Attic Exhaust Fan wiring

With the summer heat we have noticed our 2nd floor isn't cooling off. I took a look in our attic and noticed the exhaust fan isnt running. Opened the junction box and noticed one of its white wire was disconnected. The Black wire is connected. Testing the power the only live wire is red. I do see two sets of white wires.

 

Do you have a main floor switch and if you do can you fiure out which set of wires go to or come from the switch?

 

The fan will not operate w/o the white conductor connected.

However, you have the option of determining, if, there is a switch leg, or, install a temperature controlled switch, at the open "J" box, instead of a mechanical switch.

 

Have you ever had this fan running before.
If yes and nothing was changed you might look in the wire nuts on the white wires to see if a wire just broke leaving some evidence where it was.

There are just to many wires to say this is easy, this box could also be a junction box for another circuit or something.

 

Where is the neutral conductor, from the BX, which is sticking up in the air, connected?

 

Why is there an extra black wire.

 

I've identified where the white conductor, which is not connected is, so; "Where is the neutral conductor, from the BX, which is sticking up in the air, connected?"

 

Are you assuming the BX is going to the fan?

 

Only if that would be a clue why the fan isn't operating.

 

Just not enough info for me to make a suggestion.

We don't know if the OP knows the whole story. I will wait for him to come back with some answers.

 

In post #2 you asked about a switch.

A switched load requires a neutral connection to operate.

 

So far I agree with every thing you are seeing but I am thinking that someone else may have disconnected it for a reason.

 

It doesn't appear to have ever been connected.

 

I noticed that there are conductors coming out of the bottom conduit and going right back out the top one as in a "loop". Hard to make out what conductors are from what conduit etc.
Also I would not assume that any of the conductors going through the conduits are for specific functions such as white will be neutral, black hot etc (nothing is marked). as we don't know who ever put this together did not just use more red because they had more of that color than white etc.

We also don't know if this ever worked before or just stopped working suddenly. We also don't know if there is any type of thermostat connected somewhere else and there seems to be a lot of wires to just control one attic fan so that means something else is running off the circuit beside the attic fan. The OP has to trace where these wires are coming/going and let us know.

 

As far as I know, this fan never ran. This is my first time up there and when I opened the junction box feeding it I found that white wire disconnected. I am pretty sure the fan itself is dead or seized. Unfortunately, the motor doesn't have any markings. I may just replace it with a solar power fan.

 

If you have not, and do not connect the white conductor, how do you know the condition of the fan?

 

Promethus defied the gods and gave fire to the humans, you want to be care full you might be giving it back

 

But he's just bound, and not there yet, so he may be surprised to find the METHUSELAH, is my younger brother.