Trouble figuring out what goes where in wiring fan motor.
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Trouble figuring out what goes where in wiring fan motor.
Thanks in advance for any help you might be able to offer.
I'm trying to figure out what goes where, in wiring a bathroom fan motor. It is a reversomatic twospeed fan QCF125CO that looks like this:

It needs to go through a relay DPDT - http://data.datasheetlib.com/pdf1/11...90380a6fa5.pdf
Using my neighbour's fan wiring as a model, I set it up like his and was able to get the high speed position to work but not the low.

would really appreciate any help you could offer. i'm hoping that one of the wires is just in the wrong position, but know very little about wiring.
thanks!
I'm trying to figure out what goes where, in wiring a bathroom fan motor. It is a reversomatic twospeed fan QCF125CO that looks like this:

It needs to go through a relay DPDT - http://data.datasheetlib.com/pdf1/11...90380a6fa5.pdf
Using my neighbour's fan wiring as a model, I set it up like his and was able to get the high speed position to work but not the low.

would really appreciate any help you could offer. i'm hoping that one of the wires is just in the wrong position, but know very little about wiring.
thanks!
#2
Welcome to the forums.

You don't need a relay to select speeds..... you need a SPDT (single pole double throw) switch. Now that you have the fan wires on a relay.... how did you plan to control the relay ??
You now would need a power switch to turn the fan on and another switch to activate the relay to select hi and low speed.... a little redundant.
You really need a switch like in the link. You would connect the switch to the fan with a three wire cable. Switch up is high - center is off - down is low.
Leviton 1257-W Toggle AC Quiet Wall Switch; 1-Pole, SPDT, 120/277 Volt AC, White - Crescent Electric
OR for decora style ..........
Amazon/Leviton-5657-2W-Single-Pole-Commercial-Grounding-SWITCH

You don't need a relay to select speeds..... you need a SPDT (single pole double throw) switch. Now that you have the fan wires on a relay.... how did you plan to control the relay ??
You now would need a power switch to turn the fan on and another switch to activate the relay to select hi and low speed.... a little redundant.
You really need a switch like in the link. You would connect the switch to the fan with a three wire cable. Switch up is high - center is off - down is low.
Leviton 1257-W Toggle AC Quiet Wall Switch; 1-Pole, SPDT, 120/277 Volt AC, White - Crescent Electric
OR for decora style ..........
Amazon/Leviton-5657-2W-Single-Pole-Commercial-Grounding-SWITCH
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To expand on what PJ wrote the switch needs to have three positions, two "on" positions and an "off" position. The switches he linked to have these and that is why they are as expensive as they are.
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Thanks for the replies!
This fan is actually part of my air circulation, so it needs to be on low power when the switch is not in the ON position, and when the switch (a light switch in my bathroom) is thrown, it then goes to high power. The relay came supplied with the unit, so that's kind of what I have at my disposal.
I have all of these parts already - just figuring out how to get them working. The three speed thing is just part of the schematic - I really only need two speeds.
Thanks!
This fan is actually part of my air circulation, so it needs to be on low power when the switch is not in the ON position, and when the switch (a light switch in my bathroom) is thrown, it then goes to high power. The relay came supplied with the unit, so that's kind of what I have at my disposal.
I have all of these parts already - just figuring out how to get them working. The three speed thing is just part of the schematic - I really only need two speeds.
Thanks!
#5
That information should have been included with your first post.
The fan is only two speed. The switch we were referring to was three position.
There is still a lot of information that we don't know.
What actually activates the relay..... is there a connection to your air circulation system ?
You have a standard wall switch in the bathroom to control the fan ?
Is the relay coil voltage 120vac ?
The wiring should be easy once we know what needs to happen.

I'm not found of an exhaust fan running 24 hours a day. I'd want the air circulation system to activate the relay for low and the wall switch to bring the fan on high.
The fan is only two speed. The switch we were referring to was three position.
There is still a lot of information that we don't know.
What actually activates the relay..... is there a connection to your air circulation system ?
You have a standard wall switch in the bathroom to control the fan ?
Is the relay coil voltage 120vac ?
The wiring should be easy once we know what needs to happen.

I'm not found of an exhaust fan running 24 hours a day. I'd want the air circulation system to activate the relay for low and the wall switch to bring the fan on high.
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Apologies for the omissions.
The fan connects to a light switch on the bathroom wall. There is no connection to the air circulation system, if I'm understanding it correctly, and I'm not sure that I am.
The reason it is always on is because I live in a very poorly built condo that was all I could afford, and the fan running 24hrs is necessary for circulation to be up to code. Not a lot of windows that open in a cheap concrete box.
I'm not sure what the "relay coil voltage" is. Is there an easy way to check (as in, something a novice could figure out)?
I should add that this system was running fine previously - I needed to replace the burnt out motor and I stupidly neglected to record the wiring position. I wish I could say this was a first.
Thanks for your help!
The fan connects to a light switch on the bathroom wall. There is no connection to the air circulation system, if I'm understanding it correctly, and I'm not sure that I am.
The reason it is always on is because I live in a very poorly built condo that was all I could afford, and the fan running 24hrs is necessary for circulation to be up to code. Not a lot of windows that open in a cheap concrete box.
I'm not sure what the "relay coil voltage" is. Is there an easy way to check (as in, something a novice could figure out)?
I should add that this system was running fine previously - I needed to replace the burnt out motor and I stupidly neglected to record the wiring position. I wish I could say this was a first.
Thanks for your help!
#7
I closed your other thread.... two threads running on the same topic are are hard to follow and confusing.
No problem. We'll get it running.
If the system was already working then the coil is 120vac.
The problem with an exhaust fan running 24 hours a day is that it needs to bring in fresh air (take that as cold unheated air) and discharge heated air.
I see wiring in your picture. Can you tell us how many cables you have there and what colors are in them.
It looks like the relay may be at the fan and that you only have 2) two wire cables there. That should mean one cable for power and one for the switch.
No problem. We'll get it running.
If the system was already working then the coil is 120vac.
The problem with an exhaust fan running 24 hours a day is that it needs to bring in fresh air (take that as cold unheated air) and discharge heated air.
I see wiring in your picture. Can you tell us how many cables you have there and what colors are in them.
It looks like the relay may be at the fan and that you only have 2) two wire cables there. That should mean one cable for power and one for the switch.
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Coming out of the fan motor are a red, black and white cable. On the other end are a red, black and white cable that attach to a white plastic clip connector that plugs into the system/lightswitch.
I cut the cables to emulate the previous situation, and added contact end clip things to the new ends. So there's a red and black from the fan side and a red and black from the lightswitch side.
The white cables, to emulate the previous wiring, are twisted together, along with a short white cable that has an end clip on it to attach to the relay. So one white connector.
There's also a green ground wire that I attach to the metal housing. Really appreciate your help.
I cut the cables to emulate the previous situation, and added contact end clip things to the new ends. So there's a red and black from the fan side and a red and black from the lightswitch side.
The white cables, to emulate the previous wiring, are twisted together, along with a short white cable that has an end clip on it to attach to the relay. So one white connector.
There's also a green ground wire that I attach to the metal housing. Really appreciate your help.

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Update:
In the position shown in the last photo, when the switch was on, the high speed engaged, but when off, though there was a hum, the fan did not move.
As an experiment, i switched the position of the reds and blacks, and when I did this, in the switched off position the fan ran high, and when switched on, the fan ran low. There was a hum as well, though I honestly can't recall if that is normal, since it is not so loud over the sound of the fan.
Position:
B 0
R 0
R 0
W B
In the position shown in the last photo, when the switch was on, the high speed engaged, but when off, though there was a hum, the fan did not move.
As an experiment, i switched the position of the reds and blacks, and when I did this, in the switched off position the fan ran high, and when switched on, the fan ran low. There was a hum as well, though I honestly can't recall if that is normal, since it is not so loud over the sound of the fan.
Position:
B 0
R 0
R 0
W B
#10
The following diagram should be what you need. I don't know which wire is always hot and which is switched from the switch so you may have to reverse the switch red and black wires.
