designed for dry contact closure. You can add another switch or just tie the two red together so when the powerswitch is closed the fan will run.

Eon
 

Thread Starter

Subwoofer

Joined Mar 2, 2024
7
The control switch is an optional feature on the fan. If the two red wires for the control switch are connected, the fan will run. IF they are connected with a wire nut, the fan would always run and this is not the goal.

I want the action of the the Lutron switch turned on (120v power signal) to complete the circuit of the two red wires. I assume a relay would help me with this, but am not entirely sure.
 

nsaspook

Joined Aug 27, 2009
13,265
The control switch is an optional feature on the fan. If the two red wires for the control switch are connected, the fan will run. IF they are connected with a wire nut, the fan would always run and this is not the goal.

I want the action of the the Lutron switch turned on (120v power signal) to complete the circuit of the two red wires. I assume a relay would help me with this, but am not entirely sure.
Show us the connection diagram you think you need and the one you have if this is a retrofit. Are you saying the 120vac power to the fan is hardwired to the fan without an existing wall switch?
 

Reloadron

Joined Jan 15, 2015
7,515
OK, per the above schematic, with the two red wires joined using a wire nut or taped or any which way they are joined then when the "Power Switch" is turned On the fan will run, when the power switch is off the fan will be Off. So having a relay energize when the power switch is On and the Normally Open contacts of the relay close connecting the two red wires together yes, the fan will run. So what is the point of using an additional relay? That is what myself and nsaspook are questioning. Can it be done? Sure but why?

Ron
 

Thread Starter

Subwoofer

Joined Mar 2, 2024
7
here is the practical answer on the why

the power switch will always be on, as the fan will turn on when humidity sensor is triggered

the control switch allows the user to turn on the fan for "as needed" use, say when someone is using the bathroom and wants to vent the room.

in an ideal world, I would not need a relay in between Lutron 2 and the red wires, and could just connect them directly. unfortunately, the Lutron 2 I am using is a dual switch and there is only one input wire. I don't have space to separate the dual switch (1 gang) in to two separate switches (would require 2 gangs)
 
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nsaspook

Joined Aug 27, 2009
13,265
here is the practical answer on the why

the power switch will always be on, as the fan will turn on when humidity sensor is triggered

the control switch allows the user to turn on the fan for "as needed" use, say when someone is using the bathroom and wants to vent the room.
That sounds logical. What is Lutron 1 in your diagram? That looks like a AC power switch of some sort.
Anyway, a simple 120vac relay like this should work for your relay function.
https://www.amazon.com/ABXLNIU-High-Power-AC120V-Connect-HF105-8X/dp/B09TRDY9DH/ref=sr_1_4?crid=1UNXO0JHD3DIM&dib=eyJ2IjoiMSJ9.mUDNdNEP0Yv21U8JsS9--gnuqRdLiqBI_Cw006_qyd9x4nUPj-N8yJHx8sXxiBl8Maf6_jpbaWp5azenEweowsmV3WyMvJ0H7XlWVvg8PA0coNzY8EFC9tEoayfeTrhsV4bVf2fqVRUCDtNg7q9yZp8DtgZIQzuDohcZ1W10fbKdV3S0KAR7XBoHLOcopz_pdxWswaVwBoFDz0HxV8MvNWkvqkwsPVcGaj-9h_CRJR0.yYqUrAGQ_fMXVJR6nvJSH8Va6yXeDwG9EGHDAuViTbI&dib_tag=se&keywords=120vac+relay+spst&qid=1709420968&sprefix=120vac+relay,aps,144&sr=8-4

1709421249756.png
 

Thread Starter

Subwoofer

Joined Mar 2, 2024
7

nsaspook

Joined Aug 27, 2009
13,265
As a note to those needing help, not this one as it was pretty good and quick. Please include as much information about the application details as possible, in the beginning.

This is a perfect example of why most young think old people are slow thinkers. When old guys see a question like this, they see a large number of possibilities gained from experience. Those with less experience only know a few or the single application they need help on. So IMO they get often get impatient when questions are asked to narrow the possibilities for a good answer.
 

nsaspook

Joined Aug 27, 2009
13,265
lutron 1 is just a switch for the power switch. it supplies the power to the fan.

thanks for your help. To confirm, the recommendation is something like 120v ac spst relay. this will not move any power between the two circuits, right?

the one above is out of stock. here is another I have found:
Tnisesm 2PCS Power Relay SPST(1 NO) AC120V Coil, 30A SPST 120 VAC with Flange Mounting and 8 Quick Connect Terminals Wires Mini Relay HF105F-4-AC120V-8X
Yes, it should work to provide a dry-contact closure but take notice about the pre-crimped connection wires. In your dry-contact application, the wire sizes won't matter but if the contacts are used to switch hot AC power loads, it will matter.
In this product, the included wires may seem confusing, since all 3 black ones look alike but are not. Only 2 of the black wires are large, and have the large connectors which fit the higher power connections to the relay contact. The red and other black wires are smaller, having the smaller connectors which fit the lower power connections to the relay coil.
 
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Jon Chandler

Joined Jun 12, 2008
1,049
the power switch will always be on, as the fan will turn on when humidity sensor is triggered
It's the little insignificant details that get you every time. You know why you want the fan powered all the time, but no one else does, and then you get frustrated and argumentative with those suggesting the obvious solution given the lack of critical details.
 

MisterBill2

Joined Jan 23, 2018
18,464
The wiring diagram is not very useful as I suspect that the "control switch" may be more that just a switch. There is certainly some reason, undisclosed, as to why switching the mains power on and off is not specified.
So IF the TS has a multimeter able to measure resistance, the plan will be to measure the resistance between the control switch with the switch in both positions. That should be done before connections are made to anything. Then we will learn just what the switch really is, I suspect it is more than is shown. Or maybe not.
 

nsaspook

Joined Aug 27, 2009
13,265
The wiring diagram is not very useful as I suspect that the "control switch" may be more that just a switch. There is certainly some reason, undisclosed, as to why switching the mains power on and off is not specified.
So IF the TS has a multimeter able to measure resistance, the plan will be to measure the resistance between the control switch with the switch in both positions. That should be done before connections are made to anything. Then we will learn just what the switch really is, I suspect it is more than is shown. Or maybe not.
The problem has already been solved and the reason for the "control switch" in this application is clearly understood. Nothing is undisclosed now. It just took a bit of Twenty questions to get there.
 

Thread Starter

Subwoofer

Joined Mar 2, 2024
7
Thank you all for the help.I was able to install the relay and am now able to use the control switch function of the fan. The only downside thus far is the relay does have an audible "click" when the switch is pressed.

For information, I did test the signal wires with a multimeter in the following positions:
When the main switch is off, the signal wires show 0v and have almost no resistance 5 @ 200k
When the main switch is off, the signal wires show 120v and have some resistance 35 @ 200k
 
Last edited:

nsaspook

Joined Aug 27, 2009
13,265
Thank you all for the help.I was able to install the relay and am now able to use the control switch function of the fan. The only downside thus far is the relay does have an audible "click" when the switch is pressed.

For information, I did test the signal wires with a multimeter in the following positions:
When the main switch is off, the signal wires show 0v and have almost no resistance 5 @ 200k
When the main switch is off, the signal wires show 120v and have some resistance 35 @ 200k
I like the old school 'click'.
You did ask for a relay (a electromechanical device) ;). If it's mounted on metal or another surface that acts as a resonator, a rubber/rubber grommet wedge for sound isolation and some spray sound damper (over the protected reay and wires) might help.
1709589529626.png
https://www.aervoe.com/product/undercoating-and-sound-insulator/

Or you could just use a quieter relay. :D
 

Thread Starter

Subwoofer

Joined Mar 2, 2024
7
Out of curiosity, and for my knowledge, how would you find a quieter relay?

I probably will not end up changing it, as this project has run its course and time to move on the other things (My future post will include more information );) At least the click will be a good indicator, in the event I need to troubleshoot something in the future.
 
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