Ant

Here's the summary:

- A push button is used to start a supply fan (controller 1).
- A return fan (controller 2) is interlocked to start automatically with the supply fan.
- In the event of a smoke condition the fans shutdown automatically.
- The supply and return fans cannot be restarted until the smoke detector system is reset (a latching relay is going to be used).
- In the case of excessive smoke, an exhaust fan (controller 3) can be started but only if the smoke detector system has not been reset.

A need to create a ladder and wire diagram.

I'm having problems from the third step down.

MDShunk

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

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

John Valdes

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?

mg42

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

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If the applicant is young, tell him he's too young. Old, too old. Fat, too fat. If the applicant then waits for three days without food, shelter, or encouragement he may then enter and begin his training

MDShunk

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

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

Ant

Yeah, separate from the supply and return air.

mg42

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"

__________________
If the applicant is young, tell him he's too young. Old, too old. Fat, too fat. If the applicant then waits for three days without food, shelter, or encouragement he may then enter and begin his training

mg42

So, how's that ladder diagram coming along?

__________________
If the applicant is young, tell him he's too young. Old, too old. Fat, too fat. If the applicant then waits for three days without food, shelter, or encouragement he may then enter and begin his training

Ant

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

leland

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

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.

John Valdes

I am now learning how to use Microsoft Paint. Thanks

cdnelectrician

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.