# I need help with a control wiring circuit (homework)



## MDShunk (Jan 7, 2007)

Common setup. Google "ANSUL fan" and "FA Shutdown" or search on this site for "ANSUL".

Show us what you have worked up so far. Nobody's going to do your homework for you, but we can help you with what you have worked up on your own.


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## Ant (May 17, 2009)

*This is what I have:*

http://img190.imageshack.us/img190/6550/66698843.png


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## John Valdes (May 17, 2007)

I would love to help you but I have no idea how to add, delete or change anything in your drawing. Whats the format the drawing is in?


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## mg42 (Jan 27, 2009)

Remove the two last lines you added.

In order to make your third Fan work:

-The smoke detector must be active

-The excessive smoke detector must also be active

Translate this into a simple ladder line:thumbup:


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## MDShunk (Jan 7, 2007)

Since I've never heard of an "excessive smoke detector", I suspect that you want to the extra extractor fan to come on with a manual pushbutton, or maybe a timer?


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## Ant (May 17, 2009)

I did the drawing in Windows Paint so I guess you can open it up with that.


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## Ant (May 17, 2009)

> Since I've never heard of an "excessive smoke detector", I suspect that you want to the extra extractor fan to come on with a manual pushbutton, or maybe a timer?


Yeah, separate from the supply and return air.


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## mg42 (Jan 27, 2009)

MDShunk said:


> Since I've never heard of an "excessive smoke detector", I suspect that you want to the extra extractor fan to come on with a manual pushbutton, or maybe a timer?


I don't know the name of the device that detects the excessive smoke from the regular smoke. So I called it the "excessive smoke detector":beta1:


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## mg42 (Jan 27, 2009)

So, how's that ladder diagram coming along?


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## Ant (May 17, 2009)

*This is what I came up with:*

http://img265.imageshack.us/img265/1642/project.jpg


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## leland (Dec 28, 2007)

I see alot of switches(contacts) but no control to coils.
Assuming there is some,when the supply turns on where is the proof switch to turn on the return?

You are getting there,keep at it.


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## JElectriCC (Apr 20, 2009)

Why is their a hand/off/auto in your diagram now? did you change the control specs? 

Anyways, a normally closed contact could be placed before your fan 1 coil. If smoke detector detects smoke and opens the contact, fan 1 will de-energize and and the interlock will open, causing fan 2 to stop.
To run the exhaust fan, just put controller three in series with a normally open contact that closes when the latch is tripped, then in series with the fan coil. 

Run the latch to a control relay to give you the contacts needed.


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## John Valdes (May 17, 2007)

I am now learning how to use Microsoft Paint. Thanks


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## cdnelectrician (Mar 14, 2008)

Why is there a H/O/A switch? is it required? I built a similar system for a refrigerant exhaust system in a mechanical room. Except I used a 4 pole double throw relay in place of a latching relay.


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