# Roof Vent ?



## Hitch Pin (Sep 23, 2011)

Hi To All
We got a 2012 Jayco Swift, and it has a roof vent in the bathroom, but it does not have a fan in it, does anyone know if you can add a fan to this vent without replacing the whole vent?

This vent is next to a light, it would easy to get the power from the light to run the fan.


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## dogbone (Sep 22, 2009)

See if you can get a fan kit from a local RV dealer or a Campers World catalog. It will be a 12 volt system. Put a pressure switch in the vent so that when the vent is raised the fan comes on. You will need to run a wire from the light. You should be able to remove the trim, to hide the wire, and get at the light fixture. I would put an inline fuse in the wire somewhere also.


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## Shadow (Oct 24, 2011)

Depending if you are mechanically inclined, if you don't want to spend the green on a ready made item, you could get a 12Vdc computer case fan, wire it up so it comes on when the light is on, and attach it to the vent.


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## artmart (Sep 21, 2010)

Even if you put in an automatic pressure switch so the fan doesn't run when the vent is closed, you might also want to rig a switch to be able to turn off the fan if you don't want it running at all.


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## dogbone (Sep 22, 2009)

artmart said:


> Even if you put in an automatic pressure switch so the fan doesn't run when the vent is closed, you might also want to rig a switch to be able to turn off the fan if you don't want it running at all.


That is the way mine is set up, Art. I have a separate switch next to the light switch then the pressure switch on the fixture.
I didn't know how much involved the OP wanted to get. They could just put a switch by the fan, getting power from the light and be done with it. Just turn it on and off when they wanted it to run. It might be simpler that way.
Either way I would put a fuse between the light and fan. Shadow had a good idea, using a 12 volt computer fan. Just mount it to the vent trim or bracket.


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## Hitch Pin (Sep 23, 2011)

dogbone said:


> That is the way mine is set up, Art. I have a separate switch next to the light switch then the pressure switch on the fixture.
> I didn't know how much involved the OP wanted to get. They could just put a switch by the fan, getting power from the light and be done with it. Just turn it on and off when they wanted it to run. It might be simpler that way.
> Either way I would put a fuse between the light and fan. Shadow had a good idea, using a 12 volt computer fan. Just mount it to the vent trim or bracket.


I wonder what size the fuse would need to be, I also like the pressure switch idea that Artmart has. I do plan on installing a on off switch.


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## Shadow (Oct 24, 2011)

Hitch Pin said:


> I wonder what size the fuse would need to be, I also like the pressure switch idea that Artmart has. I do plan on installing a on off switch.


Look on the fan label to see how many amps the motor is..

I found a typical fan online with the stats of "Voltage VDC: 12 * Current AMP: 0.4 * Input Watts: 4.8"

So this thing will draw about .4 amps when running. 
The watts is simply 12V times .4amps = 4.8 watts. 

If you are fusing just the fan, I would find a fuse about .5A to 1A. 

You don't want to go under the amp rating or it will blow when you turn on the fan. If you put in too high of a Amp rated fuse, the fan could overload without the fuse burning out to protect it. 

You can find inline fuse holders in auto shops, hardware stores, radio shack, etc.


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## artmart (Sep 21, 2010)

It was dogbone's idea for the pressure switch, I added the inline switch for the whole thing. These are how most rigs come when installed at the factory. There will be a switch or thermostat on the wall to control the fan in the first place, then a pressure switch at the vent cover to ensure the fan is not rotating when the cover is down (this could damage the fan).

The addition of the fuse is important when installing an after market fan and you want to separately protect whatever it is you are adding. Shadow has the best ideas for how to determine what you need. Keep in mind the ratings on the label may not include the surge at startup which is why you would want a higher rated fuse than what the device specifies. 1 amp should do in the example Shadow provided. Never go by the exact rating or you'll be blowing too many fuses. Give yourself some leeway.


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## Shadow (Oct 24, 2011)

artmart said:


> Shadow has the best ideas for how to determine what you need. Keep in mind the ratings on the label may not include the surge at startup which is why you would want a higher rated fuse than what the device specifies. 1 amp should do in the example Shadow provided. Never go by the exact rating or you'll be blowing too many fuses. Give yourself some leeway.


I have an electronics degree and years of experience doing electromechanical work. If you guys have any technical questions feel free to shoot them to me.


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## artmart (Sep 21, 2010)

Thanks for the offer!!! We could tell you are no slouch from the many posts you've provided.

I could use some help with some electrical work at the stick house. I find the hardest part of household electrical work is getting wires to places they don't exist and keeping them hidden (mostly running new AC wires). On the other hand, I hate wireless since I am a security hound and wireless is NOT secure.

I'm sorta kidding about the help. I can do these things, I'm just lazy.


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## crawford (Nov 25, 2009)

*Shadow help needed PLEASE*

Shadow need help. I put on ball jacks added on power paks which is a motor gear drive battery driven. Just a red wire and black on each 4 total jacks. Problem they require large Gage wire to switches. I would like to put in relays close to house battery compartment.Run heavy Gage and then light wire to switches. The switches on reverses the motors to go up and down. Right now I have run heave Gage wire to switches but its a large rat nest and help we would be grateful. :10001::smack-head: Crawford:scratchhead:


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## Shadow (Oct 24, 2011)

crawford said:


> Shadow need help. I put on ball jacks added on power paks which is a motor gear drive battery driven. Just a red wire and black on each 4 total jacks. Problem they require large Gage wire to switches. I would like to put in relays close to house battery compartment.Run heavy Gage and then light wire to switches. The switches on reverses the motors to go up and down. Right now I have run heave Gage wire to switches but its a large rat nest and help we would be grateful. :10001::smack-head: Crawford:scratchhead:


Your description is a bit confusing, but I think you are saying you want to set up some relays to handle the load switching on the motor, and use a low voltage trigger from the switches to trip the relay. If you can get me a schematic of the circuit and some specs it shouldn't be too hard to figure out. As it stands now though I don't have enough information.


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## hideout (Feb 12, 2011)

most rv places will sell a fan kit,:thumbup1: so you can put a fan on your vent.


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## Shadow (Oct 24, 2011)

Found this one with a quick google search. 

Amazon.com: Heng's 90043-CR Vortex 12 V Exhaust Vent Kit: Automotive

A bit more expensive than a DIY but it looks good and seems like you just hook it up to the power and screw it on the vent.


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