# Exhaust fan interlock



## BBQ (Nov 16, 2010)




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## uconduit (Jun 6, 2012)

BBQ said:


>


That's a *R*elay *I*n a *B*ox, by Functional Devices if I remember correctly


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## BBQ (Nov 16, 2010)

uconduit said:


> That's a *R*elay *I*n a *B*ox, by Functional Devices if I remember correctly


Yes, this one would do it if the wall switch is 277 

http://www.functionaldevices.com/building-automation/display.php?model=RIB2402B 

Or this one if you want to use 120 at the wall switch.

http://www.functionaldevices.com/building-automation/display.php?model=RIB2401B


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## backstay (Feb 3, 2011)

uconduit said:


> That's a Relay In a Box, by Functional Devices if I remember correctly


Comes a lot of ways as far as voltage and switch configures.

I use them for boiler circ pump control.


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## denny3992 (Jul 12, 2010)

How bout 1 fan controlled from 2 different bathrooms? Do they make a unit to do that?


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## backstay (Feb 3, 2011)

denny3992 said:


> How bout 1 fan controlled from 2 different bathrooms? Do they make a unit to do that?


Yes they do. It has two separate relays in one unit.


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## BBQ (Nov 16, 2010)

denny3992 said:


> How bout 1 fan controlled from 2 different bathrooms? Do they make a unit to do that?


I have not seen the one backstay mentioned it sounds slick. 

Other options


1) Wire it all with one circuit and a single pole switch in each bathroom. Wire the switches in parallel and if either switch is on the fan and both rooms lights are on. Simple, safe, but wastes electricity and will make people ask questions.

2) Wire it all with one circuit and a two pole switch in each bathroom. Wire the switches in parallel with one pole of each switch connecting to the fan and the pole connected to that rooms light. If either switch is on the fan will be on and only the light in the occupied room. Still simple and safe. 

3) If the lights have to be on a separate circuit from the fan than you are pretty much stuck with using a pair of two pole relays. (Or the unit backstay mentioned)


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## Rollie73 (Sep 19, 2010)

BBQ said:


>


I use this same relay as well as their CT's, their full wave rectifiers and basically everything they make while doing HVAC controls. They make an excellent product.
Does anybody use their relay with the hand/off/auto switch included in it? One of my favorites for boiler controls.


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## denny3992 (Jul 12, 2010)

I had orig thought relays with interlocks as its 2 -120 sep circuits... And the fan is 120 also


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## backstay (Feb 3, 2011)

denny3992 said:


> I had orig thought relays with interlocks as its 2 -120 sep circuits... And the fan is 120 also












RIbU2C


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## denny3992 (Jul 12, 2010)

backstay said:


> RIbU2C


Thanks, exactly what i need! And my local hvac sh has em!!


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## Wirenuting (Sep 12, 2010)

Rollie73 said:


> I use this same relay as well as their CT's, their full wave rectifiers and basically everything they make while doing HVAC controls. They make an excellent product.
> Does anybody use their relay with the hand/off/auto switch included in it? One of my favorites for boiler controls.


I have installed them so I can bypass the AC automation start. 
I just place them so its not obvious..


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## btharmy (Jan 17, 2009)

I just installed a couple to turn on an exh fan and open a damper when a carbon monoxide detector goes into alarm.


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